The protagonist of the series, as well as the narrator. His life is essentially one tragedy after another. Played by Derek Jacobi
- A God Am I: Subverted and played straight. He technically is worshiped as one, but he sure as hell doesn't want it.
- Awesomeness by Analysis: Used his historical knowledge to win battles and retrieve the last Eagle.
- Classical Anti-Hero
- Cloudcuckoolander: Although it's mostly an act.
- Crouching Moron, Hidden Badass: Claudius practically personifies this trope.
- Historical Hero Upgrade: Claudius and his desire to restore the Roman Republic, which is also somewhat unhistorical, since at that time there was no distinction made between the Republican and Imperial eras.
- Lonely at the Top
- Not so Above It All: A darker version of this trope: Claudius thinks he can remain separate from the murderous schemes absorbing his family. Unfortunately, when Claudius himself comes to power, he finds he must get his own hands dirty in order to survive.
- Obfuscating Disability
- Obfuscating Stupidity: Pretty much the only reason that he survives for as long as he does.
- Properly Paranoid: Claudius is convinced his (last) wife is trying to poison him. Oh, wait. She is.
- Reluctant Ruler
- Speech Impediment: Though it improves as he gets older.
- Ugly Guy, Hot Wife: With Messalina. It ends badly.
- The Unfavourite: His mother, Antonia, was always disgusted by him in comparison to Germanicus.
- You Should Have Died Instead: Claudius' mother lobs this at him after the death of her more accomplished son, Germanicus.
- Zero Approval Gambit
Augustus's scheming wife, who is willing to do ANYTHING to ensure that her son gets the throne.
Claudius's mother, and one of the few "moral" people in Rome. Though how sane she is is rather questionable.
Claudius's brother, and one of the few people to treat him with any compassion at all. Is eventually offed by his son.
Claudius's insane nephew, and the third emperor of Rome. Played by John Hurt
- 0% Approval Rating
- Blond Guys Are Evil: As opposed to his father's Hair of Gold, Heart of Gold. The resemblance is part of why the senators trust him initially, much to everyone's eventual horror.
- Brother-Sister Incest: With Drusilla. "And you know how I love my sisters..."
- The Caligula: Well Duh.
- Creepy Child: He becomes partially responsibly for the murder of his father when he was just hitting puberty.
- Creepy Crossdresser
- Enfante Terrible: Is already a murderer before he even hit puberty.
- Evil Nephew: Inspired the page and Caligula's actions even provide the page quote.
- A God Am I: In the more usual sense.
- I'm a Humanitarian
- Insane Equals Violent: Subverted. His violent/psychopathic tendencies are explicitly shown NOT to follow from his psychotic delusions: he's a killer from childhood, but doesn't go mad until after he becomes Emperor years later. Livia and other murderous characters are described as "mad" by other characters, but are not shown as irrational - even Nero, explicitly called "as mad as... Caligula", is clearly nothing of the kind.
- It Amused Me: Caligula has some shades of this - he does things like set up the young, beautiful Messalina with unattractive Claudius because he thinks it's funny.
- Large Ham: He is played by John Hurt, by the way.
- Manipulative Bastard: Right up until he loses all touch with reality as Emperor.
- Villainous Incest: With his sister.
Claudius's uncle, and the second emperor. Played by George Baker.
- 0% Approval Rating
- Berserk Button: Mention Agrippina's name around Tiberius and he'll want to murder everything in sight.
- Colonel Badass: A very capable general.
- Dirty Old Man: Have you heard about his "nymphs" at Capri?
- Happily Married: Until Livia ruins it.
- Kick the Dog: The scene where a woman he's raped is driven to commit suicide in front of her husband and guests is pretty much there to show us he's much less pitiable since he became emperor.
- King on His Deathbed
- Lonely at the Top: His ghost admits as much to Claudius.
- Momma's Boy: A very tragic example of one.
- Offstage Villainy: Most of his horrific actions take place elsewhere and we find out second-hand. This can be somewhat jarring as we only see him as a very sad and pathetic figure on screen.
- Pet the Dog: Tiberius's scenes with Drusus are there to establish that he did in fact have some redeeming points in his youth.
- Reluctant Ruler: Tiberius was fairly reluctant about the role his mother planned for him, too. The power went to his head pretty quickly, though.
- Sergeant Rock: "They say your drills are bloodless battles, and your battles are bloody drills." Tiberius, however, is fair, even sleeping without a tent if his troops couldn't have one.
- Sketchy Successor: Played with. As a heir to Augustus he is for the most part portrayed as a depraved tyrant; yet Claudius acknowledges that he was competent at governing the empire and that the majority of the population had little reason to complain during his reign, with only the minority suffering from his repressions. However, the trope is played completely straight during the last years of his reign, when he just stops caring about the administration of the empire whatsoever.
- Stuffed In The Fridge
- Training from Hell: His take on army training.
- Vorpal Pillow: Tiberius's fate.
- With Great Power Comes Great Insanity
- Yandere: After divorcing Vipsania, he becomes this. Subverted in that he was forced into a divorce, and his love of his wife was one of his few redeeming qualities.