Nico di Angelo

"Just who I am... Easy for you to say. You're everybody's golden boy, the son of Jupiter. The only person who ever accepted me was Bianca, and she died! I didn't choose any of this. My father, my feelings..."

- Nico to Jason Grace

Nico di Angelo is a fourteen-year-old Italian born-Greek demigod, the son of Hades and Maria di Angelo. He is also the younger brother of the late Bianca di Angelo and the paternal half brother of Hazel Levesque. He is known in the Underworld as the "Ghost King" after taking the title from King Minos. He is currently in a relationship with Will Solace.

Early Life
Nico di Angelo was born sometime in the mid to late 1930's in Venice, Italy, before World War II (before Hades and his brothers took an oath to have no more demigod children). Since Nico was born in Italy and his mother was Italian (the daughter of a diplomat in Washington D.C.), he can speak fluent Italian. He had an older sister named Bianca di Angelo. Around the age of six, Nico visited Diocletian's Palace in Split, Croatia. One of his neighbors, Pietro, had been a veteran of Mussolini's African campaign. In The Blood of Olympus, Nico sees a brief flashback from this time - his mother smiling down at him while they both walked by the Venetian Grand Canal.

Relocation and Losing his Mother
At some point near the beginning of World War II, Nico and his family left Italy for the United States, where they stayed at a fancy hotel in Washington, D.C. Their mother, Maria, died when Zeus struck the hotel they were staying in with lightning in an attempt to kill the siblings, which he failed .However, they were protected by Hades as he erected an impenetrable wall of black energy to shield them from Zeus' bolts but Hades was not able to protect their mother in time. Afterwards, a devastated Hades ordered the Fury Alecto to take Nico and Bianca to the Underworld and bathe them in the River Lethe, in order to wipe away their memories.

Washington D.C. and the Lotus Hotel and Casino
In The Titan's Curse, Bianca recalls that shortly after she and Nico had their memories wiped, they were returned to Washington D.C. and told by a lawyer (Alecto in disguise) that their parents were dead, and had left a bank trust for them. This "lawyer" would come by once in a while to check on both of them. During this time, Nico and Bianca were enrolled in a boarding school. During this time, Bianca familiarised herself with the city's subway system. In The Blood of Olympus, Nico sees a brief flashback from this time - his sister Bianca, laughing as she pulled him across the National Mall. After some time had passed, Hades, hoping that one of his children might one day become the "child of the Eldest Gods" (referred to in the Great Prophecy), decided to place them in the Lotus Hotel and Casino, and tasked Alecto with the job. Once again disguised as a lawyer, Alecto had Nico and Bianca leave the boarding school, and took them all the way to the Lotus Hotel, in Las Vegas.

After what the siblings thought was a month in the Lotus Hotel (which was actually 70 years), they were taken out by Alecto, this time disguised as a different lawyer. Alecto drove Nico and Bianca back east, through D.C., and then up into Maine. They were brought to a military school called Westover Hall, paid for by Hades using what Nico and Bianca thought to be a trust fund left to them by their parents. It was later revealed that Nico had been obsessed with pirates even before he started collecting Mythomagic cards. Bianca mentioned that the summer before she left Westover Hall (during the events of The Sea of Monsters), she and Nico visited Washington D.C. once again, and were very surprised to see several subway stations that had not been there before. In The Titan's Curse, Bianca mentions that during their visit, several monsters (disguised as mortals) attempted to attack them in an alley. Nico also mentions seeing a bus driver (most likely a satyr in disguise) with ram's horns, though Bianca had not believed him at the time.

The Titan's Curse
Nico first appears with his sister, in a military school called Westover Hall in Bar Harbor, Maine. Bianca and Nico were almost kidnapped by a manticore named Dr. Thorn. Thalia Grace, Grover Underwood, Percy, and Annabeth Chase attempted to save them, but it is the Hunters of Artemis who come to the rescue. The siblings were sought out by Grover, who believed them to be two very powerful unknown half-bloods. Nico looks to be about ten and seems to be very interested in Mythomagic, a card game about Greek mythology. But when twelve year-old Bianca accepts Artemis' proposal to become a Hunter, Nico gets angry at her for abandoning him. Right before Bianca departs, Percy finds Nico eavesdropping on Bianca and Zoë Nightshade, and Nico successfully convinces Percy to promise to keep his sister safe on the quest. It is later revealed in The Last Olympian that at some point during his first stay at Camp Half-Blood, Nico stopped by and spoke to the goddess Hestia, becoming the first demigod to do so in many years.

He doesn't appear again until after Percy returns from the quest, where Percy explains to him that Bianca died to save the others on the quest, being killed by a smaller version of Talos when she grabbed a Hades Mythomagic figure for Nico to have. He immediately turns on Percy, telling him he hates him, and reminding him of the promise he made to keep Bianca safe. Percy tries to comfort him, and Nico claims he can sense her soul being judged. When the last four Skeleton Warriors appear in the camp, Nico, not wanting them to hurt Percy, tells them to "Go away!" and they are swallowed by a fissure in the ground that Nico creates by accident. Nico is last seen running into the woods at night. Percy then realises that Nico is a son of Hades after slipping over on and finding the god figurine that Bianca told Percy to give Nico if she died. It was the only one he didn't have (in his Mythomagic collection). The figurine was Hades, Lord of the Dead. He left the camp through Daedalus' Labyrinth, where he would meet Minos.

It is later revealed that another major reason he ran away that day was love - his romantic feelings for Percy that terrified Nico, who could not initially come to terms with them. Nico later claims in The House of Hades, that this revelation would plague him with self-hatred and resentment for Percy.

The Battle of the Labyrinth
The ghost of King Minos found Nico di Angelo in the Labyrinth, and intended to manipulate the son of Hades into killing Daedalus in revenge for his unjust, however much deserved, death. In order to gain Nico's trust, Minos leads him through the maze, saving him multiple times, and training him how to utilise his infernal demigod powers. Hence, it is most likely that Minos was also the one to teach Nico to shadow travel. Nico later mentions that while trying to master this ability, he initially kept running into walls, and made several accidental trips to China. Nico is first seen through the Iris message that Bianca sent to Percy. Nico tried to summon Bianca's ghost many times, but failed. Frustrated, he seeks to make a deal with his father by trading "a soul for a soul." Percy thinks that Nico is after him, but Nico is actually after somebody else.

Nico decides to find the soul of someone who cheated death and trade it for Bianca's, along the way, he summons the soul of Theseus for advice. Later, Nico unexpectedly meets Percy, Annabeth, Tyson, and Grover at the Triple G Ranch. He'd entered the ranch to discuss finding the soul he needed with Geryon. Angered, he threatens them, but is stopped by Geryon. Nico still blames Percy for Bianca's death, and tells him so. He is then tied up by Geryon to be sold to the Titan Army. When Percy offers a deal to Geryon to save him, Nico shouts that he does not want to be saved by Percy.

Nonetheless, Percy still saves Nico, killing Geryon with the help of Hera and convinces him to try and summon Bianca's spirit again. It works, however, Bianca tells Nico not to be angry at Percy or hold grudges, because that is the fatal flaw of the children of Hades. She says to stop blaming Percy because it is really she that Nico is angry at for abandoning him. She also gives a warning about Kronos sensing Nico, and then she disappears.

He stays at the Triple G Ranch while the others leave. Nico is tricked by Minos into going back into the maze to save Percy, but is captured by two dracanae in Kronos' army. In the battle at Daedalus' Workshop, Nico opens a fissure in the ground, sending Minos back to the underworld. He tells Percy that only the dead accept him, and they only do so out of fear.

He escapes with Percy, Annabeth, and Rachel Elizabeth Dare, who have to go back into the Labyrinth to find Grover and Tyson. Along the way, they see Kronos (in the form of Luke Castellan), and Nico, in a desperate attempt to save everyone, shows his true powers, by conjuring a wall of black stone that stops Kronos from following them back into the Labyrinth but also makes it known to Kronos that he is a son of Hades.

When they find Grover and Tyson, they also find the long-lost god Pan, and Nico notices that he is the only one that Pan doesn't talk to.

During the battle at Camp Half Blood, Nico summons many undead warriors to fight, and manages to stop some rogue dracanae from reaching the cabins of the gods. The effort nearly kills him and he collapses on the ground, his clothes smoking, at the end of the battle. Percy finds him and helps him by giving him nectar. He releases Daedalus' soul after that, who offers his soul for ransom, but Nico decides Bianca should stay where she is.

He feels out of place at Camp Half-Blood, and refuses to eat with the other demigods or join the singalong at the campfire. Nico summons Bianca's spirit one last time to say goodbye. He tells Percy that he will leave Camp Half-Blood because he feels that he doesn't belong there like his father doesn't belong on Olympus. Before he leaves, Percy gives him the small Hades statue that Bianca had given him before she died.

He appears again at the very end on Percy's birthday at his apartment, and offers a way to defeat Kronos, but is distracted by Percy's blue birthday cake. Percy offers him some, and they both go inside to talk about Nico's secret plan to beat Kronos.

The Sword of Hades
Nico is one of the three demigods along with Thalia and Percy who are summoned by his step-mother Persephone to find the Sword of Hades. Percy thinks it's a bad idea but Nico is hoping to achieve recognition from his father Hades. He tells Thalia and Percy why they need to go on the quest. To Percy's irritation, he comes up with logical reasons. His knowledge of the Underworld and its occupants helps them complete their quest. He remains in the Underworld afterwards to discuss the upcoming Titan War with his father. Before his friends leave, he reminds Percy of his idea to defeat the Titans.

The Last Olympian
Nico's theory to gain an edge over the Titans is finally revealed: it is to make Percy invincible by having him bathe in the River Styx, similar to the myth of Achilles. It is later revealed that Nico had hoped that this would also make Percy fall in love with him. It is shown that after Bianca died, Hades believes that he has no competent child, repeatedly mentioning that Bianca could do a better job at fulfilling their father's demands. At some point earlier, Nico began preparing for his plan, and did some research on Luke's past, and had found May Castellan, his mother.

Later on, Nico is once more searching for information about his mother and childhood, a quest which brought him to  Mount Othrys/ Olympus. Nico is first seen there in Percy's dream, using a chance to eavesdrop on the Titans Hyperion and Krios, as well as the imprisoned Atlas. It is later confirmed that this was true. Shortly after Beckendorf sacrifices his life to destroy Kronos's ship, Nico speaks to his ghost, and learns that Beckendorf will go to Elysium. Nico himself also heard the lines of the Great Prophecy, presumably from another ghost, or Hades himself.

Later on, Nico arrives at Camp Half-Blood by shadow-travel, which initially terrifies Juniper and Leneus, and he briefly discusses Grover's disappearance with them, after which he encounters Percy. Nico is finally able to persuade him to go through with their plan, and both of them and Mrs. O'Leary shadow-travel to Luke's old house to meet his mother, May Castellan. Afterwards, they briefly encounter the goddess Hestia, who greets them warmly and offers them food.

