|“||I am the saviour of Rome. I was promised!||”|
Reyna Avila Ramírez-Arellano tells Hazel Levesque that after she questions Percy Jackson, she will send him to Octavian who will consult the Auguries and decide what to do with him after conferring. Percy describes Octavian as a "teddy bear murderer", as he saw many shredded teddy bears, and as Octavian tore apart his "Pillow Pet"
The first time Octavian meets Percy is at the Temple of Jupiter Optimus Maximus. Percy quickly learns that he is blackmailing Hazel into voting for him in the upcoming election for the Praetor, as he either found out about her raising Alcyoneus and being brought back from death.
Later during the war games, he is suspected of killing Gwen by spearing her from behind possibly after the games were already over. Frank Zhang notes that Octavian was the only one without a pilum and was at Gwen's back when she was stabbed. Gwen returns from the dead, claiming that she saw a man who was asking for a coin, but she just left. Frank pulls the pilium out and the wound heals automatically.
Mars appears on the field a moment later to issue a quest, saying that his son, Frank, will lead it. He also orders Percy to go for the quest to learn to have some respect for Mars. Octavian claims that they need a prophecy and states that he will go fetch his stuffed animals for one. Mars simply writes down a prophecy. The prophecy is extremely blunt and Octavian protests, declaring that prophecies must be wrapped in riddles. When Mars pulls a grenade from his belt, Octavian quickly changes his tone and treats the order as an actual prophecy.
The second time he is seen is during the Senate meeting where he convinces the others into trying not to give Percy, Frank, and Hazel supplies on their trip, as that is the traditional Roman way. However, Reyna allows them to use the The Pax for their quest.
After the battle against the Giant Army, Percy is raised on a shield as the Roman campers chant "Praetor", electing Percy to the position, much to the irritation and unhappiness of Octavian. At the Feast of Fortuna, he gives Percy his tattoo, but whispers to Percy that he hoped it hurt. He later claims that Camp Jupiter will have good luck.
At the senate meeting the following day, Percy informs all of Rome about the existence of Camp Half-Blood and that he is, in fact, a Greek. He also informs Rome of the imminent arrival of the Argo II, whose passengers were coming to help fight against Gaea. Octavian was one of Percy's fiercest opponents at the meeting, claiming that Greeks were Rome's enemies, and shouldn't be trusted. He demands that the Romans take military action against the Greeks, saying that they should destroy them before they have a chance to land. When Percy says that the Greeks are peaceful and that Jason Grace is on board, Octavian accuses him of lying and once the ship comes into view, he begins to scream "Beware Greeks bearing gifts!" He points at Percy, accusing him of leading the Greeks to the camp. However, Reyna says that they will allow them to land, but the Legion forces would stand by and be ready if it was a trick. Octavian opens a stuffed animal and says these omens are horrible and death is coming. After they agree to give the "Greeks" peace, Octavian walks out of the senate in disgust.
Octavian coldly greets the Greeks and Jason when they come off the Argo II. While talking about the quest, Ella says the entire prophecy, causing Octavian to become suspicious for what she said. Later, when Percy offers to give back Jason his praetorship, calling it "no biggie," Octavian becomes outraged saying, "The praetorship of Rome is 'no biggie?'"
When Leo Valdez is possessed by an Eidolon, he unwillingly attacks New Rome and Octavian is one of the first to retaliate and start war between them and the seven, convincing the Romans that Greeks are enemies and they must pay for what they have done. The seven rush back to the Argo II, and quickly leave, causing the Romans to pursue them.
In Charleston, the Romans find the seven thanks to Octavian and his auguries. Percy douses Octavian in water to stall him. He is later seen through Katoptris with Reyna, looking at an invasion map in New York.
