I'm not sure who 'Julius' specifically is in relation to 'Pulp Fiction' as the movie doesn't have a character named Julius in its main storyline. It could be a name made up for some sort of fan theory or an inside joke among those who love the movie.
The Death Eaters could still be a major threat. Even with Voldemort gone, some of them might be trying to revive the dark ways and see the wizard king as a big obstacle in their path.
Probably some rival characters as well. These are other wizards who are also competing for the title of Wizard King or have their own agendas that conflict with the protagonist's. Their interactions with the main character add a lot of tension and excitement to the story.
Brutus is another important character. He is a noble Roman who is conflicted. He loves Caesar as a friend but is worried about his ambition. He plays a crucial role in the conspiracy to assassinate Caesar, believing it is for the good of Rome. His character is complex as he struggles with his moral decision.
Well, there are many fictional works out there, and Julius as a villain could come from various sources. It could be in a mystery story, a sci-fi adventure, or a medieval epic. Without more details, it's hard to pin down.