Soon after, the three enter the Underworld, where Nico, who was tricking Percy all along, had the Furies carry them to Hades' Palace. It is revealed, that in order to gain information about his past and his mother, Nico had to bring Percy to Hades in exchange, and though Nico had no ill intentions, and only did it after making Hades promise not to harm his friend. His father reveals that the lawyer who removed Nico and Bianca from the Lotus Hotel and Casino was the Fury, Alecto, in disguise, but refuses to give him details on his mother's death. After Hades still imprisons Percy in his dungeons, Nico helps him break out, apologises, and still follows through with his initial plan of having Percy bathe in the Styx and gain the Curse of Achilles. After Percy bathes in the Styx and got the Curse of Achilles, he was able to defeat Hades and his entire army of the dead.

Later, Nico attempts to summon the ghost of his mother, but Bianca's ghost appears and tells him not to. He sees the scene of their mother's death in which Zeus blasted the hotel she, Hades, and the children were into pieces. Hades, who realised what was happening too late, only managed to save Nico and Bianca. He then orders Alecto to wipe the memories of the children in the Lethe, including their mother's death.

By viewing this scene, Nico finds out who his mother is and, in the end, is able to convince his father Hades to help the campers in battle.

Nico is the first to join the Battle of Manhattan, and fearlessly yells out a challenge to Kronos himself. Nico is soon joined by Hades himself, and they both summon wave after wave of the undead soldiers, who confront, and eventually overwhelm Kronos' forces. After the Titan Lord is defeated, Nico accompanies his father to Olympus, and sits at his father's feet when Percy and his friends are receiving gifts from the Olympians. Apparently, Nico, through his unwavering loyalty and bravery in battle, has finally gained his father's pride, as Hades even pats Nico on the shoulder, and, according to Percy, this is "the happiest he's ever seen him." Since Hades is now accepted on Olympus, and Nico is accepted at Camp Half-Blood, Rachel is finally able to break Hades's curse on the Oracle, and become the next Oracle of Delphi herself. Apparently, almost all campers are in awe of Nico's fighting in Battle of Manhattan, as "even the Ares kids considered him cool." Nico is last seen when he orders undead workers to build the Hades cabin, made up of solid black obsidian walls with a skull over the door. There are torches inside that blaze with burning green fire that will never extinguish.

Sadly, Nico's popularity only lasted a few weeks. After that campers did whatever they could to avoid him and forgot he was at camp. (Though a year or so later Will tells him this never happened, he himself isolated himself). The fact that Percy had begun dating Annabeth did not make Nico feel any better. As a result, Nico takes to only showing up at Camp from time to time. Sometime after the Battle of Manhattan, Hades gave Nico a French zombie chauffeur, Jules-Albert, for his birthday.

Between the Series
As revealed in The Son of Neptune, in the September following the Battle of Manhattan, after Thanatos had been captured, and the dead were returning to the world anyway, Nico had gone to the Underworld in hopes of rescuing his sister Bianca, but was unable to do so, because she decided to be reborn and thus couldn't be brought back to life. Instead, Nico found his half sister Hazel Levesque in the Fields of Asphodel, and felt that she deserved another chance at being a hero (Gaea said that he had selfish reasons for doing this, but it is unknown if he had any or for what selfish reasons did he do it for). Hades gives Nico directions on how to find Camp Jupiter, explains why the Olympians have kept both camps separated for centuries, and forbids him from telling anybody about it, as the time isn't right. Hades also advises his son to introduce himself to the Romans as a son of Pluto, telling Nico that it is important for him to make this connection. As stated by Dakota, Nico took Hazel directly to Camp Jupiter and requested that Reyna Avila Ramírez-Arellano and Jason to take her in. Thus, Nico became the first Greek demigod since the First Demigod Civil War to learn about the existence of Roman demigods, and to visit Camp Jupiter. He accepts a role as the Ambassador of Pluto to the Romans, and becomes involved in the camp's political life as a Senator.

The Lost Hero
Annabeth mentions that Nico is searching for Percy along with Tyson, Grover, and the Hunters of Artemis, but otherwise he doesn't appear. It's to be assumed that he doesn't stay at Camp Half-Blood much, as Annabeth said he "sometimes" shows up, which could be due to his double duty at Camp Jupiter as Ambassador of Pluto. She mentions him as one of the only children of the big three along with Percy Jackson and Thalia Grace. Unknowingly to her, Jason Grace is also a child of the big three, of Jupiter.

The Son of Neptune
Nico meets Percy at Camp Jupiter, where he is visiting his half-sister, Hazel Levesque. When they meet, Nico is shocked but easily regains control. He poses as a son and ambassador of Pluto, and even though most of the campers see him as harmless, Hazel knows that Nico is more dangerous than Reyna, Octavian, and maybe even Jason Grace. Nico tells Percy about the return and defeat of Kronos (referring to him as Saturn), and about Gaea. Nico later tells Hazel, after Percy leaves with Frank Zhang, that he knows Percy, but Percy must regain his memories by himself, since he needs to find his own way at the camp and Nico can't interfere. It is later revealed that Nico was forbidden to do so by Hades himself, since the time wasn't right yet. Hazel and Nico had time to talk when he mentioned Bianca, his late sister, saying that he missed his sister and he wanted to see her again.

Later, Nico is shown to be observing the War Games from afar using a pair of binoculars. When Mars appears, Mars glares at Nico while mentioning that people will no longer be held to death, implying that he knows about him saving Hazel's spirit. Nico is later shown in the meeting, where he is present as a Senator in a black toga, and the Ambassador of Pluto. Nico supports Frank, Percy, and Hazel by telling them about the first Gigantomachy, Alcyoneus, and Thanatos, all of which makes Reyna suspicious. However, Nico doesn't say anything when Octavian protests and wins the argument. Nico leaves Camp Jupiter before Hazel to see if he can locate the Doors of Death from inside the Underworld.

During his search, Nico (believing he could go anywhere in the Underworld) comes too close to Tartarus and gets pulled in by the dark gravity the pit generates (similar to a black hole). He was presumably forced to drink liquid fire from the Phlegethon in order to survive. At some point during his horrifying journey through Tartatus, Nico encounters the goddess of misery Akhlys, who was impressed at how much sorrow and pain the son of Hades carried, claiming that there was little more that she could do to him. Though he fought back, Nico was eventually overwhelmed and defeated by the sheer number of Gaea's forces down in Tartarus.

Nico is later shown in one of Hazel's flashback blackouts. He finds Hazel in the Fields of Asphodel and brings her back to the mortal world to give her another chance at life.

During the quest for the god Thanatos, Gaea mentions that when she used Hazel, she was at least honest about it, unlike Nico who she claims was lying to Hazel. Gaea also says that Hazel should be happy that she captured him, and that he is now somewhere in Rome. Gaea later tells this to Percy and he promises that they will find out what happened to him.

When they free Thanatos, Hazel asks if Nico is alive. While Thanatos doesn't say if he is alive or dead, he does say they will find the answers in Rome. Later after Percy regains his memory, he calls Mrs. O'Leary, much to Hazel's surprise. He tells her that Nico could tell her the story before realising what he had said. On the way back to Camp Jupiter, Percy fully regains his memory, and is quite angry at Nico for not telling him about his past. After Polybotes is defeated, Hazel mentions that Pluto is turning a blind eye to her to let her live and she feels that he wants her to find Nico.

The Mark of Athena
Even though Nico is a son of Hades, he barely survived the trip into Tartarus, and almost went insane much because of the number of Gaea's forces and how powerful they were down in Tartarus. Gaea's forces went down there and overwhelmed him almost instantly, since they are extremely powerful in Tartarus. Afterwards, in order to lure the seven heroes into a trap, Gaea had Nico transported out of Tartarus through the House of Hades (an underground temple in Greece), and taken to Rome, where her twin giant sons Otis and Ephialtes sealed him in a bronze jar, similar to how Ares was also once held captive by the two giants.

Percy sees him in his dream, imprisoned in the jar in a coma-like state. He had marked three scratches on the wall of the jar, one for each pomegranate seed he had eaten. The seeds are a last resort food, which only children of Hades/Pluto can eat. Hazel explains that the seeds last for up to one day and put him in a death like state so that he doesn't use up all his air, something Hazel calls a death trance.

Despite knowing that it's a trap, the Seven head to Rome to rescue Nico. After getting there, Hazel, Frank, and Leo try to find Nico, which leads them to the Pantheon, but they are lead into a trap, and are almost killed by eidolons. After defeating them, Leo realises that Hazel was trying to track Nico by using his sword as a beacon, which they find lying in the workshop.

Instead, Percy, Jason, and Piper come to Nico's rescue underneath the Colosseum. During Percy and Jason's battle against Otis and Ephialtes, the jar Nico was held in breaks open and Piper McLean manages to pull the incredibly weakened Nico to safety. Later back on the ship, Nico tells them how he was captured and what he now knows about the Doors of Death. Nico had found out that the Doors of Death have two sides: one in the mortal world and one in Tartarus. The mortal side of the portal is in Greece, at a temple called House of Hades and it is guarded heavily by Gaea's forces. Nico then says that the other side of the doors are in Tartarus, a place not even the gods go and that is why Hades has not been able to close the doors. Not even the god of death, Thanatos, would go near Tartarus.

Leo guesses that the seven heroes will have to go to Tartarus and close that side of the portal, but Nico says that it would be impossible, not even they would stand a chance down there. Percy then says that they can set sail for the House of Hades, defeat Gaea's forces, and close the doors on the mortal side. Nico however says that it is not that easy and that the Doors of Death have to be controlled on both sides to be closed, as they are like a double seal. He says that maybe all eight of them working together could defeat Gaea's forces on the mortal side, but that they would need a team fighting simultaneously on the Tartarus side; a team powerful enough to defeat a legion of monsters in their home territory.

In Arachne's lair, when Percy tries to save Annabeth from falling into Tartarus, Percy catches hold of a ledge just in time. Nico tries to help, but he is out of reach. Annabeth tells Percy to let go, but Percy says that he will not lose her again. Percy tells Nico that they will see the rest of the seven and Nico on the other side, and makes him promise to lead the others there. Nico promises and Percy lets go, allowing the dark gravity of Tartarus to pull him and Annabeth in. During a meeting on the Argo II, Nico admits that Percy is the most powerful demigod he has ever met and with Annabeth there with him, he is sure they will be safe. He assures Leo that both Percy and Annabeth are still alive.

The House of Hades
The Argo II is being attacked by numina montanums, or mountain gods, who are attacking with boulders. As they attack, a boulder hits the mast, causing it to collapse, and Nico, who was in the rigging, falls with it. Hazel Levesque runs to help Nico up from the debris, but he tells her he is fine. When Leo complains that masts don't grow on trees, Nico corrects him by saying that masts are made from trees, which only serves to annoy Leo further. Leo is forced to retreat again and the three try to think of an alternate way past the Earth gods.

