Jason Grace

For other uses of the name Jason, see Jason (disambiguation).

"I'm the son of Jupiter! I'm a child of Rome, consul to demigods, praetor of the Twelfth Legion. I slew the Trojan sea monster, I toppled the black throne of Kronos and destroyed the Titan Krios with my own hands. And now I'm going to destroy you, Porphyrion, and feed you to your own wolves."

- Jason to Porphyrion

Jason Grace is a Roman demigod, the son of Jupiter and the mortal Beryl Grace and the younger brother of Thalia Grace. He was a praetor at Camp Jupiter until he gave his rank to Frank Zhang; he is the current head counselor of Cabin One at Camp Half-Blood, being the only one there. He is in a relationship with Piper McLean. He is also the present Pontifex Maximus at Camp Jupiter.

History
Jason was born on July 1; the son of Jupiter, the Roman aspect of Zeus, and the mortal actress Beryl Grace. He was born seven years after Zeus fathered Thalia. Because his father had consecutively sired two children with his mother, Juno, the Roman form of Hera, was made Jason's guardian to placate the indignant goddess, as Jupiter went so far as to name his newborn son after his wife's favorite hero, Jason, in the attempt to appease his wife for his infidelity.

When Jason was young, Juno commanded his mother to bring him to the Wolf House. It was then that he was separated from his mother and sister to be initiated by Lupa in the ways of Rome. After training for some time under the she-wolf, he journeyed to Camp Jupiter where he was raised in the lifestyle of the Roman Legion. Eventually, Jason was inducted into the Fifth Cohort and would begin restoring a sense of honor to the disgraced contingent. When he was a centurion of the Fifth Cohort, his cohort would get jobs such as clearing out the basilisks from under Temple Hill. Few details are known about the quests Jason went on during his days at Camp Jupiter, however some of his accomplishments include leading a quest to find and slay the Trojan sea monster, which included him staying at Aeolus's palace for a few days, doing a favour for the god Bacchus involving a missing leopard in Sonoma, and going on a quest with Reyna to Charleston to retrieve a stash of Imperial Gold torpedoes from the C.S.S. Hunley at Fort Sumter.

While the Greeks were fighting Kronos and the main Titan army in the Battle of Manhattan, Jason and Reyna led the Twelfth Legion in an assault on Mount Othrys where he fought through an army of Scythian dracanae and defeated the Titan Krios himself. His actions, which resulted in the destruction of Mount Othrys, led the members of the legion to raise him to the rank of praetor.

The Son of Neptune
Jason is mentioned several times by the campers of Camp Jupiter, because they've been wondering where he has gone. Percy has a brief dream of Leo working on the Argo II with Piper and Jason behind him. As well, when Percy, Frank, and Hazel are watching Polybotes from afar Ma Gasket yells, "The camp, yes. Vengeance! The orange and purple ones destroy my home. Now Ma Gasket will destroy theirs," referencing how Jason destroyed her factory. After returning from their quest and saving Camp Jupiter, Leo sends a video scroll to ask for safe passage from the Romans. While Percy tries to tell them that they won't attack, he tells them that Jason is on board the ship, leading Reyna to allow the ship to land, but not without any kind of security.

The Mark of Athena
At the beginning of the book, Jason is on the Argo II, along with Annabeth, Leo, Gleeson, and Piper, his girlfriend. He is seen wearing a Camp Half-Blood T-shirt with a purple toga over it, while holding a sword.

When the five arrive at New Rome, Reyna greets them and they hold a discussion outside of the camp. Jason introduces all of the members aboard except for Coach Hedge who is on the ship. During the discussion they discuss about who the seven are and Jason's adventure's at Camp Half-Blood. After the discussion, Jason asks Reyna if he could show Piper around New Rome. Reyna allows Jason to do so. When the Argo II starts firing, Annabeth spots Jason and Piper in the middle of a crowd of Romans who are throwing plates and stones at them. Frank however is able to save them after forming into a dragon and they escape onto the ship. Before they could escape Jason is knocked out from a stone thrown at his head.

Jason is unconscious, while the rest of the seven, save for Piper, look for items for the wrecked ship. Jason wakes up as Piper is telling the group they need head to mile marker Topeka 32. Piper explains that she saw a man with a silver goblet. Jason recognizes him as Bacchus and says that he did him a favor in wine country a few years back, accompanying Piper and Percy to meet him. The trio walks about a mile to the nearest mile marker and realize that Leo dropped them off further than they could walk. Percy and Jason have a contest to see who's companion can come the faster. Percy calls Blackjack who appears faster than Tempest, who Jason has only successfully called on three other times. With Piper riding with Jason, they head over to mile marker 32. When they are there they meet Bacchus who explains he planned on meeting Ceres. Throughout the encounter, Bacchus refers to Jason as "John Green." (As he does so with the campers back at Camp Half-Blood in his original Greek aspect, Dionysus) Suddenly Bacchus senses Gaea and flees.



