A place much like Camp Half Blood, dedicated to the Roman aspects of the gods and their children. It is composed of two parts, Camp Jupiter, the modern day continuation of the Twelfth Roman Legion, and New Rome, a city where demigods and their descendants can live peacefully. For the full list of characters, click here.
- "Surrender to Rome!"
Octavian is a legacy of Apollo, meaning he is descended from one of Apollo's demigod children. This gives him the gift of prophecy and a position at Camp Jupiter as its augur, who kills animals and interprets their innards to see the future. Due to this being set in the modern world and the impracticalities of gutting animals every time the future needs to be read, Octavian guts stuffed animals instead.
He is extremely ambitious and power-hungry, and aims to rise to the rank of praetor. He's willing to get his hands dirty in order to accomplish this, as seen when it's hinted he murdered Gwen. He also possesses a burning hatred of all Greeks, and calls for war against them. Reyna sees him as a danger to the camp, but as her nominal Number Two he finds ways to circumvent this.
- Ambiguously Evil: Well-Intentioned Extremist or power hungry Corrupt Politician? It is not helped that he eventually starts to crack, throwing mental problems into the mix.
- Ambition Is Evil: Dead set on becoming praetor so he can order a quest to find the Sibylline Books.
- Asshole Victim: Due to being a complete jerk with practically no redeeming qualities, a lot of people, Greek and Roman, in-universe and out, did not feel sorry for him when he got himself launched by a flaming catapult and died. Not even his most loyal bodyguard bothered to warn him that his toga was snagged.
- Blackmail: In The Son of Neptune, he's pretty clearly blackmailing Hazel into getting whatever he wants from her.
- Commander Contrarian: He disagrees with every decision Reyna makes.
- Corrupt Politician: He manages to win favor in the council by backstabbing everyone else.
- Creepy Blue Eyes: He's got dark blue eyes that compliment his generally creepy appearance.
- Dirty Coward: Best exemplified in The Blood of Olympus, in which he intends to destroy Camp Half-Blood using onagers without actually having to do any work himself and still being able to claim the glory for it. He also runs away once Gaia reveals herself after her awakening.
- Evil Chancellor: Seems to be acting as one to Reyna, as an active advocate of war against the Greeks. She quickly puts a stop to that. The moment she turns her back, he announces that they're changing their plans.
- Evil Counterpart:
- To Rachel. He serves the same oracular purpose as she does, but he's creepy and manipulative while she's straightforward and nice. They meet in the fourth book; it doesn't go over very well.
- He's also this to Will Solace, both are descended from Apollo, but while Will who is more of a medic than a seer wants to help make peace, Octavian wants to destroy the Greeks. Will explains that what Octavian was doing was not what Apollo would want.
- Famous Last Words: "Goodbye, Gaia! Goodbye, Jason Grace the traitor!"
- Fortune Teller: An augur, specifically, and using his insight into the future to twist Camp Jupiter politics to his advantage.
- General Ripper: He has this relationship towards the Greeks.
- Hate Sink: His jerkass behavior when he's first introduced and later acting purely on paranoia against the Greek camp and recruiting of monsters and sociopaths into his army in said paranoia make him this. Even his own bodyguard dislikes him.
- Hoist by His Own Petard: In the fifth book, he dies helping to destroy Gaea. He intended to hog all the glory of defeating her for himself, but instead his clothes snag on the ammunition of the onager he fires. He was able to do something useful for once.
- Jerkass: His rampant hatred of Greeks, hunger for power, and cruelty towards others more than qualifies him for this.
- Jerk With A Heartof Jerk: Never once shows a redeeming feature.
- Meaningful Name: Shares quite a few personality traits with the original Octavian, including ambition and being a smooth talker.
- Number Two: The augur is right below the two praetors in the chain of command, unfortunately.
- Prophecies Rhyme All the Time: In a series that mostly plays this straight, Octavian lampshades it by demanding that the prophecy Mars gives be cryptic and vague. Mars pulls out a grenade.
- Sanity Slippage: Suffers from this to a serious degree in The Blood of Olympus when he essentially dives head first off the deep end and begins recruiting criminals and monsters to help his cause.