Octavian accompanies Reyna during her meeting with Rachel Elizabeth Dare and Grover Underwood. When Octavian spots Rachel and Grover he immediately says to check for weapons and that they better be meeting them for surrendering terms. When Reyna hands him the letter that was sent from Annabeth Chase in Tartarus, Octavian is convinced that it is a "Greek trick". He tells Reyna that she is crazy for believing what the Greek said are true. He then continues to doubt that Rachel is the Oracle of Delphi. Rachel tells the Romans that Ella, the harpy, has read the Sibylline Books. Afterword, Octavian yells about how the Greeks always lie and that they "stole" the harpy. Reyna states that she will go to Greece to retrieve the Athena Parthenos. Octavian tells her that it's insanity and that the augur is in charge while she is gone. Once Reyna leaves, he tells the rest of the Roman officers that the legion is changing their plans.
Octavian is seen in a dream inviting Bryce Lawrence back into the legion as a Probatio in the Fifth Cohort, he has appointed himself to Pontifex Maximus. He is then seen at the Roman base camp recruiting monsters and exiled legionnaires to attack Camp Half-Blood, preparing many onagers (obtained from the financial support of god-emperor Nero and the Triumvirate Holdings). Later, Octavian goes up to Nico di Angelo, Will Solace, Cecil, and Lou Ellen when they were seen. He tried to start the invasion but was stopped by the Greek forces. Reyna then returned the Athena Parthenos moments before Gaea awakes at the camp. He attempts to fire an onager at Gaea but, unknown to him, his cape was caught in it. He is then confronted by Will Solace and Nico di Angelo who try to convince him not to fire. He says Apollo spoke to him, telling him that he would save Camp Jupiter. Michael Kahale then comes to him and guards Octavian. The Augur then fires, setting him on fire, flying towards Gaea and Leo Valdez, shrieking in horror and dying on impact. According to Leo, he heard a comet screaming like a little girl flying towards him, to his surprise and confusion.
Despite the madness of his actions, Octavian was hailed as a hero, as his attack may have helped permanently defeat Gaea. However, the Seven are left wondering if it just killed Leo instead (with Nico feeling particularly guilty, as he didn't prevent Octavian's death), which it did. Though fortunately for Leo, Festus managed to resurrect Leo by injected him with the Physician's Cure shortly thereafter.
Apollo mentions him when he was first cast down from Olympus as a human, the god blames Octavian for this. Rachel Elizabeth Dare discovered that the Triumvirate Holdings were the ones who supplied Octavian with those siege weapons, Apollo recalls that he dealt with the last triumvirate that included his son, the original Octavian. After the death of Caesar Augustus, whom Apollo was proud of, his descendants became increasingly arrogant and unstable.
Octavian was a stoically arrogant, condescending Machiavellian individual of unprecedented ruthlessness and self-righteousness. He was extremely ambitious and power-hungry, willing to use any heinous means, from extortion to manipulation, in order to achieve his goals. Unfortunately for any who might've crossed words with him, Octavian was highly intelligent, callous, cunning, manipulative and charismatic, the perfect orator.
He is portrayed as a potential threat if one became enemies with him, as Percy said, though the latter didn't seem to care. However, Octavian seemed to want to protect the camp and advocates a conservative approach when it comes to its affairs. He considered the Greek demigods to be enemies due to the ancient rivalry between Greece and Rome, and therefore, was very hostile towards Percy and the ideas he brought of truce with the Greek demigods aboard the Argo II.
Most of the time he was able to insult others discretely, which was how he was occasionally able to win favor in the council, even over Reyna herself. Octavian was also shown to be sadistic, as he did his best to painfully burn Percy when giving him his SPQR tattoo. Hence, Octavian seemed to value sadism and cruelty in others too, since he was quick to ally himself with the infamously brutal Bryce Lawrence, and also wanted Nico di Angelo as an ally, since he claimed to see a decent amount of ruthlessness in the son of Hades, which Octavian greatly appreciated.
In The Blood of Olympus, Octavian is shown as narrow-minded, arrogant, and downright foolish, as even the gods (mainly Apollo) condemn him and his actions. He disobeys Reyna's orders and recruits disloyal mercenaries and demigods of doubtful characters. Even when the Greeks try to reason with him, Octavian refuses to listen. His rash actions ultimately lead him to his horrific death.