Gaea has Eidolons enter Percy and Jason to fight. Gaea forces Piper to choose which boy she can save. Instead, Piper has Blackjack knock Percy out (after Percy has knocked out Jason) using her Charmspeak. They make it back to the ship where the boys are recuperating. Percy and Jason discuss whether or not they could have really killed each other until Annabeth breaks it up telling the boys, "I'm sure you both would be wonderful at killing each other" and that they need to hold a meeting. At the meeting, Piper tells the Eidolons who are still possessing Leo, Percy, and Jason to leave the ship. After the Eildolons are gone, Jason states that the Romans won't follow them past the Mediterranean Sea, as it is the place of no return and by crossing into it, they would all be listed as traitors of Rome.

Eventually, the seven make their way to Charleston and are under fire by the Romans who have caught up to them. Percy and Jason create a storm around the ship to push the Romans back and create a quick get away as the take off into the sky. They make it into the Pillars of Hercules and when they arrive they decide to send Jason and Piper to talk to him about passing through. Jason mentions that their quest was given to them by Hera, quickly angering the minor god, who sends them on the hard task of retrieving the horn of Achelous. The two demigods get the horn and go meet Hercules again, who gives them permission to pass as they had retrieved the horn. He then asks for the cornucopia, but Piper refuses to give it to him, as he doesn't deserve something as precious as the cornucopia. This angers Hercules and he prepares to kill them all, but Piper releases an unprecedented amount of food from the cornucopia, which completely buries the god, and Jason then flies them to the ship while Percy keeps Hercules at bay with massive waves and they start to take off.

After the ship has passed the Pillars, the ship is continually attacked. During this time Jason is defending the ship by throwing lightning and creating storms, which wears him out greatly. He switches taking watch with Percy whenever the ship goes into the water. Soon after the ship is attacked by Chrysaor, where Jason is quickly detained. Percy Jackson defeats him and they fly into Rome safely. Once they are in Rome, Jason and Piper stay on the ship while the others scout out and have a picnic. Jason reveals that his birthday is July 1, which is the day they arrived in Rome. Percy comes back from dropping Annabeth off at her quest. Piper reveals her vision of a spiral staircase. The boys then persuade Piper to find these staircases.

When they find the staircase, Percy goes down first in case there is water, as he can breath in water and won't drown. When he comes back, he tells them he found something weird, which turns out to be a Nymphaeum. Soon, the nymph Hagno and several others, the nine nymphs that watched over Zeus when he was born appear and flood the chamber with evil water. Percy is unable to breath and the nymphs begin to drain the three of their power, stealing Percy's control over water, Jason's control over the rain, and Piper's beauty in order to be young again. Piper comes up with the idea to funnel all their positive thoughts into the Cornucopia, which releases the positive emotions as clean water. As the three release almost all their power into the Cornucopia, the nymphs become young again and spare the three, as the power they gave them as a gift and they restore the trio back to full strength, as well as telling them the location of Otis and Ephialtes.

They quickly arrive at their lair and find the jar Nico di Angelo is in unguarded. When they approach it, a platform lowers with one of the twin giants on it, Ephialtes. Otis soon joins his brother and they begin to talk about their plan to release monsters into Rome to destroy it as their biggest show yet. They had also planned on letting Nico die in public, but because of his death trance, he has been asleep and has no entertainment value, leading to the giants tipping over the jar and releasing him. Nico rolls out and Percy couldn't tell if he was alive or not. Percy tries to keep them distracted as Nico wakes up and begins to crawl away. The twins mention that even if Percy should be kept alive for the bounty, Annabeth is already doomed and Leo, Hazel, and Frank are locked up, meaning the giants can kill Percy, Jason, and Piper (they even claim to have choreographed their deaths). They also mention that Gaea will rise in only a month.

The three lunge into battle, with Jason attacking Otis, Percy attacking Ephialtes, and Piper trying to defend Nico from the released animals and monsters. A hydra is even released, leading Percy to set a large stack of fireworks off, which destroy the hydra, but also destroys many different areas of the twin's hypogeum and knocking out Piper. When Jason runs to her, Otis tosses his spear at him, which Jason deflects with a gust of wind and it strikes Ephialtes right in his side, turning him to dust. A piece of the ceiling also falls on Otis, turning him to dust as well. However, the two need to be killed by a god and demigod working together and they instantly reform. As they taunt Percy and Jason, Bacchus appears on the scene and raises them into the Colosseum, which Bacchus filled with ghostly spectators. However, Bacchus refuses to help unless the two can 'entertain' him. Jason and Percy agree to fight together this time and charge the two. Jason blasts the two with wind, causing the fake mountain the two were holding onto to fall on Ephialtes. After insulting Swan Lake, Otis charges the two and Jason blows him into the lake and the two stab him with their swords, turning him to dust.