Nico explains that they don't like them because children of Hades/Pluto get under their skin but adds that the Athena Parthenos was most likely attracting more attention. When it is suggested that they take the Argo II around the mountains over the water, Nico explains that going that way is longer and without their sea expert, Percy, it might be too dangerous. Nico also complains that he is too weak to simply Shadow Travel the ship across the mountains. While coming up with ideas, Hazel tries to think of a way to help, not wanting her only contribution to be removing a dangerous obstacle Nico had told her was in the House of Hades. When Hazel prays to her father for help, Arion appears, running towards them. Nico asks who Arion is and is told by Leo that he is Hazel's horse.

When Jason and Nico go to retrieve Diocletian's scepter in Split, Croatia, they meet the god Favonius has been watching Nico and hints at Nico's secret crush, commenting, "The one you care for most... plunged into Tartarus, and still you will not allow the truth?" He then leads the two boys to Cupid. Cupid forces Nico to admit that he had feelings for Percy, in front of Jason Grace, in order to get Diocletian's scepter. Jason attempts to comfort Nico and promises to keep it a secret, but Nico brushes Jason away.

Later Nico confronts Jason about leaving the palace of the Lord of the South Wind. Jason attempts to talk to Nico about what happened previously, saying that the others won't judge him. Nico becomes angry and claims that as a son of Hades he would never be accepted anywhere and always judged. In his anger, the ground opens up and Nico seems to shimmer with ghostly light. Jason then challenges him by saying that he should take a risk and believe that Jason really is his friend. As the scene reaches a climax, Nico tells Jason, "I'm going to honor my promise. I'll take you to Epirus. I'll help you close the Doors of Death. Then that's it. I'm leaving- forever." The son of Hades then disappears back into the shadows. Jason has stated multiple times that Nico di Angelo scares him when he gets angry.

At Epirus, Nico leads the group into the underground temple. He works with Frank Zhang to summon and control the dead legion against the group of monsters after the temple collapses and separates the group. The group reunites, and finds Percy and Annabeth Chase purged from the Doors of Death. They work together to fight the giant Clytius and when he is defeated, Nico and Hazel shadow-travel the group to safety as the temple caves in. Upon arriving at the surface, Nico and the group meet with and share a meal with Reyna Avila Ramírez-Arellano before Nico leaves to rest due to his future plans to Shadow Travel with the Athena Parthenos, Reyna, and Coach Hedge to Camp Half-Blood to help Reyna stop the impending civil war between the Greek and Roman camps.

At the end of the book, Nico ties the statue up with rope to be able to it and Percy comes to thank him for keeping his promise. Nico cuts him off and tells him to give him space. He then shadow travels away with Reyna and Coach Hedge.

Between the Series
Several days after the deaths of Gaea and Leo, a parchment scroll with a holographic message, sent from the resurrected Leo, came fluttering into Camp Half-Blood on the wind, with Nico being the one to keep it (in his jacket's pocket) after the other campers had finished re-listening to it. While extremely relieved after learning of Leo's survival (due to him having blamed himself for Leo's death and unable to forgive himself), Nico is also enraged at hearing the news so late, so he resorts to keeping the scroll after everyone else has finished re-listening to it, with Nico looking at the scroll whenever he wants to get angry at Leo.

At some point during the ensuing months, Nico finally comes out and confesses to Will Solace about having a strong crush on the latter, and the two begin dating. In order to sit together with his new boyfriend during meals, Nico claims to Chiron that he somewhat loses control of his infernal powers while sitting alone at the Hades' Cabin table, and so he is therefore given permission to sit at the Apollo's Cabin's table instead, as Will produced a handy fake doctor's note, and Chiron decided it wasn't worth arguing about.

By September, however, most of Nico's friends temporarily leave camp, with Percy and Annabeth returning to New York to spend their senior school year together, while Jason and Piper depart a month later (spending most of September searching for Leo), to spend their school year in Los Angeles (with Tristan McLean), also taking Gleeson Hedge, Mellie, and Chuck along with them. It can also be assumed that Nico is rarely visited by Hazel and Frank, as he describes them being busy "doing the Twelfth Legion thing” at Camp Jupiter.

The Hidden Oracle
Six months after Gaea's defeat, the banished and powerless Apollo and the demigod Meg McCaffrey arrive at camp, and Nico, as his son's boyfriend, greets the former god and his master by the Big House, able to see "an aura of death" around Apollo, a "thick possibility of death." During that evening's meal, Apollo sits next to the couple, which he claims is so cute together, that it made him feel desolate. During this time, Nico also tells Apollo about the current whereabouts of the Seven Heroes of Olympus. That evening, a shocked Nico witnesses the Karpoi Peaches save Meg from Sherman Yang and Connor Stoll, but he then tells the demigod to move out of the way (as Karpoi are dangerous). Meg, however, fiercely defends her Karpoi friend with her swords. Seconds later, when Meg is claimed by her mother Demeter, Nico and the other demigods present respectfully kneel.

Several days later, Nico and Will participate in Harley's three-legged death race through the Labyrinth, being bound together. After the race, Nico is seen helping his boyfriend in an impromptu hospital, holding down the screaming Paolo Montes while Will frantically tended to his wounds, and later assisting him in setting Valentina Diaz's broken arm.

Nico and Will also participate in a supportive going-away party for Apollo and Meg McCaffrey, during which Nico gives Meg some crucial ambrosia. When Apollo returned to camp, he was in Cabin seven with Will when Apollo awoke and told him to rest and that they were worried about him.

When the Colossus Neronis automaton attacked the camp, Nico and Will were in the canoe lake, so they promptly rushed over to the beach to help defend the camp. Nico shadow traveled with Will to a chariot flown by Sherman, Alice and Julia. Nico passed out from the effort, Will then takes the son of Hades to the infirmary. After the battle, he tends to the worst cases of hay fever.

When learning of Meg McCaffrey's true loyalty to Nero, a saddened Percy recalls how the camp had once lost Luke, and had almost lost Nico.

When Leo, Calypso, and Festus finally returned to camp (right after the defeat of the Colossus Neronis), Nico (having recovered fully) handed out numbers to all campers, so that they could get in line to greet and punch the returning son of Hephaestus, with Nico being the last to do so. When it is time for the sing-a-long, Nico is seen roasting marshmallows on some femur bones.

The Dark Prophecy
Apollo mentioned Nico when seeing Alaric the new second in command of Commodus.

Personality
In The Titan's Curse, Nico is ten years old and enjoys playing with his Mythomagic cards that none of the others truly seem to understand, and, as revealed in The Blood of Olympus he was obsessed with pirates even before that. He is clueless and very inquisitive: he is curious and questioning and likes Percy a lot like a big brother (though it is later revealed in The House of Hades that he has secret romantic feelings for him), and begins annoying Percy with his ceaseless questions, especially when he asks if Annabeth Chase was his girlfriend, which makes Percy consider "stuffing him in a meat flavoured sack and throwing him to the wolves." He is excited about finding out that he is a demigod (immediate response: "Cool!"), and starts to compare monsters to Mythomagic creatures. He feels abandoned when his sister Bianca, who practically acts as his parent, becomes a Hunter of Artemis. When she goes on a quest, Nico makes Percy promise to protect her. After her death, he develops a long-lasting grudge toward Percy for letting her die. Once he realizes that he is a son of Hades, he casts away his childhood interests and runs off on his own.

In The Battle of the Labyrinth, Nico becomes grim and solitary, and definitely a considerably more powerful character, saying that "only the dead respect me... and only out of fear." His attitude change may have happened partially because of Bianca's death and partially because of Minos' manipulations. He believes that he will never be accepted by the living, and does not belong at Camp Half-Blood, much like how his father Hades feels out of place on Olympus. Nico is also shown to be somewhat vengeful, as he wanted revenge for Bianca's death, something he blamed Percy for. However, Nico forgives Percy after Bianca's ghost tells him that it wasn't his fault that she died. He also accepts the small figurine of Hades that Bianca wanted him to have.

In the same book, he is shown to be very naive and gullible, being able to believe that Minos was actually helping him bring Bianca back from the dead. Nico cares much about his sister and the constant attempts to bring her back show that he would not give up without trying. Nico is shown to be very loyal to the Olympians, as he could have easily joined Kronos and the Titans, but chose to fight on the Olympians' side.

In The Last Olympian, he is quite sincere in wanting to help Percy with the prophecy and the war. However, Nico can be somewhat untrustworthy at times. This is shown when he tricked Percy into coming to the Underworld so he could gain answers about his mother, but Nico wasn't planning on Percy becoming imprisoned. By standing up to both Kronos and Hades, he is shown to be that he is very brave and bold. In fact, the only time Nico himself is ever shown to be terrified, is in The House of Hades, when he was forced to face Cupid, implying that Nico's greatest fear is exposing his homosexuality. He likes being on his own, not really wanting help from anyone. He keeps to himself a lot and is pretty secretive, which causes plenty of problems throughout the series. Nico wants to help Percy, and was very miserable at the thought that Percy did not trust him after his dad tricked him as well, by the end they were back to a brotherly relationship.

While he tries hard not to show it, Nico is plagued by incredible internal pain, mainly due to him being unable to come to terms with not "belonging" in the twenty-first century (due to the time he spent in the Lotus Casino), not being accepted by other demigods as a son of Hades, and, worst of all, his homosexuality (which he is desperate to keep secret). Some of his fears about not being accepted due to being gay, most likely come from growing up in the 1940s, where homosexuality was not accepted. At some point during his horrifying journey through Tartarus, Nico encounters the goddess of misery Akhlys, who was impressed at how much sorrow and pain the son of Hades carried, claiming that there was little more that she could do to him. When Reyna shares her strength with Nico in The Blood of Olympus, she is horrified at how much pain and raw anguish she felt inside the son of Hades, even a portion of it being greater than what she had felt from even her entire legion during the battle against the giant Polybotes. When Reyna accidentally learns about Nico's homosexuality, she, much to Nico's surprise and relief, doesn't judge him, and still accepts him as a friend just as he is, without hesitation. Reyna's acceptance was what most likely gave Nico the courage to finally come out to a very surprised Percy and Annabeth, but he admits to being over his formerly strong crush on Percy, and is now genuinely happy for Percy and Annabeth. Hence, Nico is finally willing to become more sociable and more open about himself and his feelings to others, no longer nearly so insecure about his homosexuality, to the point that he is completely open about it six months later in The Hidden Oracle. Nico, apparently, also has tremendous, virtually indomitable willpower, since he was able to survive in Tartarus on his own, while seeing the place in all of its ineffable horror for the entire time that he spent there. Percy, who found even a few moments of seeing it maddening, marveled how Nico had managed to survive with his sanity.