Octavian also displayed traits of a religious zealot, often ignoring evidence that contradicted his own preconceived notions and ideals. His religious zealotry was principal in his xenophobic bigotry towards the Greek demigods, and he often used this shared hostility to rile the legion into following his command. As Octavian began to consolidate even more power his personality took a turn towards being completely megalomaniacal, with him promoting himself to the position of Pontifex Maximus. Following this self-appointed promotion, his tirades became much more rabid and deranged, his calm facade as a cultured and dignified politician giving way to that of a power-crazed megalomaniac whose calm and calculated speech and facial expressions gave way to a frantic, blood-thirsty, and bestial appearance.
Octavian was a skinny 18-year-old youth with blond hair, crazed blue eyes, and skin as pale as Nico's. Octavian's usual attire consisted of a white toga over a blue shirt and jeans. It is also mentioned that Octavian reminded Percy of someone, which means he could most likely be referring to Luke Castellan. He often held a ceremonial knife and stuffed animal on hand. His tattoo was composed of a lyre, the symbol of his ancestor Apollo, with SPQR inscribed above seven lines which represented seven years meaning that he had been attending Camp Jupiter since he was 11.
When he appointed himself Pontifex Maximus in The Blood of Olympus, Octavian donned Imperial Gold armor and jewelry, along with flowing purple robes. According to Nico, Octavian looks like a watered-down, unhealthy version of Will Solace – like a photo that had been copied too many times, without anything in him that makes a child of Apollo special.
- ADHD: Like all demigods and legacies, Octavian possesses inborn supernatural battle reflexes and senses that he uses to analyze the fighting style of his opponent.
- Oratory Skills: Octavian is a very skilled orator (something even Percy himself acknowledges in The Son of Neptune), effectively using words to achieve his goals. Most of the time he is able to insult others discretely, which is how Octavian is occasionally able to win favor in the council, even over Reyna herself at times. One of the very few characters to surpass Octavian in oratory skills is Nero.
- Fighting Skills: As the Centurion of the First Cohort, Octavian has some combat skill, but he was effortlessly defeated by Percy during the war games in The Son of Neptune.
- Prophecy: Being a legacy of Apollo, Octavian can interpret the will of the gods by reading the interior of stuffed animals, which are the modern day version of animal intestines. However, this ability isn't perfect and the messages will sometimes vary between two or more messages. Due to the gods' Greek and Roman forms fighting within themselves, his power over prophecy was lost, as with all children and legacies of Apollo.
Hazel openly dislikes Octavian due to his manipulative nature. Octavian tries to get her to vote for him so he could become the new Praetor by dropping a few hints that he knows about her past and that she was dead once, claiming that it would be horrible if the rumors about her turned out to be true.
Octavian dislikes Percy, and the feeling is mutual. He doesn't trust Percy because he is a child of the Greek gods, as opposed to the Romans, thinking that the Greeks are working with the forces of Gaea. He is also upset when Percy is elected praetor over himself. When they first meet, he slices open Percy’s panda pillow pet to Percy's dismay, because he had grown fond of it. Percy also quickly understands how powerful and domineering Octavian can be with words. Octavian shows his hatred of Percy after the latter tells everyone not to attack the Greek demigods when they land, but he still tries to rally them to attack. Percy utterly detests Octavian for his power hungry ambitions and schemes against Greeks. Percy enjoys using his superior rank of Praetor to silence him on at least one occasion.
While the two never seem to spend much time together, it is clear that Octavian believes Reyna is not a good leader. He often complains about Reyna not allowing a quest to find a book of prophecies (the Sibylline Books) that he is obsessed with. He also feels that she has let a power vacuum form during Jason's absence. He manages to make any unfavorable decision (such as making Frank a centurion) seem like it was all Reyna's idea and he is only following orders. Whenever Reyna makes a decision he approves of, he tries to make it seem like it was all his idea.
In The House of Hades, Octavian scoffs at Reyna's quest to Greece and directly disobeys her orders to not attack Camp Half-Blood. In The Blood of Olympus, he no longer recognizes Reyna as Praetor, just because she broke the law of entering the Mediterranean region.
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.