Percy then uses the water to keep the dust from reforming, but Otis' head is able to reform. Ephialtes then escapes from the fake mountain and charges the two, managing to disarm them both and almost kills them, but the Argo II appears overhead and blasts them with Greek Fire from the cannons. Bacchus considers this entertaining enough and stabs both giants with his thyrsus, defeating them. Before leaving, Bacchus informs them of the best place to reach Annabeth before she is killed and vanishes. Leo, Hazel, and Frank rejoin Percy, explaining that Frank turned into a weasel and dug to the surface, where they managed to call Coach Hedge to rescue them.

Back on the ship, Jason watches as Percy and Nico argue about the two camps. Nico explains that Hades had shown him Camp Jupiter because he knew that both camps would need to work together. Nico also goes on to say he knows where the Doors of Death are on both sides, one in a temple in Greece called the House Of Hades, but the entrance in the Underworld is in Tartarus. Everyone agrees to worry about this later and head off to save Annabeth.

The Argo II arrives at the cavern where Annabeth is and blasts a hole in the ceiling. Jason, Frank, and Hazel all work together to help lift the Athena Parthenos onto the ship just as the floor collapses. As they are securing the statue onto the ship, Percy, along with Annabeth and Arachne, fall through the hole in the ground that leads to Tartarus. Afterward, Jason feels guilty because he believes if he had flown down, he could have saved them. Nico tries to comfort him, by pointing out that even if Jason had flown down to get them, the only possible outcome would be all three of them falling down into Tartarus. They all decide to head for Greece to the Doors of Death and hope that Percy and Annabeth are doing the same from Tartarus.

Percy Jackson's Greek Heroes
Right after finishing his narration of this book, Percy reveals that after the events of The Blood of Olympus, he, Jason, and the rest of the Seven started the tradition of monthly Argo II reunion parties, and he is quite worried about being late to the current one.

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. Jason and Piper, while angry at Leo for his long absence, are extremely relieved to learn that he is alive, and both of them spend most of September searching for Leo, Festus, and Calypso.

Eventually, however, Chiron persuades them to resume their school year, and so Jason and Piper depart to a school in Los Angeles (where Tristan McLean lives), taking Gleeson Hedge, Mellie, and Chuck along with them.

The Hidden Oracle
Jason is not present at Camp Half-Blood when the de-powered Apollo and Meg McCaffrey arrive, so Nico di Angelo explains where he and the rest of the Seven are now while showing Leo's holographic message. It is noted that Jason is in Los Angeles, studying with Piper after an unsuccessful search for Leo.

The Dark Prophecy
Thaila tells Apollo to check in on her brother for her if he and Meg make it to Los Angeles.

The Ship of the Dead
Percy mentions Jason when he talks about how you don't have to know about the sea to fight in the sea. He explains how the son of Jupiter saved him from Kymopoleia by offering her fame to Magnus and his friend, Alex Fierro.

Personality
Jason is a very serious young man with a moderate sense of humor. He is sweet, kind, gentle, soft-spoken, honorable, and humble. Jason is someone who always follows the rules, but gets more laid-back as the series progress. He also has a strong sense of honor and justice as shown by his great compassion. He greatly cares for his friends and family willing to risk his life to protect or help them. Though a natural leader, Jason can be plagued by doubt and criticizes himself whenever he makes an error. There are notable similarities between Jason and Percy Jackson such as their strong senses of justice and fairness, their loyalty to their friends, and the fact that they're both natural leaders. When on board the Argo II, Jason comments that he has never been surrounded by equals before, as most of the time people look up to him because he is a child of Jupiter. Jason is also very accepting of others, since, unlike many others, he felt no contempt or prejudice towards Nico, even after finding out that he was gay. Jason even offered Nico his friendship and support and encourages him to take a risk and come out. Jason is often described as "too perfect" by his friends at times, doing everything the right way and always doing the honorable thing. But as the series progress, Jason starts to show a more relaxed version of himself at his time at Camp Half-Blood.

Jason is also very confident in his abilities. After he and Percy were possessed by the Eidolons and fought each other, Jason commented that he was worried that he could have killed Percy, instead of Percy possibly killing him. He also chooses to face Lityerses in combat instead of being turned to gold by Midas. Jason was even ready to face the Giant King Porphyrion, even though he knew he could not win.

Appearance
"Never seen Jason fly before. He looks like a blonde Superman."

- Percy Jackson about Jason Jason Grace was described as handsome and attractive: the regal features of a Roman statue, sky blue eyes, close-cropped blond hair that grew out during his time at Camp Half-Blood, and a small scar on the corner of his lip from trying to eat a stapler when he was two years old. Piper noted that his face was kind and gentle but always looked a little sad.

He once observed that he looks nothing like his father, which assumes that he looks more like his mother. He is very tall, being one inch taller than Percy Jackson, despite being nearly a year younger, with an athletic build, and having well-muscled and tanned arms and legs. His tattoo has the picture of an eagle with SPQR and twelve lines, indicating he has been at Camp Jupiter since he was three or four years old. Piper noted that his eyes seemed to hold some deep sadness, much like her father's. After his encounter with Sciron, Jason's hair has had a groove in it where the Celestial Bronze bullet grazed it and was noted to have gotten taller.

