- "Pompey said he would have my head for going against the Senate but when I lead my army across the Rubicon, Rome will welcome me as a god."
- —Julius Caesar[src]
Gaius Julius Caesar, simply known as Julius Caesar, was a highly renowned Roman ruler and general. He ended up as an anachronism in 2017's Aruba, before being returned to his time and trying to correct his mistakes through the stolen book from the future, "Rise of Rome".
Caesar ended up in Aruba as an anachronism when the Legends changed history using the Spear of Destiny. Caesar managed to escape from Mick Rory's capture and attempted to rally a group of Roman soldiers, unaware they were simply a fraternity dressed in togas. Caesar was eventually captured by the Legends and sent back to his timeline where he stole "Rise of Rome", a book of Roman history from Dr. Nate Heywood, learning about his assassination in the "Ides of March" chapter and planned to kill two of its' biggest conspirators, Cassius and Brutus, before they could kill him. This led to Caesar never being killed and conquering most of the world which changed future events. The Legends, along with the Time Bureau, managed to subdue Caesar and his forces, erasing their memories.
Thanks to the knowledge from "Rise of Rome" Julius was able to empower Ancient Rome to such extent that the Roman Empire never fell, allowing for the creation of such a historical aberration as "Hesperia Magna", a Roman-colonized territory of North America that was originally supposed to become the United States.
Prior to his march on Rome, Julius anticipated interference from the Time Bureau and thus set a trap by emptying his camp, leaving "Rise of Rome" on his table. When two Time Bureau agents led by Ava Sharpe arrived to retrieve the book, Julius ambushed the trio, managing to capture Sharpe while her compatriots fled through a portal back to the Waverider. Deciding to spare Sharpe, Julius held her captive as he began his march towards Rome, only to be attacked by the Legends. At the end of the battle, Julius was knocked out by Rory as payback for breaking his nose. Afterwards, the Time Bureau erased the memories of Julius and his army, averting the alternate timeline.
Julius Caesar was a man of great pride and megalomaniac ambitions, seeing fit to conquer the whole known world regardless of the location or the time period he was in. His pride was hurt greatly after being defeated by a woman, though seeing as she later sought his advice his opinion changed on trying to make Sara Lance, the "Amazon warrior" that she is, into his empress to conquer the world with. Julius was unrelenting in his ambitions and focus, refusing to give up, and giving the advice to do the same to Sara. He considered himself fair and truthful, warning his enemies of the impending revenge should they let him ago after a wrongdoing he suffered at their hands.
- Genius level intellect/Master tactician/Leader: Julius was a man of high intellect, able to become a Consul of Rome, leading its armies, and later take over as a dictator. Even stuck in a foreign place at a different time he was barely distraught and ready to conquer a new world. Julius conquered many territories, most notably Gaul, and took on Rome itself despite the orders of the Senate. Using his experience with taking risks he was able to advice Sara on how to deal with the Time Bureau. Aside from the knowledge of strategy, he was also a direct tactician, baiting the agents of Time Bureau into a trap and capturing one of them.
- Indomitable will: Julius never gave up under any circumstances and always sought to take revenge on his enemies. Stuck between a seemingly impossible choice he pressed one, ready to risk everything.
- Skilled swordsman: As a member and leader of the Roman army, Julius was trained in swordsmanship, though not on the level of a League of Assassins member, leading to his defeat at the hands of Sara..
- Master hand-to-hand combatant: Julius mastered unarmed combat to such a level that he was able to escape his bounds and to ground Mick Rory, who is a master fighter in his own right, even when Mick had dominated the Roman leader during most of the fight. But he was easily beaten by Sara Lance and later defeated by Mick in a single punch during their second clash and also got his nose broken. In his third confrontation with Mick, he was easily beaten by the pyromaniac.
- Knowledge of future languages: due to the nature of anachronisms caused by time travel, Julius was able to flawlessly speak modern English while in 2017's Aruba, a language that did not exist in the times of Ancient Rome.
- Knowledge of future history: Picking up "Rise of Rome", Caesar was able to correct his mistakes seeing how the history would unravel.