Despite having no known direct interactions with his divine ancestor, Octavian ruthlessly used his ancestor's influence to gain favor and power among the Twelfth Legion, using his skills at divining the future to his political advantage. However, despite claiming to have the favor of the Olympian gods, Apollo is distressed and disgusted with Octavian, referring to him in the objective term, "that thing," which indicates his complete depersonalization from Octavian, in effect, disowning him and clouding his gift of divining the future in retribution for his actions.
- Octavian is the only antagonist in The Heroes of Olympus series that opposes Gaea and the Giants.
- In The Blood of Olympus Octavian dies by launching himself with an onager (which is similar to a catapult), which is a bit of dramatic irony, as in The House of Hades, Frank said that their first order of business should be launching Octavian away in a catapult.
- Octavian is one of the names of Caesar Augustus, the first Roman emperor and a member of the second Triumvirate. According to him, everyone says he bears a remarkable resemblance to Augustus.
- His name could also be derived from Octabus, Latin for eighth.
- Octavian hoped to make Nico di Angelo, son of the Greek god Hades his ally, which is very ironic, considering his hatred towards Greek demigods and the fact that Pluto isn't a popular Roman god.
- The Ancient Romans used the entrails from sacrificed animals to determine the advisability of any chosen endeavor and event just as Octavian does with stuffed animals. As a ritual before meeting the oracle, the ancient Greeks did as well.
- Octavian is obsessed with the Sibylline Books.
- Although it is never stated how many generations Octavian is from Apollo, his family has been at Camp Jupiter for over a century, so he is at least fourth-generation.
- Despite earlier texts naming Octavian as a legacy of Apollo, Rachel Dare calls him a son of Apollo.
- Despite Octavian being a legacy of Apollo, he has an uncanny resemblance to Luke Castellan, son of Hermes.
- In spite of being a legacy of Apollo, Octavian seems to favor violence and is quite bloodthirsty, a common trait of Ares/Mars' demigod children.
- Despite the fact Octavian is referred to as an Augur, Augury is the ancient practice of divination through watching birds and the heavens. A diviner who foretells the future through the entrails of animals is properly referred to as a haruspex.
- The ancient Roman figure Octavian supposedly broke off Alexander the Great's nose from his mummy and stole his signet ring.
- Octavian bears an slight resemblance to Luke Castellan as both have blonde hair and blue eyes, both oppose Percy Jackson, and both struck the final, killing blow against the main antagonist of their respective series which killed themselves in the process. Though unlike Octavian, Luke redeems himself by sacrificing himself to defeat Kronos and makes peace with Percy before he died. Octavian's sacrifice was unintentional.
- Octavian has certain similarities with Star Wars character Borsk Fey'lya:
- He is a brilliant orator, who is adept at manipulating events to his favor.
- Both believed that the current leader of their government was less than perfect (Reyna Avila Ramírez-Arellano, Mon Mothma)
- Both made a selfish grab for power, dividing their people when they should have been united against a common foe (Gaea, Thrawn).
- Both were given advice by a onetime leader of their people that they ignored. (Octavian was advised by Praetor Percy Jackson to ally with the Greeks, Fey'lya was warned by former President Leia Organa Solo about the impending Yuuzhan Vong invasion.)
- Both are known for spreading discord about a particular group of people (Greeks, humans).
- Both had rivals that were wrongly accused of treason (Heroes of Olympus, Gial Ackbar)
- Both held the title of Senator.
- Both threateningly warned one of their colleagues that they were close to committing treason before they undertook a particular task (Octavian before Reyna departed for Greece, Fey'lya before Elegos A'Kla aided Leia in her fact-finding mission about the Yuuzhan Vong).
- Both held high-ranking positions in a new form of an old government (New Rome to the Roman Empire, the New Republic to the Galactic Republic)
- Both have been recognized as dangerous enemies by those who are supposed to be their allies.
- Both are selfish and power-hungry leaders, but also charismatic.
- Both also died in an explosion. However, Fey'lya redeemed himself by sacrificing his life to save lives; Octavian did not.
- Octavian is the first major villain in the three Camp Half-Blood series to be a legacy of Apollo and a skilled orator (the second being Nero). While Octavian is straightforward and discreetly insulting, Nero is far more sly, composed, and persuasive with his words. Therefore, it can be argued that Octavian is the less skilled orator of the two.