Nico is later proven wrong in the belief he will not be accepted by the living. After the war with Kronos is over, all the demigods of Camp Half-Blood welcome Nico cheerfully: as Percy puts it, "Hey, show up with an army of undead warriors to save the day, and suddenly you're everyone's best friend." This helps lift Hades's curse from the Oracle. Sadly, however, Nico's popularity only lasted a few weeks, after which most campers did whatever they could to avoid the son of Hades and forgot he was at camp. However, when Nico mentions his plans to leave for good, due to his lack of acceptance, Will Solace gets upset and tells him that there are actually many people at camp who are his friends or would like to be, but it is Nico who pushes himself away. Will also states that the camp did not reject him as he had thought. This indicates that Nico may have misinterpreted the campers' reactions to him, or exaggerated it in his own mind, due to his fears of non-acceptance. After Gaea is defeated, when Reyna tells the two camps about Nico's part in saving both of them, and gives him a big hug, the crowd of demigods roared with approval, indicating that thanks to Reyna, both Camp Half-Blood and Camp Jupiter have finally come to truly accept the son of Hades. As a result, Nico decides to give Camp Half-Blood another try, finally seeing that he is accepted.

In spite of Nico pretending not to know Percy in The Son of Neptune, he spoke very highly of him to Hazel, telling her that he is dangerous to his enemies and a valuable ally to his friends. Nico's relationship with Percy also shows how much he's grown and matured throughout the series. Nico is very caring to Hazel Levesque, his half sister, and tries to help her as much as he can. His helping her sort of parallels with how Percy helped him in several cases. This shows that he loves his family, even his half-siblings. Unfortunately, after returning from Tartarus in The Mark of Athena, Nico is very different. He turns more inward and withdrawn, with his eyes becoming somewhat glassy like something in him broke permanently. Percy compares him to pictures of prisoners of war, which he notes Nico kind of was. Hazels states in The House of Hades that Nico has become more reclusive and morose, preferring to stay on top of the ship's mast, in solitude. Nico becomes much more easily angered, defensive and takes to making creepy and humorless smiles. Nico, however, has happily smiled on two occasions: in The Last Olympian, right after he helps Hades defeat Kronos' army and gains his father's respect, and in The House of Hades, after he and Frank defeat Gaea's monsters at the Necromanteion. In The Blood of Olympus, Nico notes that his facial muscles hurt when he smiles, since he isn't used to making that expression often. Even though Nico seems to dislike being touched, he is shown to be very affectionate towards Hazel, having kissed her on the cheek several times. However, by the end of The Blood of Olympus, Nico begins to change, and doesn't seem to mind when Jason and Reyna embrace him.

Nico can be extremely dangerous as he is a son of the Big Three. He is very unpredictable, and due to his sister's death can be somewhat mentally unstable as demonstrated in The Battle of the Labyrinth, and Octavian even claims to see a decent amount of ruthlessness in Nico. He has a short temper, just like Percy and Thalia. When Jason causes him to lose his temper in The House of Hades, Nico's fury was so intense, that it even scared Jason, who felt that a furious Nico was "more than he could handle." However, the greatest and most volcanic demonstration of Nico's fury happened in The Blood of Olympus, when he faced the psychopathic Bryce Lawrence. A furious Nico, in one horrible cry, unleashes a "flood of pain and anger" on Bryce, Reyna, and Coach Hedge, with the temperature around Nico dropping to freezing (turning the ground around him white with frost), Bryce's zombies instantly disintegrating, and a terrified Bryce himself turned into a mindless ghost.

This otherworldly demonstration of Nico's sheer rage when unleashed upon those cruel enough to invoke it was one of the most frightening events in the series. Suffice it to say that no one and nothing would be wise to provoke the son of Hades.

By The Hidden Oracle, Nico is much happier and more involved in camp. He spends most of his time with his boyfriend Will, and is no longer insecure about being gay (although he still slightly uncomfortable with being called Will's "boyfriend"), and is considerably more relaxed around people, even roasting marshmallows on a campfire, joining in with the campers' sing-a-long, and helping Will tend to wounded demigods in the infirmary. Overall, Nico is very supportive of his boyfriend, even impressing Will's father Apollo.

Fatal Flaw
"Holding grudges has always been the fatal flaw of children of Hades."

- Bianca to Nico Nico di Angelo's fatal flaw is holding grudges, as Bianca's ghost tells him. In his case, it can lead to not wanting help or not asking to be saved in deadly situations because he simply doesn't like someone. Examples are his not wanting to be helped by Percy, even when Geryon was going to sell him to the Titans and not wanting to go back in the Labyrinth with them. Bianca shares this with him, as she also had the same fatal flaw in life, although this didn't lead to her death. Bianca also says that holding grudges is the fatal flaw of Hades' demigod children. In the fifth book, Nico tells his father, Hades, that he is holding a grudge that could end up killing the Olympians and the campers. Ever since The Last Olympian, Nico hasn't demonstrated this flaw any more, implying that he has learned from his previous experiences, and tends to avoid holding grudges. However, this flaw resurfaces slightly in The House of Hades, when Nico coerced by Cupid, admits to Jason that he had feelings for Percy, and yet still clearly bears some resentment toward Annabeth, and an unwillingness to accept that he will most likely not end up with Percy, despite the fact that he claims to Jason that he has, "…moved on." However, by the end of The Blood of Olympus, Nico is truly ready to move on, since he finally comes out to Percy and Annabeth about the strong crush that he used to have on the son of Poseidon, but admits that he has come to realize that Percy is not his type, and that he is truly happy for Percy and Annabeth. Nico now has a crush on Will Solace instead, who, as it turned out, reciprocated his feelings, which lead to them starting a romantic relationship at some point during the six months between The Blood of Olympus and The Hidden Oracle.

Irrational Fears
As finally revealed in The House of Hades, Nico's greatest fear is of someone finding out about his homosexuality. Therefore, he never stayed at either camp for long and did not make connections of friendship with most people, so as to keep them from finding out, becoming more isolated than any other demigod. This fear about not being accepted due to being gay, most likely comes from Nico growing up in the 1940s, where non-traditional sexual orientations were not accepted. Hence, in The House of Hades, when Cupid forcibly makes Nico reveal his secret in front of Jason, the usually intrepid Nico is nearly reduced to tears. When Reyna accidentally learns about his secret in The Blood of Olympus, she, much to Nico's surprise and relief, doesn't judge him, and still accepts him as a friend just as he is (though she is still very surprised at this revelation), supporting him without hesitation. Reyna's unconditional acceptance and support was what most likely gave Nico the courage to finally come out to a very surprised Percy and Annabeth at the end of The Blood of Olympus, indicating that Nico has finally begun to overcome this immense fear and insecurity of his. And by The Hidden Oracle, it is indicated that Nico has finally fully overcome it at some point during the six months after Gaea's defeat, finally coming out and confessing his crush on Will Solace, with whom he begins an official romantic relationship.

Appearance
Nico is said to have black hair that always looks like he just got out of bed (messy and shaggy) and olive skin. By The Battle of the Labyrinth, his skin has paled to white, and he takes to wearing black clothing with skeletal designs, a Stygian Iron sword and a silver skull ring (by the end of the book). By the time he meets Hazel Levesque, she describes his fingers as ghostly white, like their father's. It was stated by Percy that Nico has his mother's eyes, but it has also been said that he has the wild glint of a madman too, just like his father. According to Percy, Nico's hands are "as cold as ice."

By the end of The Battle of the Labyrinth, he has a silver skull ring which is said to belong to his father (as stated by Hazel), and he has a Stygian Iron sword always by his side in his chain belt. He is also mentioned on several occasions wearing an aviator's jacket, most likely because he was originally from WWII. Nico wears a black trench coat when he attempts to bring back Bianca, as shown in one of Hazel's blackouts. In The Last Olympian, Nico wears black battle armor with a skull-shaped helmet. In The Son of Neptune, Nico is seen wearing a black toga when Percy goes to talk to the senators (the reason being that togas are only worn on special occasions, like meetings). In The Mark of Athena, Nico appears weaker, thinner and even paler than usual, while his eyes are described as "looking like shattered glass," due to his ineffable experience in Tartarus.

Days later, in The House of Hades, Nico has begun to recover and regain his strength, but is still described as "painfully thin," with his black shirt and jeans hanging loosely from his "skeletal frame." His dark hair is longer and frames his face. However, the area around his sunken eyes is very dark, while his complexion is even more pale than before," a sickly greenish-white, like the color of tree sap." Being a demigod from another era, Nico radiates "a kind of old energy - a melancholy that came from knowing he didn't belong in the modern world." Nico is also the only one whose skin doesn't get tanned in the hot northern African sun, and if anything, looked even paler than before, according to Jason.

Jason comments that since getting out of Tartarus, Nico "had slept little and eaten even less." Seeing Nico casually eat a grape, he thinks that that will be his food for the day. Later, Jason is surprised then Nico actually has visible muscles when he takes off his jacket. According to Hazel, when upset, Nico's face would become "as dark as Tartarus." When Jason infuriates him, the ground opens up and Nico "glows with ghostly light." When Bryce infuriates him, the temperature around Nico drops to freezing, turning the ground around him white with frost. Several demigods, including Leo, Frank, and even Jason all admit to being afraid of the son of Hades.

In The Blood of Olympus, due to the stress of having to shadow-travel vast distances every day, Nico's skin gains a bluish tint, and his cheeks are sunken. After his aviator's jacket and black skull-pattern shirt are both torn to shreds, Nico begins wearing a tropical Puerto Rican shirt, decorated with parrots and palm trees, and with Isla del Encantorico written on it. His biceps are swollen and severely scarred from his fight with Lycaon, and after Reyna stitches them up for him, it gives Nico "a slightly creepy Frankenstein look," to the point that mortals on the street are scared off at the sight of him.

In The Hidden Oracle, Nico wears black trousers, a Ramones T-shirt, and a black leather bomber jacket, with his Stygian iron sword at his side.

Abilities and Tools
General Abilities=
 * ADHD: Like most demigods, Nico possesses inborn supernatural battle reflexes and senses that he uses to analyze the fighting style of his opponent.
 * Dyslexia: Nico's brain is "hard-wired" for divine Ancient Greek instead of modern languages.
 * Fighting skills: Initially, Nico shows more skill with his powers than his fighting skills. However, this might have been due to his lack of formal combat training at camp. In The Demigod Files, he did show decent combat skills when he was able to keep up with Percy and Thalia when they fought a group of Keres. Not only did Nico emerge unscathed from the battle, but he easily defeated the Keres he fought. Later, he even fought the Titan Iapetus alongside Percy and Thalia (but he was quickly incapacitated). In The Last Olympian, Nico fights in the Battle of Manhattan, and emerges unscathed, implying excellent fighting skills, which impress even the Ares demigods. In The Son of Neptune, Hazel mentions being impressed the first time she saw him fight, suggesting that he honed his skills between the two series, possibly during his stays at either Camp Half-Blood or Camp Jupiter. Nico was even able to fight Gaea's army in Tartarus itself, though he was eventually overwhelmed by their sheer numbers. In the House of Hades, Nico fights the enormous monster army of Gaea, while holding the Scepter of Diocletian high, and emerges unscathed after the battle is won, implying excellent swordsmanship. During that battle, Nico single-handedly overwhelmed an entire group of mighty Earthborn, slashing them into mounds of wet clay with his sword. In The Blood of Olympus, though somewhat weakened from shadow-travelling, Nico is still able to single-handedly quickly overcome 6 Roman legionnaires (while protecting Will Solace), and it should be noted that Nico was not even fighting to kill, only to knock them out. He later makes short work of Octavian's elite guard (6 huge dog-headed cynocephali). In the final battle with Gaea's troops at Camp Half-Blood, Nico fights at the front lines, managing to defeat numerous other monsters before being forced to leave (in order to confront Octavian at one of the onagers).
 * Mythomagic: Nico's knowledge of the game is superb, as he had the rare Africanus Extreme expansion deck, and remembers each figure, as well as the number of attack and defense moves of each. Thus, he was able to identify Dionysus, a Manticore and even a Katoblepone.
 * Ancient Greek: In The Battle of the Labyrinth, Nico demonstrates his ability to summon the dead by chanting in Ancient Greek.
 * Italian: In The House of Hades, Nico shows that he can speak fluent Italian, as he is Italian by birth. In addition, as shown in The Blood of Olympus, Nico's knowledge of Italian helps him somewhat understand some other Romance languages, such as Spanish and Portuguese (therefore notably being one of the few to understand Paolo Montes).
 * Will Power: Nico, apparently, has tremendous, seemingly indomitable willpower, since he was able to survive in Tartarus on his own, while seeing the place in all of its ineffable horror for the entire time he spent there. Percy, who found even a few moments of seeing it maddening, wondered how Nico had managed to survive with his sanity.
 * Pain Resilience: Nico was able to endure immense amounts of both physical and mental pain (notably even scars inflicted by Lycaon which "burned like acid"), much to Reyna's amazement and respect.