His looks attract female attention, such as the instances with Drew Tanaka, and the girls from Wilderness School. Also, when Aphrodite gave Jason's team a makeover, Jason was the least modified, implying that Aphrodite approves of his physical attributes.

In The Blood of Olympus, Jason started wearing glasses made out of Imperial Gold due to being diagnosed by Asclepius as nearsighted.

Abilities
General Abilities= Demigod Abilities= Being the son of Jupiter, he is an extremely powerful demigod, who not only has authority over creatures of the sky but can also influence the forces of weather and can control the air around him. During his time at Camp Jupiter, Jason was considered the most powerful demigod in the legion. Hazel believes that Jason is the most powerful demigod she knows, however, the abilities of Nico and Percy seemed to have made her question her judgement, as she believes only Nico's power rivaled (and possibly even surpassed) Jason's. However The Blood of Olympus, Dylan states that Jason has now become significantly more powerful than he was during their first meeting in The Lost Hero.
 * ADHD: Like most demigods, he possesses inborn supernatural battle reflexes and senses that he uses to analyze the fighting style of his opponent.
 * Combat Prowess: He is trained in Roman legionary warfare.
 * Dyslexia: His brain is hardwired for Latin.
 * Fighting skills: He is an exceptional spearman and swordsman. Jason's fighting skills are amazing seeing as how he bested Kronos' brother, Krios in hand to hand combat, a feat only Hercules has accomplished, who is technically Jason's older brother. He also slew the Trojan Sea Monster, easily defeated the skilled swordsman Lityerses, and dominated Mount Othrys by fighting through hordes of Scythian Dracanae and toppling Kronos' black throne. He had easily killed the storm spirits in The Lost Hero, and was holding his own against one of Medea's golden dragons. He has also shown to be able to hold his own against larger, more experienced, and more powerful opponents such as the Giant Enceladus, held a slight advantage against Polybotes even underwater, and even defeated Titans such as Krios. When possessed by Eidolons in The Mark of Athena, Jason fought Percy Jackson on even footing (Piper couldn't believe the speed of their sword fighting), and was only knocked out because he was distracted by Piper's Charmspeak. Jason can even use improvised weapons to fight as he used a wooden plank in the Wolf House in The Lost Hero to fend off numerous opponents. In The Blood of Olympus, Jason is able to fight two hundred ghosts of the Suitors, along with the help of Annabeth and Piper (replicating the feat of Odysseus), and ultimately defeats the Giant King Porphyrion with Zeus's help. Jason has even shown to be equal to Percy when it comes with fighting, even though Percy later states in The Son of Sobek that not many people can fight him well, indicating that Jason is a better fighter than most. Because Jason is trained in Roman legionary warfare, his fighting style includes analyzing your opponents' moves and learning their style, which was proven effective against Lityerses.
 * Superhuman Strength : Being a demigod of Jupiter, Jason is considerably stronger than the average mortal, and is stronger than most demigods. As he was shown to knock out demigods with one blow, smack around full-grown wolves with just a wooden plank, topple Kronos's black throne, deflect blows from giants, and was able to shatter Clytius's metal armor to pieces with one kick, even if the armor was a little weakened it was still an impressive feat. He threw Coach Hedge's club at Dylan, even when it was extremely windy. Most impressively, he claims to have destroyed Krios with his "own hands."
 * Superhuman Agility : Being a demigod, Jason is agiler than a regular mortal. As he was shown to vault over tall objects with ease, climbed all the way up to a huge Porphyrion head before the giant even reacted, and countless other feats.
 * Superhuman Durability : Being a demigod, Jason is more durable than a mortal, as he was able to shake off a kick in the chest from a giant, shook off getting hit by chariot in mid-air, and only manage minor injuries when getting hit by an explosion caused of the breaking of his spear. Jason fell from the sky into the Cyclopes home The Lost Hero, but had shown no signs of discomfort. He even managed to shake off several hits from the god, Eros.
 * Superhuman Reflexes : Being a demigod, Jason is faster than a regular human. He was able to dodge Enceladus attacks even when the earth was pulling him down in the Lost Hero. He easily dodged a spear thrown from Otis, the giant, and dodged Lityerses attacks, despite the latter being a fast fighter. He even deflects an arrow shot from Eros, even when he couldn't see the arrow.
 * Intimidation: Each Roman Demigod trained at the Wolf House has mastered the wolf-stare, a skill that intimidates their enemies so it is assumed Jason has learned it.
 * Medical Skills: Jason has shown that he has some medical experience, as he was able to fix Piper's hurt foot with just a piece of wood, gauze, and duct tape.
 * Aerokinesis: As a son of Jupiter, he can control and manipulate the air.
 * Air Blasts: He can control, and generate very powerful winds and air currents, enough to instantly knock the Giant Otis down in The Mark of Athena, and a stronger one that sends Porphyrion himself flying in The Blood of Olympus.
 * Flying: He can ride air currents, making him fly. He can fly for hours without tiring.
 * Air Solidification: Jason has shown to be able to shape the air in different forms and shapes, from ropes to containers. The strength of these air containers was shown when he kept the primordial goddess, Gaea, from returning to earth.
 * Seeing Air Magic: He could see a path in the air, leading him to Boreas's palace in The Lost Hero.
 * Venti Control: He is able to dominate the will of more chaotic Venti.
 * Ropes of Wind: He can generate ropes of wind, "more tightly wound than any tornado" which he used to bind Notus' fiery Venti in The House of Hades.
 * Atmokinesis: As a son of Jupiter, he can control the weather.
 * Storm Generation: He can generate fierce storms, as seen in The Mark of Athena. His skill with this ability grows to such that in The Blood of Olympus he managed to summon a storm powerful enough to wound Gaea with an unrelenting bombardment of lightning (albeit, Gaea was separated from her domain at the time).
 * Storm Venti Control: As shown in The Blood of Olympus, Jason can summon storm Venti for a variety of purposes. He easily dominated Dylan and utilized him as a tornado. Later, he summoned "a legion" of Venti to amplify the storm he used to bombard Gaea.
 * Electrokinesis: As a son of Jupiter, he can control lightning and electricity.
 * Electrical Immunity: He is completely immune to electricity, having survived being struck by an electrical bolt "strong enough to kill twenty people" in The Lost Hero.
 * Static Electricity: Like his sister, he can generate huge bolts and arcs of static electricity.
 * Static Shocks: He can send strong electrical shocks through others on contact. One of his static shocks was powerful enough to send Khione herself sliding across the floor, even though unintentionally.
 * Lightning Bolts: He can summon extremely powerful lightning bolts from the sky, which Piper compared to an artillery shell in The Lost Hero. His lightning bolt was strong enough to destroy King Midas's mansion, which was made out of gold. He would go on to summon lightning powerful enough to stagger the giant king, Porphyrion and blacken his face. As the series progressed, his lightning bolts became more powerful. And whilst the effort it took him to summon them is mentioned to make him feel faint in The Lost Hero, the effort required dramatically reduces by The Blood of Olympus. Once, his lightning knocked Percy off his horse. Jason had summoned enough lightning to melt iron nearly instantly in House of Hades. In The Blood of Olympus, he managed to summon a lightning bolt powerful enough to destroy a host of basilisks, despite being underwater. In the final battle against the Giants, he used a lightning bolt to augment himself when he leapt at Porphyrion, knocking the Giant King to his knees.
 * Limiting Electrical Conductivity: In The Blood of Olympus, Jason was able to fry Polybotes' basilisks with electrical tendrils underwater, without electrocuting Percy in the process.

