Now that Cameron Monaghan's psychotic Jerome has been replaced by his twin brother, Jeremiah (also Monaghan, natch), Gotham's about to face a whole new madman - one who's more reserved and plotting than his unhinged twin.

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With two episodes left in Season 4, I spoke with Gotham EP/showrunner John Stephens about the "Joker" swap - the switch out that saw Jerome infect his sibling with a modified version of his madness - along with how the show's upcoming "No Man's Land" Season 5 reboot will affect Jim Gordon and the overall plans for ending the show with the arrival of Batman.In "One Bad Day" - airing Thursday, May 10th - Jeremiah Valeska looks to detonate a series of powerful bombs all over the city. Surely, a huge destructive scheme befitting the Valeska name, but is Jeremiah a...saner version of the Joker? Stephens opened up about the choice to swap out the brothers. "Some of it was born out of the fact that we could never have the Joker-Joker character on the show," he revealed. "We wanted to try to develop a new character who could embody another element of the Joker persona. It felt like Jerome, as great as he was, had gone as far as we could go with him. So we spoke to Cameron [Monaghan] as well and discussed doing the character as a version that's just as insane as Jerome, but who controls it in a different way. And to do a quieter and scarier version of the lunatic. Someone who's cut a bit more from the Hannibal Lecter cloth rather than the chaotic anarchy cloth.""We also wanted to create someone who had a particular point of view regarding his attachment to Bruce," Stephens added. "You know the Joker always has that connection to Batman, like frenemies or brothers or two sides of the same coin, where they can't live without the other one. We wanted that to be a part of what was driving Jeremiah here. Jerome was his false brother and Bruce is the brother he should have had and the two of them will be bonded together in the way Batman and Joker will be bonded one day. This is what pushes us forward to the end of the season."So with this all being born out of the show not being able to portray the real Joker, Stephens confirmed that neither Valeska is the true Joker who will one day plague Batman. "Jeremiah is not the Joker," he said. "The other characters are who they are. Mad Hatter, Scarecrow, etcetera. But no, he isn't the Joker. What we've always gone with is that Joker is somewhere out there, anonymous and unformed, in Gotham, and he's watching the actions of Jeremiah and Jerome and possibly even another one, on his way somewhere down the line, and he's adopting them as inspirations as the person he'll one day become."All this implies too that Batman, one day, will face Joker and realize that he reminds him of the Valeska twins from years before. "I guess that's true," Stephens laughed. "I'd never really considered that."With the Season 4 finale titled "No Man's Land," Stephens spoke about what the upcoming storyline, a spin on the comic book arc, will mean for Jim. "Jim may be at a breaking point, to a degree," Stephens said. "We're not going to see him break this year. A lot of his emotions as we wrap things up in Season 4 involve the Lee/Nygma/Jim triangle and the fact that he questions his own ability to act within the parameters of the law.""By the end of the finale, and pushing into Season 5, where we go into our version of 'No Man's Land,' where Jim is left alone in Gotham, there is no law and he actively has to decide where the line is going to be himself. Like, there's no law except that which he wants. He'll have to confront the darkest version of himself."In most Batman lore, the Caped Crusader's foes arrive on the scene after the does, as a response to his costumed vigilante actions - as a form of escalation. On Gotham, it's the opposite. The city's already crazy and most every member of Batman's famous rogues' gallery is already at large. Batman is a response to them. "A lot of that was motivated by very self-serving purposes," Stephens admitted. "If we'd adopted the traditional model we would have never gotten to use the characters the way we wanted to use them. We really wanted to see them come about. So the idea here was that we really wanted to see our villains and so our villains will then become the reason why Batman would eventually enter the picture."Presumedly, the show will end, as most fans expect, with the reveal of Batman in the final frames. A silhouette or a view from the back of Bruce putting on the cape and cowl. So how do you plan for that type of ending while also plotting out a season of TV that relies on Fox granting you more seasons? "We're not planning for the ending yet," Stephens stated. "Not too much. But we have an idea. So when we know that the show is actually coming to an end and Fox tells us that it's the last season, we have an arc - a six-episode arc - that will tell a final story. But it's for sure not going to take place over the next two episodes."

Matt Fowler is a writer for IGN and a member of the Television Critics Association (TCA). Follow him on Twitter at @TheMattFowler and Facebook at Facebook.com/MattBFowler