Gotham pulled off a monumental twist at the end of Season 4 earlier this year, when it killed off it's biggest villain, Jerome Valeska, in order to make way for his somehow even more evil brother, Jeremiah.

Both characters are inspired by very different comic iterations of Batman's nemesis, the Joker. And both Jeremiah and Jerome are played by actor Cameron Monaghan, who got to change his personality drastically when going from one to the other.

While visiting the set of Gotham's fifth and final season, ComicBook.com had the chance to chat with Monaghan about his time on the show, and we asked about the differences in playing both Jeremiah and Jerome.

"I've enjoyed them both for different reasons," Monaghan said. "It was cool with Jerome how it was so heightened and kind of cartoony and insane and I could go in any direction with it because he was just this weird ball of destructive energy. It's nice with Jeremiah to find some glimpses of humanity within him and to bring him back and to make him colder and more chilling in his [methods]. I'm also doing something a little different with this season as we're continuing to develop the character than where he was at last. He was very systematic and completely irrational last season. Now he's starting to, because he's starting to lose his sanity and he's slipping away without even realizing that he is. He has too much of an ego to realize that he's slipping. I get to play around more and move around more within the character and I'm having a bunch of fun with this part, too, and also where it's going is extremely exciting and I can't wait to hit a couple of these story weeks that are coming up."

"It's interesting with a guy like Jeremiah," he continued. "What, I think, separates him from Jerome is Jerome is very much just sort of destruction for the sake of destruction and he was sort of just kind of chaotic and didn't really have much of a plan. That's cool, but what's interesting with Jeremiah is he is sort of a craftsman and an engineer and a builder. He likes to create these elaborate systems. I think that's where he finds most of his amusement and his happiness comes from the building of things. It just happens that the things that he's building tend to hurt a lot of people in the process and he doesn't really care about that. He's singularly minded and extremely obsessive and right now he's very obsessed with Bruce."

Going into the fifth and final season, Jeremiah remains one of the show's major villains, as he's the one who caused the destructive No Man's Land event that altered the future of the city forever. His complicated relationship with Bruce will continue to evolve as the series barrels toward its upcoming finale, crafting the iconic rivalry that comic readers have long enjoyed.

Which Valeska brother to you like more, Jerome or Jeremiah? Let us know in the comments!

Gotham returns for its final season on FOX in 2019.