Magical Items

 * Ivlivs: A coin made of Imperial Gold. It turns into a golden sword on heads and a golden javelin on tails when flipped. The weapon hasn't been named yet in the series, but the coin has the word 'Ivlivs' on it, which is Latin for 'Julius.' It was destroyed by Enceladus during his and Jason's fight on Mount Diablo.
 * Gladius: Juno, the Roman form of Hera and Jason's patron, gives this to him at the end, so that he has a proper weapon. It is a Roman Gladius made of Imperial Gold.

Magical Pets/Companions

 * Tempest

Family
Thalia Grace = Jason's sister, Thalia Grace, was born to Zeus. Thalia is a Greek demigod, because when Zeus visited her mother the first time, he was in his Greek form. When Zeus came to Jason's mother for the second time, he came in his Roman form, Jupiter. Jason is therefore a Roman demigod, while his sister is Greek. It is shown that Jason cares for his sister. He feels somewhat depressed that Thalia has found a new family in the Hunters of Artemis. However, it is shown that when Jason first saw her picture, and Annabeth told him her last name, his instincts told him she is dangerous, as Juno left enough memory to know that digging up his past could be disastrous and that she was his sister. Jupiter/Zeus = Jupiter sired Jason, his second child with Ms. Grace. Like all the Roman gods, Jupiter rarely involves himself in the life of his child. As a Roman, Jason was raised to hold a deep respect and reverence for Jupiter as the king of the Roman gods and chief god of Rome. At the end of The Lost Hero Jason transfers this respect to Zeus, he talks to the statue of Zeus in Zeus' Cabin on how hard Zeus must have it as the leader and has to set an example.

Throughout the books, Jason's view of his father changes. Early on, he insists he is a son of Jupiter and not Zeus, but by the end of the last book, he sees both as equally his father. As he becomes more Greek, he comes to accept that Jupiter is far less than the perfect god he was raised to believe. In The Blood of Olympus, he goes so far to risk Zeus' wrath by openly questioning him in front of the other gods when Zeus wrongfully blames Hera and Apollo for the Second Giant War. In the end, while he still respects his father, it is far less than it once was. Beryl Grace = Since Jason has forgotten most of his memories, we can imply that he wasn't taken care of by his mother, since Thalia said that she was the one who took care of him until Beryl Grace, his mother, gave Jason away to Juno.