As a son of Hades, Nico is an extremely powerful demigod. He is considerably more trained in using his powers than most children of the Big Three, such as Thalia and Percy, due to his time spent in the Underworld and he states that he trains with the dead. In The Son of Neptune, Hazel stated Nico was the most powerful demigod she'd ever seen (to the point that she compared his power to that of a nuclear bomb), an impressive admiration given that she knew Jason Grace and dozens of other demigods (though meeting Percy caused her to question this judgment). In The Blood of Olympus, Reyna mentions that after being healed from his injuries by Hedge and resting for several days, Nico becomes significantly more powerful than ever before. Hazel once stated that she and Nico each control an aspect of Hades/Pluto's powers: death (for Nico) and riches (for Hazel).
 * -|Demigod Abilities=
 * Geokinesis: Nico can control the earth - levitating rocks and making them deadly, black, and extremely sharp. Nico can open fissures in the earth that can swallow up creatures and trap them in the Underworld. He can cause earth tremors so powerful, they can shatter the pillars of a mountain fortress. He can also control the black walls of the Underworld. His geokinetic abilities are only surpassed by his half-sister, Hazel Levesque and his father, Hades.
 * Necromancy: As a son of Hades, Nico has control over the dead, as well as many monsters native to Hades' realm, such as the Furies.
 * Power Over the Undead: Nico can reanimate skeletons, summon Skeleton Warriors, put them to sleep, and destroy them. In The Battle of the Labyrinth, Nico was able to permanently banish Minos to the Underworld. In The Last Olympian, he was able to summon a large army of undead soldiers all by himself. It is unknown how much he has increased in power since then. This is an extremely powerful ability as it literately allows him to have an army anytime he wants. However, summoning too many undead warriors at one time can cause him fatigue. As shown in The Blood of Olympus, when he is angered enough, Nico can destroy even undead warriors that aren't under his control, which he does with Bryce Lawrence's zombie troops. Whenever he needs a personal chauffeur, Nico summons Jules-Albert, a loyal French zombie.
 * Summoning Deceased Souls: as shown in The Battle of the Labyrinth, Nico can summon souls of the deceased by digging a pit, filling it with food (though animal blood can also be used), and chanting in Ancient Greek.
 * Releasing Souls: as shown in The Battle of the Labyrinth, Nico can release the souls of people that should have died but had somehow managed to cheat death, such as Daedalus.
 * Telepathy With The Dead: In The House of Hades, Nico warns the Lemures of Venice (angry spirits) to stay away from him, Hazel and Frank by giving off a warning vibe.
 * Sensitivity to Death: Nico can sense death as it happens or when it is coming; when a person close to him dies, it comes as a ringing in the ears. In addition to that, he has a deep knowledge of the Underworld and knows when a person's life is being judged in the Underworld. Nico can also sense when an immortal is fading, as in the case of Pan in The Battle of the Labyrinth. His powers are so great he could even sense that Percy and Annabeth were close to the Doors of Death within Tartarus.
 * Life Aura: Nico can sense someone's life aura (he sensed it when Rachel Elizabeth Dare's life aura flickered in The Last Olympian, and he told her, "I could see you dying."), and when Apollo became mortal in The Hidden Oracle Nico sensed an aura of death around him — "a thick possibility of death."
 * Seeing the Power of the Doors of Death:along side Hazel and Jason, Nico can see and feel the power of the Doors of Death.
 * Power Over Ghosts: as the Ghost King, Nico can physically manipulate ghosts, such as taking hold of them by hand or forcing them to be silent with a gesture.
 * Ghost Transformation: As seen in The Blood of Olympus, Nico can kill mortals, demigods and legacies by turning them into ghosts, and forcing them into the Underworld for eternity. Nico has only ever done this to Bryce Lawrence. However, this takes away a lot of his strength and may cause him to fatigue as he did after he killed Bryce Lawrence.
 * Osteokinesis: As seen in The Blood of Olympus, Nico is able summon and telekinetically to control bones. Prior to his fight with Lycaon in Évoria he could only summon a few bones and skulls. But during his encounter with the wolf king he was able to summon hundreds of bones, enough to trap Lycaon and his wolves for a few minutes showing that his abilities improve extremely quickly.
 * Death Trance: In The Mark of Athena, when he is sealed in the Bronze Jar, Nico shows that he can go into a hibernation called a Death Trance using the seeds of Persephone, which can only be eaten by a child of Hades. The Death Trance induces him to essentially die for a day, meaning he consumes no oxygen and doesn't need any kind of food (besides the seeds).
 * Umbrakinesis: Nico has control over darkness and shadows for various uses such as solidifying it for attacks and to hide in it.
 * Shadow Travel: Nico can use shadows as a way of transportation; however, great distances tend to wear him out. The first time he shadow traveled, he passed out for a week. He has said that while learning to use it, he ran into walls and made accidental trips to China. He seems to have gotten better control over it because in The House of Hades, he implied he could use shadow travel to send the Argo II across a mountain range, but was too weak because of his time in Tartarus. When he recovers his strength by the end of the The House of Hades, he decides to transport the Athena Parthenos across the ocean by shadow-traveling about three hundred miles at a time. However, as revealed in The Blood of Olympus, overexertion of shadow travel can cause the user's molecular structure to begin to fall apart, gradually turning them into shadows and lose themselves. Due to Nico pushing himself to bring the Athena Parthenos to Camp Half-Blood, he began to lose himself, even entering a "shadow coma".
 * Shadow Absorption and Dissipation: as shown during his fight with Clytius in The House of Hades, Nico can also dissipate and absorb shadows with his sword, since he kept the Giant's dark aura from affecting his friends.
 * Darkness Generation: He can shoot solid bolts of darkness, and surround enemies in pitch-black clouds of lightless space.
 * Darkness Shields: He can solidify shadows into virtually impenetrable shields.
 * Invisibility: He can use shadows to cover himself in darkness to become invisible.
 * Umbrakinetic Healing: He can heal himself and others using darkness (minor injuries).
 * Thermokinesis:Nico has been shown to generate extreme temperatures to the point of combustion and freezing. However he has yet to control the fire and ice he generates.
 * Cryokinesis (limited): As seen in The Blood of Olympus, when Nico is infuriated, he generates an aura of intense cold, making the temperature around him drop to freezing, with the ground around him and the massive cairn turning white with frost.
 * Pyrokinesis (limited): When Nico swallowed up the four skeleton warrior attacking him and Percy in The Titan's Curse, "flames erupted from the fissure."However, it is not known how powerful his control over fire actually is.
 * Hypnokinesis: as seen in The Blood of Olympus, Nico can navigate through "the dark dreamscape" of dreams better than most other demigods (and is only somewhat surpassed by demigod children of Hypnos, like Clovis), since he claims that dreams and death are "old friends of his." Hence, Nico has a higher degree on control over his dreams, the ability to astral project his consciousness, find and enter the dreams of other demigods. Reyna notes that Nico can have an extremely heavy sleep at times, to the point that he won't even budge if Coach Hedge does a goat-hoof tap dance around Nico's head. Later in the book, Nico puts several demigods to sleep by sending deep dreams their way.
 * Phobikinesis: Nico radiates an intense aura of fear and death like his father, Hades, but to a much lesser degree. In The Last Olympian, this aura was so strong that Kronos' monsters initially backed away from him. In The House of Hades, he is shown to radiate death from nervousness, as when Cupid intimidates him, "the grass turned brown and wilted" at his feet, as if "poison were seeping from the soles of his shoes." Even while he was still emaciated and weakened from Tartarus, even a demigod as brave as Jason Grace admitted to being afraid of Nico, possibly due to this fearsome aura in part.


 * -|Magical Items=
 * A Stygian iron sword. It is three feet long, and in The Last Olympian is described as being "black as a nightmare." It helps Nico to channel his power to control and summon the dead, and it can also drain souls to give the sword more power. Only Hades, his children and Clytius can use Stygian Iron for their weapons.
 * He is seen wearing black armor in The Last Olympian with a skull shaped visor.
 * A skull ring shown in The Battle of the Labyrinth, The Last Olympian, and The Son of Neptune. Twisting it makes the nearest dead restless. He usually uses it to relieve tension.
 * Mythomagic figurines and cards. He throws them into a fire in anger during The Battle of the Labyrinth.
 * In The Battle of the Labyrinth, he had a pair of Daedalus' wings, but after he used them, he threw it away in a trash can.
 * A red travel rose that he didn't use, given to him by Persephone, in The Sword of Hades.
 * Pomegranate Seeds - magical seeds from Persephone's Garden in the Underworld. If he places them on his tongue, he can go into a death like trance that allows him to use less air and energy, in the event he is captured. This allows him to go into what is called a "Death Trance," which he uses to sustain himself during The Mark of Athena.
 * Diocletian's Scepter: Nico obtained the scepter after he confessed his feelings for Percy, the scepter allows him to summon zombie legionnaires to his aid - he can not control them however, as his is neither a Roman demigod nor a Roman officer. He used the scepter to summon zombies at the Necromanteion and Pompeii to fend off Gaea's forces, after which it exploded.

Love Interests
Percy Jackson=

"But it's cool. We're cool. I mean, I see now . . . you're cute, but you're not my type."