- Seer: Guts teddy bears to see the future.
- The Sociopath: At one point, it's indicated that he stabbed Gwen in the back after the War Games were over, and he shows no remorse for doing such a thing.
- The Starscream: He's the traitorous second-in-command to Reyna.
- Trojan Horse: Invokes it when he advises the Romans to "beware of Greeks bearing gifts". Subverted, since that wasn't the plan to begin with.
- War Hawk: Is the most vocal in Camp Jupiter about going to war against the Greek demigods, and when Leo, possessed by an eidolon, starts firing on the camp, thereby giving him a reason, Octavian eagerly jumps on it and whips the Romans into a war frenzy.
- Well-Intentioned Extremist: Jury's still out on whether hes this or just a power-hungry bastard. Given his general attitude, though, it's most likely the latter.
- The Big Guy: He is very large, enough to crush rock with his bare hands.
- Charles Atlas Superpower: Being a son of Venus, none of his godly abilities augment his body. He got that strong through hard work.
- Commander Contrarian: He questions some of Octavian's decisions.
- Everyone Has Standards: As loyal as he is to Octavian, he's sickened by Octavian reinstating Bryce Lawrence as a probatio.
- Number Two: The second-in-command of Octavian.
- Punch-Clock Villain: He's a good guy, but he's very loyal to Octavian, who sponsored his entry into the legion.
- Shoot the Dog: He enables Octavian's death.
- The Alcoholic: Well, not quite...Percy: You let him drink wine?Hazel: Gods, no! That would be a disaster. He's addicted to red Kool-Aid. Drinks it with three times the normal sugar, and he's already ADHD — you know, attention deficit/hyperactive. One of these days, his head is going to explode.
- HeelFace Turn: He defies Octavian and tries to stop the Roman siege of Camp Half-Blood.
- Trademark Favorite Food: Red Kool-Aid.
- Benevolent Boss: She's quite nice to her subordinates.
- In the Back: She was impaled from behind with a pilum.
- Impaled with Extreme Prejudice: She's run through with a pilum during one of the war games.
- Not Quite Dead: Those tropes about her being impaled would have spelled the end for her, had Thanatos not been a bit tied up.
- The Optimist: She's described as being optimistic by her fellow legionnaires.
- Screw This, I'm Outta Here!: Not a combat example, but narrowly avoiding death caused her to step down as centurion and leave to attend college.
- Team Mom: She takes care of the Fifth Cohort and tries to keep their spirits up.
- Asshole Victim: Considering the pleasure and glee he took in torturing his victims, it's pretty cathartic when Nico lets loose on him.
- The Brute: He's one of Octavian's "attack dogs."
- Dirty Coward: He's very smug when he has the upper hand; however, when Nico lets loose on him, he's reduced to begging for mercy.
- Dragged Off to Hell: Courtesy of Nico, who turns him into a ghost and sends him straight to the Fields of Punishment.
- Screw the Rules, I Have Connections!: He would have been executed for his crimes, but his family's influence let him off with exile.
- The Sociopath: Reyna essentially calls him one in describing his sheer remorselessness and bloodthirsty tendencies, not to mention his murder of his centurion, which was why he was expelled in the first place.
- Voluntary Shapeshifting: A trait he inherited from his ancestor.
- Action Pet: They're guard dogs owned by Reyna and have killed various monsters.
- Cool Pet: They're basically robot dogs made out of gold and silver.
- Gem Tissue: Both have rubies for eyes.
- Heroic Dogs: They're dog automatons and follow Reyna, who is a hero.
- Living Lie Detector: Both can detect lies.
- Red Eyes, Take Warning: Both have rubies for eyes and are guard dogs for a reason.
- Barrier Warrior: Hes the last line of defense for New Rome.
- Berserk Button: When people dont follow the rules, Terminus gets very, very angry. Also, do not contradict his belief that his statue has arms.
- Butt-Monkey: People like to crack jokes at his expense.
- Chekhov's Gunman: Just there for comedy relief? Think again.
- Heart Is an Awesome Power: He has jurisdiction over borders, and this is used in the fight against Polybotes.