Love Interests
Piper McLean = She and Jason share many romantic moments throughout The Lost Hero. He has a great deal of concern for her, as he does everything to help her. He puts his hand on her waist to support her when she collapsed due to hypothermia. At the end of The Lost Hero,, the two have a romantic moment at the end of which they repeat what had apparently occurred in Piper's Mist induced the memory of them kissing. Also, Jason has strong feelings for Piper, but he is worried about their future.

In The Demigod Diaries, Leo comments that Jason and Piper are dating, which takes place two months after their quest to save Hera. Piper also gives Jason a goodbye kiss just in case they don't get to see each other if the engine of the Argo II blows up. Since the engine did not blow up they continue to date for the next 6 months.

In The Mark of Athena, Annabeth introduces the two as boyfriend and girlfriend. She also gives him the nickname Lightning Boy. Piper constantly doubts that Jason does not have any feelings for Reyna, despite the many times he denies it. Even so, their relationship remains intact. When the two are drowning (along with Percy), Piper mouths to Jason that she loves him.

In The Blood of Olympus, Jason admits that while dating the daughter of the goddess of love, he is always afraid of doing something unromantic and angering her mother. After the defeat of Gaea and the Giants, Jason kisses her passionately under the stars. He reminds her of their first kiss, which was really just a trick of the Mist, but has now finally come true. He tells her that they're starting over, and that was their first kiss. They then rest there, and Piper says that, for once, she feels like it is it possible to start over. Reyna Avila Ramírez-Arellano = The memory of her makes him rethink what he is doing with Piper, and makes him uneasy, though he does not know why. It's revealed in The Son of Neptune by Reyna to Percy that if Jason hadn't gone missing, a romantic relationship might have developed, since Reyna said that it was common for there to be romance between praetors, since they work together so much. When the Argo II arrives in the sky Reyna says that she hopes Percy is right and Jason is aboard the ship, stating that she has missed him.

In The Mark of Athena, it is stated by Jason, that he'd never felt more than friendship for Reyna. However, when the two once both went on a quest, after Reyna talked with Aphrodite, he states that she never acted the same to him again. Piper speculates that Reyna admired Jason mainly for his noble behavior and his good self-discipline.

Friends
Leo Valdez =

Despite their time at the Wilderness School being fake, Leo still considers himself Jason's friend. He even volunteers to go on a quest with him and goes to repair the Bronze Dragon to give them a way of transportation. Despite Leo and Jason being good friends, Leo feels jealous of Jason. People look at Jason and respect him for being the son of Zeus (really Jupiter) and think he is handsome and powerful, while he only sees himself as the lowly mechanic. He also feels left out as Jason and Piper start to form a real relationship. The only time he doesn't feel jealous of Jason is when Thalia talks to Jason about his past and how Hera had taken him away from their mother. Leo remembers that while his own life wasn't that good, his mother wasn't possessive of Hephaestus and only wanted Leo to know him.

Jason, on the other hand, harbors a great deal of respect for Leo, and is inwardly ecstatic when Leo offers to accompany him on the quest to save Hera. He acknowledges his ability to keep him and Piper alive in The Lost Hero, noting that their quest would have failed if not for him. Jason feels more at ease when around Leo, as he requests that he stay with him during his talk with Thalia for support. Even after Leo fires on Camp Jupiter due to the influence of the Eidolons, Jason (along with Piper) does not blame Leo, confident that he would never actually do such a thing despite the other demigods' doubts.

Leo remains Jason's best friend throughout the series, and is devastated after Leo's death in The Blood of Olympus. Several days later, he and Piper do their best to remember all of the cheerful memories associated with Leo and stay up all night on the roof of Cabin 1 in the process. Part of him is still hopeful that Leo has somehow survived, despite all odds.

In The Hidden Oracle it is revealed that after Jason and Piper listen to the holographic scroll and learn of Leo's survival (several days after Gaea's), they are exuberant, and tirelessly search for him for most of September, until Chiron finally persuades them to resume their school year. Percy Jackson = Jason and Percy first meet in The Mark of Athena and have been shown to be on good terms. Percy says that Jason "thinks the same way he does" and mentioned a "spark of friendship." They both share many similarities: both are sons of one of the Big Three and extremely powerful demigods; both are excellent swordsmen; both are leaders at their respective camps; both have killed the Giant Polybotes; both hate Octavian; and both were chosen by Juno to be switched in order to bring the Seven Heroes of Olympus together.

Annabeth calls their relationship a "budding bromance", as the two seem to get along well. While fighting Otis and Ephialtes, the two are able to work well together as a team and manage to earn Bacchus' respect. It is also shown that when working together their powers get more intense when they created a huge storm at Fort Sumter while fighting the Romans.