- Nico di Angelo to Percy Jackson

Young Nico had the ability to annoy Percy quite easily, as seen in The Titan's Curse when he asked Percy several questions about his relationship with Annabeth. Nico developed a secret but very strong crush on Percy, as he was "Nico’s favorite game, Mythomagic, brought to life." Near the end of the book however, Nico begins to blame Percy for his sister's death, making him much more cynical, but still doesn't let the Skeleton Warriors harm him, and "leaves Camp Half-Blood because of love". Nico later claims that realizing his crush would plague him with self-hatred and resentment for Percy. Percy, true to character, feels partially at fault and responsible for Nico leaving.

In The Battle of the Labyrinth, Percy receives Iris Messages from Bianca regarding Nico. The two later meet at Geryon's ranch, where Percy makes a bet with Geryon. Nico is included, which angers him, as he shouts that he doesn't want any favors from Percy. After Percy defeats Geryon, he and Nico talk to Bianca, who tells Nico to stop holding a grudge against Percy when it is she he is angry with. By the end of the book, Nico has forgiven Percy. In the last chapter, he appears and informs Percy of a plan he has.

In The Last Olympian, Nico leads Percy to his father's palace in order to gain information on his mother, not knowing that Hades plans to lock Percy up. Percy feels betrayed, even when Nico eventually tries to help him. After Percy bathes in the Styx, he tells Nico to stay and convince Hades to join the Olympians in battle. Nico appears glum, stating that Percy can't trust him anymore. The two join to battle in final battle and Percy forgives Nico. It is later revealed that when Nico planned to get Percy to bathe in the River Styx, he had hoped that this would make Percy fall in love with him.

After Percy has lost his memory in The Son of Neptune, Nico pretends to not know him, and it's later revealed in The Mark of Athena that Hades had told him the time was not right for Percy to know. Once Percy regains his memory, he feels the urge to strangle Nico for not telling him.

In The Mark of Athena, in Percy's narration, it is mentioned that Percy had wanted to strangle Nico about what he did, but doesn't, due to how Nico is after being kidnapped. Nico states (after Annabeth and Percy's fall) that Percy is the most powerful demigod that he knows. During Nico's kidnapping, Percy doesn't give up on finding him, showing that he cares a lot about him. After Nico is rescued Percy can tell that Nico may or may not have seen something in Tartarus that shattered him permanently, which shows that they know each other well, despite their previous situations.

In The House of Hades, Nico's true feelings towards Percy are finally revealed when he is forced to admit that his feelings for Percy run deeper than friendship, as he had a crush on Percy. Jason is with him at the time and keeps the secret for him. Percy knows nothing of these feelings and does not return them, though he does care for him like a brother and while in Tartarus realizes Nico is another friend he hasn't treated very well. At some point, Nico had visited Iapetus in the Underworld, and told him that Percy was a friend. It is more than likely that Nico assisted Percy multiple times in the past due to the crush he had on him. For instance, it is later revealed that when Nico planned to get Percy to bathe in the River Styx, he had hoped that this would make Percy fall in love with him.

Although Nico states in The House of Hades that he gave up on Percy, there are several parts in the book that imply otherwise. Favionus calls Percy, though not by name, "the one [Nico] cares for most," and Hazel notices that Nico has a pained look in his eyes at seeing Percy and Annabeth hold hands. However, because she doesn't know of Nico's crush on Percy, Hazel believes that the pain is from Nico having gone through Tartarus alone.

When Nico and Hazel Shadow Travel the group out of the Necromanteion, Nico realized that he was holding Percy's hand after everybody else let go, and quickly lets go. Later on, when Nico goes to transport himself, Reyna, and the Athena Parthenos, Percy comes to thank him for keeping his promise and tries to pick up their tattered friendship, Nico, afraid of his feelings, asks Percy to give him space and leave him alone, much to Percy's confusion and hurt.

In The Blood of Olympus, Nico sees Percy and Annabeth together, laughing. He approaches the couple and tells Percy that he previously had a crush on him, but that he's over him. He states that he's happy for the two and Percy seemed to be fumbling for his words. He continues and announces, that they're cool. He calls Percy cute but says that Percy is not his type. Once the confrontation was over, Nico received a high-five from Annabeth.

In The Blood of Olympus, it's hinted that Nico has developed an attraction to Will Solace, as they fought alongside each other. The two argue, but Will is shown to be able to withstand Nico's temper, and even order him around a bit. Nico develops an admiration for Will, who he hadn't thought greatly of before. At one point, Nico remembers his first arrival to camp in Apollo's sun chariot, and how Thalia had thought that Will's divine father was hot. While Nico didn't understand suddenly remembering this, it is most likely an indication of his budding feelings for Will, since Will is Apollo's son and shares physical traits with him. In the aftermath of the battle, Nico avoided Will, believing he was disgusted with him for allowing Octavian to kill himself, showing he cared very much about Will's opinion of him. To his surprise, Will is more upset that Nico didn't offer to help him, or more importantly, spend time with him after it was all over. Will ordered Nico to stay with him in infirmary for three days, and Nico "felt like a hundred skeletal butterflies were resurrecting in his stomach". Will also seems to reciprocate said feelings, or at the very least, is willing to be closer friends with the son of Hades.
 * -|Will Solace=

In The Hidden Oracle it is revealed that shortly after Gaea's defeat, Nico finally comes out and confesses to Will Solace about having a strong crush on the latter, and the two begin dating, with Will at one point affectionately referring to Nico as his boyfriend. Will's father, the former god Apollo, is completely supportive of their relationship, due to him having had several mortal boyfriends himself. They continue their playful banter with each other, and are usually seen sitting close by, holding hands. In fact, Apollo claims that Nico and Will are so cute together as a couple, that it made him feel desolate, jogging his memories of the time he had spent with his mortal boyfriend Hyacinthus, one of Apollo's two all-time favorite lovers (the other being Daphne). Nico on his part, is always ready to help and support Will, such as when he tirelessly helped his boyfriend tend to wounded campers (notably Paolo Montes and Valentina Diaz). Nico also showed some jealousy when he caught Will staring at Paolo, but Will stated that it was nothing and that he was merely admiring how well his arms were functioning after surgery.

Friends
Annabeth Chase= While their friendship is not mentioned extensively, Nico respects Annabeth and is at times shown to listen to her more than Percy, possibly to annoy him. However, in The Battle of the Labyrinth, his view of her improved to the point of friendship, as he chose to save not only Percy, but Annabeth as well when he named himself the Ghost King.

In The Mark of Athena, it is revealed that Annabeth has always had mixed feelings about Nico di Angelo, and suspects that he had a crush on her. However, Annabeth herself has no feelings for him beyond kinship, since he is too young, too moody, and has a certain darkness in him that makes Annabeth uneasy. Furthermore, she has always found it hard to "read" Nico and his actions. However, Annabeth still admits to feeling responsible for him, and can relate to feeling like Nico did after Bianca's death—a homeless orphan, drifting through the world alone.

In The House of Hades, it is finally revealed that Nico was actually jealous of Annabeth, not in love with her, due to her relationship with Percy (his actual love interest), which is why Nico initially didn't want to be around her. After seeing Annabeth and Percy holding hands, Nico looks pained, showing that his secret crush on Percy is as strong as ever.

In The Blood of Olympus, it is revealed that after her return from Tartarus, Annabeth went out of her way to thank Nico for being nice to Iapetus (even before Percy did so), and telling the Titan that Percy is worth saving. While Nico is still very jealous of Annabeth, and wants to hate her, he cannot bring himself to, since Annabeth's gratitude was genuine and sincere, and she never overlooked or avoided Nico like most people. Hence, Nico admits to himself that it would have been far easier for him if she were a horrible person. Later in the book, when Hades reveals to Nico that one of the Seven is destined to die, the idea of any of them (even Annabeth) dying made him feel empty—like he was back in the dark Giants' Bronze Jar. By the end of the book, Nico finally finds the courage to tell Percy and Annabeth about his past crush on Percy, coming out for the first time. By that point, however, Nico has come to realize that Percy is not his type, and that he is genuinely happy for Percy and Annabeth. While Annabeth is certainly shocked at such an unexpected revelation from Nico, she smiles at the son of Hades and high-fives him.

Before meeting him in The Mark of Athena, Leo voices his doubts about Nico's loyalties, infuriating Hazel. Later on, after meeting him, Leo considers Nico creepy, unlike Hazel. They have not gotten to know each other yet, but seem to be on good terms so far, as when Leo is overwhelmed with guilt about not saving Percy and Annabeth, Nico comforts him and assures him that they are alive.
 * -|Leo Valdez=

In The House of Hades, Nico seems annoyed with Leo's frustration about constantly rebuilding the masts, saying that they don't grow on trees. Nico corrects him by calmly pointing out that they are made from trees. Leo is very much intimidated by the son of Hades, and never dares to tease him to his face. Nico, being far more serious, is frequently annoyed by Leo's sense of humor. After Leo returns from Calypso's island, Nico is glad to see him, and shakes his hand.

In The Blood of Olympus, when Hades reveals to Nico that one of the Seven is destined to die, the idea of any of them (including Leo) dying made him feel empty—like he was back in the dark Giants' Bronze Jar. Nico is quite saddened by Leo's death, does his best to comfort Hazel about it, and prays to his father for guidance.

In The Hidden Oracle it is revealed that a resurrected Leo was able to send a parchment scroll with a holographic message several days after his and Gaea's deaths. While almost all of the campers are both exuberant and furious, Nico is affected more deeply than most (due to him having blamed himself for Leo's death), and therefore he keeps the scroll in his pocket long after other campers had finished re-listening to it, and he resorts to looking at it whenever he wants to get angry at Leo. When Leo finally returns, Nico is in charge of having the other demigods get in line to both punch and greet the returned son of Hephaestus, with Nico being the last one to do so.

Interestingly, some things that Nico and Leo have in common, is that they both fluently speak a Romance language (Italian and Spanish respectively), they have both witnessed their mothers' deaths at the hand of a deity (Zeus and Gaea respectively), they have both had an embarrassing experience in Albania, and they have both run away from places they used to call home (Camp Half-Blood and multiple foster homes respectively).

While Nico is kind of mysterious and makes everybody else nervous, Frank doesn't feel the same way and may trust him because of Hazel, as he does not doubt Nico's loyalties in The Mark of Athena, unlike Jason and Leo. Nico, on his part, finds Frank amusing, as stated in The Son of Neptune.
 * -|Frank Zhang=

In The House of Hades, it is revealed that Frank had always feared Nico, and wasn't sure what scared him more: hordes of restless ghosts or going somewhere alone with Nico. However, after Hazel gets poisoned, Frank is furious with him for not being able to prevent it. Nonetheless, when Triptolemus turns Nico into a maize, Frank does his best to save him as well as Hazel, and even slams Triptolemus into a wall for not transforming Nico back. When they reach the Necromanteion, Nico and Frank work well as a team to control an army of undead warriors and defeat Gaea's minions. After they succeed, Nico smiles at him, much to Frank's surprise. They have both played Mythomagic before, though Nico's knowledge of the game is superior, as he had the Africanus Extreme expansion deck. Another thing they have in common is their love for Hazel.

