Octavius is a Roman in the Roman Empire Diorama at the Museum of Natural History. He is best friends with Jedediah and is portrayed by Steve Coogan. With a strong heart and a cunning mind, Octavius appears in Night at the Museum, Night at the Museum: Battle of the Smithsonian and Night at the Museum: Secret of the Tomb.
Night at the Museum
Octavius is a Roman General in The Hall of Miniatures. He commands his legion to attack Larry using catapults and fireballs after Jedediah's attempts to take him down fails. In the beginning of the film, he is constantly arguing with Jedediah.
The next morning, Dr. McPhee asks Larry why Octavius' mini-figure is in the stockades in the Old West Diorama. Larry just comments that the mini-figures there were not happy that Octavius trespassed and locked him up.
During Larry's second night working as a security guard, after Octavius tries to break through the diorama box wall, Larry grabs Jedediah and Octavius in order to keep their dioramas from feuding. Larry tells them that they better behave or else they will end up like their "friends" from the Mayan Diorama (which Larry previously locked up). This doesn't work when Dexter steals Larry's keys again and runs past them resulting in both dioramas ending up in a feud again while the Mayans still remain locked up.
When it came to reclaiming the Egyptian Tablet from Cecil Fredericks, Gus, and Reginald, the two become friends when they learn to work together.
Near the end of the film, it is thought that he and Jed are dead when they crash the toy car they're driving with Rexy in pursuit into a snow bank with an explosion resulting in the end. However, they turn up later when Larry, Ahkmenrah and Teddy are making sure all exhibits return inside the museum. They are last seen driving in a new toy car hooked to one of Rexy's bones to make him chase them as Nicky rides on him.
Night at the Museum: Battle of the Smithsonian
Octavius is one of the exhibits that is send to the Federal Archives in the Smithsonian.
Octavius goes on a rescue mission to free Jedediah, who has been placed inside an hourglass by Kahmunrah. After acquiring the help of the Abraham Lincoln statue, he rides on a squirrel that he had earlier fought with to go and get the other exhibits, who have formed an Army. They share a friendly moment during Jedediah's time in the hourglass, before Octavius breaks it to free him. They then fight together against Kahmunrah, Al Capone, Ivan the Terrible, and Napoleon Bonaparte's men.
When they hear that they won the battle, they embrace each other in a hug.
Night at the Museum: Secret of the Tomb
Octavius and Jedediah become lost in the British Museum, and have to find a way to get back to Larry and the rest of the exhibits that accompanied him. When about to die in the museum vents Octavius asks Jedediah to hold his hand. Larry saves them by turning off the vents, and then the two miniatures venture through the vents until they jump down into a Pompeii display, which the miniatures do not realize is Pompeii until the volcano begins to erupt. They are saved by Dexter, who Larry sent to find the miniatures.
When first meeting the exhibit Lancelot, Octavius comments about his "hypnotic blue eyes".
Near the end of the film, when the tablet is corroding and all of the exhibits are beginning to freeze, Jedediah asks for Octavius' hand.