Jason and Percy also have a small rivalry going, such as when Jason and Percy both go for the head chair at a table and Jason even causes sparks to fly, but Annabeth took the chair in the end. Also, when apologizing to Percy after being possessed and force to fight each other, he comments that he could have killed Percy. Percy turns this around saying he could have done the same, but Jason doubts this unless there was an ocean in Kansas.

When Percy and Annabeth come out of Tartarus in The House of Hades, Jason is the first person to hug Percy in greeting. In The Blood of Olympus, Jason and Percy continue to be brotherly (even referring to each other as "bros"), and Jason admits to admiring the son of Poseidon for once being able to turn down Zeus' offer of immortality. Hazel Levesque = Jason remembers her in the last part of The Lost Hero as being her friend back at the Roman Camp. In The Son of Neptune, Hazel tells Percy that after she arrived, she had only known him for about a month before he disappeared, so they hadn't known each other well. From Hazel's point of view, it is assumed that she and Jason were friends. She even compares Jason to Percy, stating that they both had the same look, as if they had both seen their fate, and were waiting for it to happen. When they both confront Sciron, in The House of Hades Hazel notes that she couldn't figure Jason out well, as he acted "too perfect", and that she would rather have Nico, Frank or Percy at her back. Still, Hazel does trust Jason, and they cooperated well in defeating Sciron. Frank Zhang = Jason and Frank first meet in The Mark of Athena, despite both coming from the Roman camp, similar to Percy and Leo. The two don't have much interaction in the book, but according to Hazel, Frank is "in awe" of the son of Jupiter. In The House of Hades, to save everyone, Jason signs over his praetorship to Frank, as the Roman zombies don't recognize Jason anymore, due to him signing himself over to the Greeks of Camp Half-Blood. After saving Percy and Annabeth, the two are seen talking quietly at the helm. In The Blood of Olympus, Jason and Frank also lead the backup charge into the Parthenon after Piper, Percy, and Annabeth. Annabeth Chase = Though it seemed like it to Piper, Jason likes Annabeth as a friend but has no romantic feelings towards her. In The Lost Hero, Annabeth was the one who told him about Thalia, which sparked the memory of her and his last name, Grace. Annabeth claimed Thalia had never told her she had a little brother, but Jason insists that she does. At the end of the book during the Senior Counselors' meeting, when Jason tells where he's from and where Percy is, Annabeth says that she is going with them, mostly because of Percy. Jason agreed that he would want her along, mostly because he knew that she had already figured out where Percy was and the danger he could be in. In the beginning of The Mark of Athena, it is shown that Annabeth still somewhat distrusts Jason, thinking that he is too perfect because he always does everything nobly, does nothing against the rules, and even looks too perfect and she half expects him to turn on them at the second they land. However, during their journey to Rome they come to rely and trust each other more, and after Percy and Annabeth fall into Tartarus, Jason feels responsible for not saving them. Nico di Angelo = In The Mark of Athena, when Nico's sister, Hazel was intent on saving him from Rome, Jason pointed out that it might be a trap and also found Nico's loyalties doubtful, because despite knowing about both the camps, Nico did not tell anyone (a statement which made Hazel incredibly angry). Jason had also learned from Percy about the incident in Hades' Palace (in The Last Olympian), thus becoming uneasy about being around Nico, and even admits to being afraid of the son of Hades. This, however, changes in The House of Hades, when they venture into Salona to retrieve Diocletian's Sceptre and encounter Cupid.

There, Cupid forcibly makes Nico reveal about his true feelings for Percy, nearly reducing him to tears. Jason finally understands why Nico always shied away from people and was always alone and for Nico's sake, keeps it a secret. After the encounter, Jason becomes much more empathetic towards Nico. At Notus' palace, Jason tries to befriend Nico as he feels it was the only way to help him out, but Nico once again pushes him away. Jason angrily retorts that Nico had run away from everyone for far too long and that he should come out of his shadows and trust Jason. Later, as they approach the House of Hades, Nico first offers the chalice full of poison to Jason, asking him to trust him. Nico fights along with the other demigods in the ensuing battle and it is implied that he and Jason are now on good terms.

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 Gaea's defeat, when 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. Bobby (demigod) = Jason starts to remember him at the end of The Lost Hero. When Juno returns some of Jason's memories, he remembers several of his friends, with Bobby being one of the names mentioned. Not much is known about him but his name. Bobby is only seen in The Son of Neptune, when he gives Percy, Frank, and Hazel a ride on Hannibal to the Camp Jupiter gates.h Gwendolyn = Because Jason kind of remembers her, it can be assumed they had been friends. In The Son of Neptune, she was a Centurion of the Fifth Cohort, but after the position was given to Frank, she retired after ten years of service to attend college in New Rome. Dakota = A Senior Centurion of the Fifth Cohort, he and Jason were friends at Camp Jupiter. Jason apologizes to him before knocking him unconscious at Fort Sumter.