In The Blood of Olympus, when Hades reveals to Nico that one of the Seven is destined to die, the idea of any of them (including Frank) dying made him feel empty—like he was back in the dark Giants' Bronze Jar. Near the end of the book, Nico approves of Frank's relationship with Hazel, and promises to visit them often at Camp Jupiter.

"Easy for you to say. You're everybody's golden boy, the son of Jupiter."
 * -|Jason Grace=

- Nico di Angelo to Jason Grace

Jason had meet Nico at Camp Jupiter at once point. Before rescuing him in The Mark of Athena, Jason voices his doubts on Nico's loyalties, infuriating Hazel.

In The House of Hades, Jason is the only one who finds out about Nico's crush on Percy and agrees to keep it a secret. His behavior towards Nico also changes after this revelation, and he acknowledges Nico's courage and later defends Nico when Leo calls him creepy. However, when Nico gets infuriated with Jason for telling him to come out, he admits to having seen many angry demigods, but "an angry son of Hades seemed more than he could handle." However, when they reach the Necromanteion, the first person Nico gives the chalice to is Jason, asking him to trust him and take a risk, which implies that he has forgiven Jason and is finally considering to take the risk of coming out. Their rocky relationship corresponds to the one between Zeus and Hades.

In The Blood of Olympus, when Hades reveals to Nico that one of the Seven is destined to die, the idea of any of them (including Jason) dying made him feel empty - like he was back in the dark Giants' Bronze Jar. In fact, Nico's primary concern (after his sister Hazel) was for Jason. After Nico finally decides to stay at Camp Half-Blood, Jason is so excited to hear it, that he gives the son of Hades a bear hug, which Nico returns.

"You're the most courageous demigod I've ever meet, Reyna. I—I won't let you down."
 * -|Reyna Avila Ramírez-Arellano=

- Nico to Reyna

Through their relationship is not directly shown in The Son of Neptune, it can be concluded the they are on good terms. They have obviously interacted before, with their first encounter being when Nico asks her to accept his sister, Hazel, into the legion. Back in Camp Jupiter, Nico was a Senator and the Ambassador of Pluto, and therefore possibly involved in the camp's political life along with her. At the end of The House of Hades, Reyna is willing to travel with Nico under very dangerous circumstances, showing that she at least does not doubt the son of Hades' loyalty.

In The Blood of Olympus, the two grow close over the course of their journey. Reyna lends Nico strength to shadow-travel, and, as a result, she learns quite a bit about his past and the tremendous internal pain that he's been harboring. She is horrified at the amount of internal turmoil, and is determined to support him, and starts thinking of him as a younger brother in spite of herself. Eventually, the two open up to one another, as Reyna describes how she killed her father in Puerto Rico (something she'd never told anyone up to that point), and Nico his issues with his father, how he suffered through Tartarus and the feeling of not belonging at either camp. Also, Reyna is the first person that Nico tells about Jules-Albert, his French zombie chauffeur.

Reyna later witnesses him kill Bryce Lawrence and seems horrified at the ferocious display of Nico's infernal powers. At that moment, Nico accidentally generates a "flood of pain and anger" on everyone present, allowing Reyna to finally experience his hardships from his point of view and also see Nico's greatest fears and secrets (including his homosexuality and his crush on Percy). Much to Nico's surprise and relief, however, Reyna doesn't judge him, still accepts him as a friend just as he is, without hesitation, and cares for Nico's wounds while he recovers from his encounter with Bryce.

In addition, Reyna appears to be in awe of Nico's powers, especially after learning that he also possesses hypnokinetic abilities. Nico, in turn, respects Reyna quite a bit, and by the end of their journey to Camp Half-Blood, he even calls her the most courageous demigod he'd ever meet.

After Gaea's defeat, Reyna tells the two camps about Nico's part in saving both of them, brings him out of the shadows, gives him a big hug, and he tearfully returns it, burying his face in Reyna's shoulder. The crowd of demigods roars with approval in response, indicating that thanks to Reyna, both Camp Half-Blood and Camp Jupiter have finally come to truly accept the son of Hades. Shortly before leaving Camp Half-Blood, Reyna promises Nico that he will always have a place in New Rome, and he promises to visit often.

Interestingly, three things that both Nico and Reyna have in common are them both fluently speaking a Romance language (Italian and Spanish respectively), their tendency to hold grudges (though Nico has improved in this regard considerably), and their unrequited feelings for Percy in the past, but have both managed to move on since then, while remaining good friends with the son of Poseidon.

Nico and Piper first meet in The Mark of Athena, after he is rescued. Though no formal interaction is seen between them yet, Nico is definitely thankful to Piper for personally dragging him to safety after he falls out of the Bronze Jar. Like her friends, Piper is very much intimidated by the son of Hades. In The Blood of Olympus, when Hades reveals to Nico that one of the Seven is destined to die, the idea of any of them (including Piper) dying made him feel empty—like he was back in the dark Giants' Bronze Jar.
 * -|Piper McLean=

There is not much known about their relationship. In The Sword of Hades, Thalia only seems to know him as Bianca's little brother and refers to him as such. Nico dislikes being called that, but he seems to be on good terms with her, even though he generally dislikes the Hunters of Artemis. Nico and Thalia have worked well together as a team when they fought the Titan Iapetus with Percy.
 * -|Thalia Grace=

Family
Hazel Levesque= "You’re my sister too. You deserve another chance. Come with me."

- Nico to Hazel

In The Son of Neptune, Nico is shown to be very caring to Hazel Levesque, his half-sister, and tries to help her as much as he can. Nico occasionally mistakes her for Bianca, which often reminds Hazel that she isn't the one he was looking for when he entered the Fields of Asphodel. Despite this, the two care deeply for each other, and refer to each other as "brother" and "sister". Nico is one of the few people who know about Hazel's past and was the one who helped her during her blackouts, which shows that he loves his family, even his half-siblings.

The two represent the aspects of Hades and Pluto's realms respectively, as in Greece, Hades was known for death and in Rome, Pluto was known for his wealth. Hazel remarks that before she met Percy, Nico was the strongest demigod she had met even though the Romans thought he was harmless. Near the end of the book, Gaea informs Hazel that she has taken Nico and that he should not have gone looking for the Doors of Death.

In The Mark of Athena, when Jason and Leo express doubts about Nico's loyalty, she gets incredibly furious. She was also determined to go to Rome to save Nico despite knowing it could be a trap. After Nico is saved and she sees his broken state, Hazel tries her best to comfort him.

In The House of Hades, when Hazel is dying of poison, Nico goes as far as threaten a minor god to heal her, which results in him being turned into a plant. Later, he kisses Hazel on the cheek as if saying goodbye, to the surprise of Piper. After rescuing Hazel from a giant at the Doors of Death, Nico comes over and kisses her forehead and claims that Hazel 'would have made Dad proud', this sentimental compliment may have reminded Nico of his sister Bianca, who Hades initially considered better than him in every way. Hazel cups her hand around his face and smiles at him, showing they have a very close relationship. She thinks herself very lucky to have a brother like Nico. Still, even she knows nothing about Nico's love for Percy. In The Blood of Olympus, when Hades reveals to Nico that one of the Seven is destined to die, Nico's primary concern is for Hazel. At the end of the book, before Hazel and Frank depart for Camp Jupiter, Nico promises to visit them often.

"I love Nico—don't get me wrong—I just needed to find out what it would be like not to be a big sister twenty-four hours a day."
 * -|Bianca di Angelo=

- Bianca about Nico

Nico and Bianca shared a very close relationship. As their mother died when they were young, Bianca assumes an almost motherly role, bearing the responsibility that a parent would normally bear, shown when Nico stated Bianca is strict on the movies she lets him watch before he watched the Orientation Film. This is one of the reasons why Bianca joined the Hunters of Artemis. In The Titan's Curse, Bianca tells Percy that she wanted to know what it would be like to "not be a big sister for one day." Nico felt betrayed when this happened and managed to convince Percy to follow her and keep her safe for him. When Percy failed to do so, Nico was angered and claimed that he could feel her soul being judged, causing Percy to realize he is a son of Hades.

In The Battle of the Labyrinth, Nico is shown to be attempting to bring Bianca back to life through the exchange of a soul for another soul. In search for this soul, Nico meets Percy at Geryon's ranch. Percy tells him that Bianca has been sending him Iris Messages, which angers Nico, as she refuses to see him. Later, Bianca appears. She tells Nico to stop holding a grudge against Percy and it is she that Nico is angry at her, not Percy. Later in the book, Nico is seen talking to Bianca again.

She appears once in The Last Olympian, attempting to dissuade Nico from summoning their mother. Her warning goes unheeded.

In The Son of Neptune, it is mentioned that Nico goes searching for Bianca when Thanatos is kidnapped but finds that she has been given rebirth. Instead, he finds Hazel and brings her back to life.

In The House of Hades, when Jason discusses his revelation to Cupid, Nico angrily tells him that Bianca was the only one who accepted him. Whether this is referring to the fact that he feels like an outcast because he's a son of Hades or whether Bianca knew that Nico was gay is unclear.

"Nico and Bianca need their mother . .."
 * -|Maria di Angelo=

- Maria di Angelo about her children

Nico has no memories of his mother, which is why he is so eager to discover more information from Hades, who uses this to his advantage at times. He attempts to summon her, despite Bianca warning him that he should not.

In his attempt to summon his mother, he is presented a memory which discusses the terms of the agreement after World War II and how Hades defied it. Nico watches as Hades and Maria discuss how Hades can bring her to safety, though his offer of building her a palace is declined. He then sees Zeus destroy the hotel they were staying in in an attempt to kill him and Bianca.

"My son, whatever happens, you have earned my respect. You brought honor to our house."
 * -|Hades=

- Hades to Nico

Nico and his father share a complicated relationship. They are both extremely similar, especially in their ability to hold grudges. Both of them are also somewhat cynical. However, Nico seems to have a stronger tie to his friends, while Hades seems to have a much darker view of his siblings. Nico is also a more genuine person than his father- Hades can be crafty, as seen from how he used Nico to attempt to trap Percy.

Hades occasionally remarks that it would've been better if Bianca survived, much to Nico's dismay, though deep down, he cares a great deal for his son, as his gaze softened "from steel to stone" when he saw him. He also wants to redeem himself in the Olympians' eyes through Nico, believing his son to be the demigod of the First Great Prophecy. Nico also appears to want to please his father, and beams with happiness when he gains Hades' respect after Kronos' defeat. At the same time, Nico is unafraid to challenge his father in order to do what Nico believes is right.

After the Battle of Manhattan, Hades begins trusting Nico with much more information, and even tells him about Camp Jupiter and the Roman demigods, trusting Nico not to share this knowledge with anybody else until the time is right. Hades might have foreseen that Nico was destined to find the Doors of Death and lead the Seven Heroes of Olympus there.

In The Blood of Olympus, Hades and Nico speak in Évora. Hades tells Nico that "some deaths cannot be prevented" which alluded to Octavian's death. Hades also praises Nico for his past accomplishments, letting him know that he is proud of his son, and that he wants Nico to be happy. Their relationship seems to have improved, since Hades' tone is described as "almost gentle" while he is taking to his son, while Nico (who usually dislikes being touched), feels reassured when his father briefly touches his shoulders. It is later revealed that Hades gave Nico a zombie chauffeur as a birthday present once, since he was trying to be more like normal mortal parents, who normally drive their children to places.