Trivia

 * Jason was named after the original Jason, Hera's favorite hero, by Jupiter to please Juno after being conceived.
 * Percy Jackson, Annabeth Chase and Jason Grace are the only three demigods out of the Seven to fight in the Titan and Giant Wars, consecutively (though Nico di Angelo has participated in some battles of both).
 * Of all the Greek and Roman children of the Big Three, Jason is the only one who is not confirmed to have visited the Underworld.
 * Jason has fought six Giants and killed them, albeit with some help.
 * He killed Enceladus with the help of Piper, Leo and a lightning bolt from Zeus.
 * He killed Otis and Ephialtes with the help of Percy Jackson, Bacchus, and Leo.
 * He killed Clytius along with Nico, Piper, Hazel, Frank and Hecate.
 * He helped Kymopoleia kill Polybotes.
 * He fought alongside Zeus to kill Porphyrion.
 * Similar to the original Jason, he was aided by Juno and was recognized by the fact that he was wearing only one shoe.
 * Jason and Thalia are the only known siblings to be from different aspects of the same god. Thalia is a Greek demigod (being a daughter of Zeus), and Jason is Roman (being a son of Jupiter), as stated by Hera/Juno herself.
 * Unlike other children of Zeus/Jupiter, Hera doesn't hate him or try to kill him like his other siblings. Hera said that she is Jason's patron and Jason is her champion.
 * Thalia and Jason are both mentioned to like cheeseburgers, just like Percy does.
 * The scar in Jason's mouth came from trying to eat a stapler when he was 2 years old. Because of this, Coach Hedge says he has 'excellent taste'.
 * It is mentioned by Aeolus that Jason once stayed with him on a quest to kill a sea monster. It is later revealed Jason had killed the Trojan Sea Monster.
 * Although one of the demigod "afflictions" is usually dyslexia, Jason could read Midas' brochure for Gold: Invest for Eternity just fine. Although it may have been in Latin or Jason may not have dyslexia, like Frank Zhang.
 * Jason claims to be the Praetor of the First Legion in The Lost Hero, but Camp Jupiter is made up of only the Twelfth Legion.
 * It is revealed in The House of Hades that he wanted the Twelfth Legion to be renamed the First Legion.
 * Jason sometimes feels uncomfortable with the attention that is given to him due to him being the son of Jupiter and people expecting that he will not fail.
 * Piper calls Jason Sparky on occasions.
 * So far, Jason is the first known mortal to have seen a god's true form and lived.
 * Though this could've been because the Doors of Death were open at that time, giving Piper the chance to call Jason's soul back using charmspeak.
 * Despite being Roman, Jason is a Greek name, meaning "healer". This is because Jupiter felt naming him after Juno's favorite hero would quell her anger.
 * Jason's name being a way to placate Hera may be a nod towards his older half-brother Hercules, who was named after her. Although it is to be noted that Hera did kill Hercules and his family.
 * Jason's birthday is revealed to be July 1, the first day of the month named after Julius Caesar and was also considered Juno's sacred day.
 * Jason and Piper are the only couple who aren't from the same camp (Jason's Roman, while Piper's Greek).
 * In every book appearance he has appeared in except The House of Hades and The Blood of OlympusJason has been controlled by another force and made to attack an ally:
 * Medea used Charmspeak on Jason and Leo in The Lost Hero
 * Jason was possessed by an eidolon and attacked Percy Jackson in The Mark of Athena
 * Jason's birthday is the first day of July. In November, the Greek form of his father, Zeus, closed all communications to and from Olympus. If every first letter of the months from July to November is taken, it spells Jason (July, August, September, October, November).
 * Like Percy, Jason is also named after a legendary Greek hero.
 * Jason had wanted to rename the Legion the "First Legion", which symbolized a new start for Rome, but the idea was shot down.
 * Jason's favorite treat from the New Rome bakeries is brownies.
 * He is the only member of the Seven not to have met his godly parent in his respective form.
 * He is the only one to have a sister with the same mortal parent, but different god aspect.
 * When Jason, Percy, and Piper met Bacchus at the Topeka sign, Bacchus called Jason "John Green," which is the name of an author who also writes young adult novels.
 * Apparently Jason is nearsighted, causing him to wear glasses in The Blood of Olympus. This makes him one of the only demigods to wear glasses, along with Meg McCaffery, as shown in The Hidden Oracle.
 * He has a mole on his left foot.
 * Interestingly, Jason and Percy are the only two demigods that are compared to superheroes from DC Comics–Percy claims that Jason looks like a blonde Superman when he flies, while Leo and Meg jokingly call Percy Aquaman for his water-based abilities. Percy's half-sister Kymopoleia, on the other hand, is compared to a superhero from Marvel Comics – Captain America.
 * Jason has a chapter title in honor of him in The Sword of Summer.
 * Chapter 48 is "Hearthstone Passes Out Even More than Jason Grace (Though I Have No Idea Who That Is)"
 * The chapter makes fun of Jason constantly getting knocked out as seen in The Mark of Athena.

Jason Grace