Nico and his stepmother Persephone mutually dislike each other, as he is a reminder of Hades' affair with Maria di Angelo, who Persephone is jealous of. This same dislike appears between Percy and Amphitrite, as well as Thalia and Hera. Persephone appears to take it to another level through turning Nico into a dandelion as stated by him in The Demigod Files when Percy, Thalia, and he ended up in the Underworld together.
 * -|Persephone=

In The Mark of Athena, it is revealed that Nico carries around some pomegranate seeds from Persephone's garden in case of an emergency, and so uses them when he is trapped by the twin giants. It is unknown how Persephone feels about Nico using an item from her personal garden, or if she is aware at all.

Others
Shortly after Nico initially ran away from Camp Half-Blood, he was found in the Labyrinth by the ghost of King Minos, who intended to manipulate the son of Hades into killing Daedalus in revenge for his unjust, however much deserved, death. In order to gain Nico's trust, Minos leads him through the maze of the Labyrinth, saved him multiple times, and taught him how to utilize his infernal demigod powers. It is most likely that Minos was also the one to teach Nico to shadow travel. In the end, however, Nico realized Minos' malevolent goals, and banished him back to the Underworld, stripping him of his Ghost King title, and taking it for himself.
 * -|King Minos=

Years later, in The Blood of Olympus, Nico has several flashbacks of Minos in his dreams. It is also revealed that Nico's experience with Minos made him realize that most specters held only as much power as one allows them to. Hence, the son of Hades has learned to shield himself from specters' influence, and can even turn the tables now, bending them to his will.

"Some dogs need to be put down, like you!"
 * -|Octavian=

- Nico to Octavian

As seen in The Son of Neptune, Octavian, much like most others at Camp Jupiter, thinks of Nico as just a somewhat creepy traveling outcast, considering the Ambassador of Pluto to be as harmless as a Faun. However, Octavian does grow suspicious when Nico seems to know about Alcyoneus in the meeting.

By The Blood of Olympus, Nico comes to absolutely despise the self-proclaimed Pontifex Maximus (to the point that his throat "constricted with hate" while just thinking about Octavian), and even considers personally assassinating Octavian without any qualms. Nico notes how different Octavian is from his love interest Will Solace, and describes the former as looking like a watered-down, unhealthy version of Will, without anything in him that makes a child of Apollo special. Octavian, on the other hand, seems to have finally come to appreciate what a powerful ally Nico could potentially be for him, as he claims to see a decent amount of ruthlessness in the son of Hades, which he also greatly appreciates. Hence, Octavian promptly attempts to sway the son of Hades to his side, arguing that the Greeks hadn't ever actually done anything for the former. Octavian claims that he can beat any offer the Greeks might have given Nico, and assures him a place in New Rome in return for Nico siding with him and allowing the Romans to win. Nico, however, does't even consider the offer, declines right away, and promptly tells all of the assembled demigods to listen to what Reyna has to say, just as she arrives with the Athena Parthenos in tow. Nico is later present when Octavian intends to shoot an onager at Gaea, and clearly sees that doing so will result in Octavian's death. However, it is at that moment that Nico recalls what his father Hades had told him, about some deaths that cannot and should not be prevented, and Nico needing to act when the time comes. Hence, for the first time, Nico decides to trust the wisdom of his father, and stops Will (who stares at him in disbelief) from trying to prevent Octavian's plan, and subsequently witnesses the augur's horrific fiery demise, along with the death of Leo and destruction of Gaea. While Nico isn't at all saddened by Octavian's death, he is very guilt-ridden, since Nico feels that him choosing not to prevent Octavian's death unnecessarily cost Leo his life, something that he is unable to forgive himself for. Nico is also horrified of Will now possibly thinking of him as a monster for letting Octavian die, but is extremely relieved to learn of that not being the case.

After the Titan Iapetus lost his memory, Nico would visit him at his father's palace. He would convince Bob that Percy was a good person, which would eventually lead to the Titan helping Percy and Annabeth reach the Doors of Death from inside Tartarus.
 * -|Iapetus/Bob=

Nico does not care for Artemis' immortal handmaidens, since his sister died shortly after joining. He feels that the girls who do join should be more aware of what they are getting themselves into. When he awoke in San Juan and saw the note they left, he tore it up in a fit of rage. Despite fighting alongside Thalia before, he still has mixed feelings for her, mainly because she is the lieutenant of Artemis, and continued recruiting after Bianca died.
 * -|Hunters of Artemis=

Etymology

 * The name Nico is the diminutive form of Nicolò or Nicola, the Italian form of the Greek Nikolaos (Nicholas), meaning "victory of the people." It is most likely intended to evoke the prefix necro-, meaning dead. With his surname di Angelo being Italian for "of the angels", the full meaning of his name would thus be "angel of the dead", alluding to his role as the Lord of the Dead's son.
 * Nico is also a form of the Greek Nike, meaning "victory".

Trivia

 * The line "With great power . . . comes great need to take a nap." is an obvious reference to one of Spider-Man's most famous lines: "With great power, comes great responsibility", albeit a bit altered for comedic effect and to indicate that Nico's powers tire him greatly, prompting him to take naps every now and again to regain his strength, as he did at that moment in The Last Olympian.
 * Nico's physical description (pale olive skin, dark hair, brown eyes, black clothes, and an aura of death) also fits Rick Riordan's description of Anubis, the Egyptian god of funerals, in The Kane Chronicles trilogy.
 * The first time he met Mr. D, he called him "The wine dude", which irritated the god, but he forgot about it soon after.
 * Nico has been shown to be a solitary type of person, but he has a certain way of communicating with people. He was the first demigod in years to notice the goddess Hestia and speak with her, he convinced his father Hades to fight in the Titan War when no one else could, and he alone convinced the Titan Bob to save Percy and Annabeth.
 * Nico has been to a New Orleans graveyard, though it is unknown why he went. Interestingly, this is one of the favorite hangouts of Anubis. It was also the place that his half-sister Hazel Levesque lived just before her death.
 * Nico and Jason Grace have similarities:
 * They both have older sisters, whom have both been/are Hunters of Artemis.
 * They have both been to Camp Half-Blood and Camp Jupiter.
 * They have godly stepmothers (Persephone, Juno).
 * Both have lost their memory. Nico's because of being dipped in the River Lethe and Jason's was removed by Juno (though Jason's is temporary; in The House of Hades he seems to be recovering from his amnesia, much like Iapetus).
 * Hazel Levesque and Nico's mothers share similar first names: Marie Levesque and Maria di Angelo.
 * Nico's birthday is undecided. Rick Riordan has stated on two different occasions his birth-date: January 28th, 1924 and May 16th, 1924. However, the year would be way off since in The Son of Neptune, Hazel stated he was only a few years younger than her. Another contradiction comes from The House of Hades where in Nico mentioned that he was about six years old when he first visited Diocletian's private residence in "[nineteen] thirty-eight or so". This would put his date of birth at around the early 1930s.
 * In the series, he is described as having long, shaggy black hair, but in his earlier portrait he has short brown hair. Also, he seems to have green eyes instead of brown, and not as pale of skin. A more recent portrait shows a more accurate image of him to the story.
 * He is the only child of the Big Three to never have gone on an official quest in either series. However, Nico, Percy, and Thalia were given the task of retrieving the then unfinished sword of Hades, and succeeded. He also aided the Seven Heroes of Olympus in closing the Doors of Death and helped Reyna bring the Athena Parthenos to Camp Half-Blood to end the impending civil war.
 * Unlike his half sister Hazel, horses don't like Nico (as Porkpie, one of Blackjack's friend once stated: "He smells like dead people.")
 * Most animals don't like Nico due to him smelling like death, and the feeling is often mutual.
 * Nico speaks fluent Italian, as he is Italian by birth. (It should be noted, however, that he had his memory wiped in the River Lethe. It is possible, though, that he picked up the language sometime between The Last Olympian and The Son of Neptune.)
 * Nico has the ability to control ghosts. However Melinoe is the goddess of ghosts, not Hades.
 * As of The Titan's Curse, Nico is the only known demigod that is confirmed to have watched Camp Half-Blood's Orientation Film.
 * As of The Last Olympian, Nico is the first demigod in many years known to have stopped by and spoken to Hestia, who is usually ignored when she visits Camp Half-Blood.
 * As of The Son of Neptune, Nico is the first known Greek demigod since the First Demigod Civil War to learn about the existence of Roman demigods, and to visit Camp Jupiter.
 * Nico is the only known Senator at Camp Jupiter that was neither a Centurion nor a Praetor, instead serving as the Ambassador of Pluto.
 * As of The Mark of Athena, Nico is the first known demigod ever to have returned from Tartarus alive but even as a son of Hades, his stay in Tartarus left him shattered, irascible, and even more withdrawn than usual.
 * Percy speculates, when on the verge of death and seeing Tartarus as it really is, that Nico had seen it that way the whole time, and that even a few moments of seeing it was maddening. He wonders how Nico had survived with his sanity. Nico himself stated it nearly drove him insane.
 * As of The House of Hades, Nico is the only known demigod that Leo, Frank and Jason are afraid of.
 * Nico has been transformed into plants twice in the series: into a dandelion by Persephone during a "family spat" shortly before the The Demigod Files, and into a corn plant by Triptolemus in The House of Hades.
 * Nico is the first confirmed LGBT demigod (with Will Solace and Alex Fierro being later confirmed to be as well, in The Hidden Oracle and The Hammer of Thor respectively), something he has been trying to hide for years. The only blatant clue is in The Titan's Curse, when he asks Percy if Annabeth is his girlfriend. Jason believes that Nico's hiding of this has to do with Nico being from the 1940s, where homosexuality wasn't accepted.
 * Hence, as of The Hidden Oracle, Nico and Will are the first gay couple shown in the series.
 * As of The Blood of Olympus, Nico is the only known hypnokinesis user that is not a child of Hypnos.
 * In both the Percy Jackson and the Olympians and the The Heroes of Olympus series, Nico ensures the fulfillment of the Great Prophecies: Nico helps Percy gain the Curse of Achilles, which enables both Percy and Luke to defeat Kronos ("the hero's soul cursed blade shall reap"), and Nico tells Iapetus that Percy is a friend, which induces him to follow Percy and Annabeth to the Doors of Death ("foes bear arms to the Doors of Death").
 * Hades once gave Nico a French zombie chauffeur, Jules-Albert, for his birthday.
 * When he was little (even before he became interested in Mythomagic), Nico was obsessed with pirates.
 * In The Titan's Curse, Nico is ten and Percy is fourteen, there is a four-year age difference. In The Hidden Oracle, Nico is fourteen and Percy is seventeen, turning eighteen in August.
 * Nico is mentioned in the Lightingh Thief Musical by Bianca Di Angelo.