Jerome (Cameron Monaghan) is back on Gotham, which means only mayhem can lay ahead.

For the time being, Jerome has his eyes set on Penguin (Robin Lord Taylor), trying to break through whatever remains of Hugo Strange's (B.D. Wong) brainwashing to bring the truly evil Oswald out to play. He succeeds in making Oswald crack in his first episode back, but it's clear that Jerome has a much bigger plan in the works.

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Jerome is currently holding up well in Arkham Asylum, but his end goal is to turn Gotham City itself into the asylum and create chaos for the entire population. The details of how that is going to happen are still being kept under wraps, but we know that Penguin has a part in it and the end result will be The Joker.

TV Guide talked to Monaghan about Jerome's return and the birth of Batman's legendary foe below.

<p>Cameron Monaghan, <em>Gotham</em> </p>

Cameron Monaghan, Gotham

Every time we see Jerome he's never exactly the same version of him that we've seen before. Can you talk a little bit about how he's evolved this time that we're seeing him?
Cameron Monaghan: Yeah. Well, I think that because we're basing it off of over 75 years of the comics, the character of The Joker and any character in Batman just evolves very rapidly depending on who's writing him, who's drawing him, and what story he might be in. We kind of wanted Jerome to be reflective of that [legacy] in the performance. I think that in the first season he is very much a kid just kind of revealing himself and the second season he's more in his teenager phase and this sort of young, punk guy. In the third season he's sort of like this young, upstart, sort of professional kind of guy.

Now we're seeing him kind of mature and really come into his own in personality, and behavior and ambition. This is him more secure in his behavior than we've ever seen him, so we wanted to let him sort of evolve his voice. With the look, obviously he is now fully scary and he's got all this crazy hair, and all of this stuff going for him.

Jerome does have a very keen interest in Oswald in this first episode that you're back. Can you talk a little bit about how their relationship is going to develop and how Oswald is going to fit into Jerome's overall plans in the back half of the season?
Monaghan: I think that Jerome is fascinated by Oswald in sort of the way that he's interacting with the city in the times that he ... He empowers the fact that he's lost it. I think that he finds him fascinating and also a bit of a pet for him — a pet project. He kind of takes him in and he wants to really unleash what he believes is his true potential and his true insanity.

In Jerome's introduction we see him decide to torture Oswald to his breaking point, but from there he wants to create a collection of villains, of the worst of the worst within the city, because he wants to bring a new level of chaos to Gotham itself. He is starting this mega team that he's spearheading. He wants to get all the villains together to terrorize people and to turn Gotham City into a madhouse of a sort. Oswald fits into his plan in that sense, but also I think that he has just a personal liking for him and for pushing his buttons.

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We keep seeing Jerome flashing these Joker playing cards around, is he actively planning for the birth of that character or is it gonna be a side effect of what his grand scheme is?
Monaghan: He is absolutely in the impetus for the creation of the Joker within the Gotham universe and within that game. Me being the show's proto-Joker. Being that sort of first wave and the first interpretation of him, but from there just be a brand new evolution... I can't say exactly how it is that comes into play, and who this new person is, or what exactly it is. [Jerome] is the first wave, but he's not the only one. He definitely is the person in the foundation of Gotham's Joker version.

Jerome had some pretty intense unfinished business with Bruce Wayne last time we saw him, but it seems like he's biding his time in Arkham. Does he have plans to reunite with Bruce and does Bruce sort of fit into this master plan of his at all?
Monaghan: Yeah. I think that a plan can only be used to a certain level with Jerome, because as much as he might have grand ambitions, and he certainly does, he's willing at any time to change his priorities to do pretty much whatever amuses him within that moment. One of his most valued pleasures is to destroy and terrorize Bruce and he absolutely is planning to come after him in some way. We do see them interact in these upcoming episodes.

How do you feel about Jerome building up to the Joker even if he doesn't become the Joker himself?
Monaghan: Well, he's the Joker in many ways. He's the proto-Joker for this show, he's reflective of the ideology of the character and the creation of the foundation of him. From that foundation they're gonna need to build on top of him as well. But, I think that with Jerome what we really wanted him to do was [begin] an origin story of sorts. We wanted to pay tribute to the many different comic book arcs, the many different appearances in the animated series and also the live-action performances as well. Now, with bringing in this new character we wanted to now put our own interpretation on the table and add our own twist, and bring some new voices to it as well.

Obviously, it's in some ways sad to not be Jerome the sole voice of the Joker anymore, but in many ways I think it's really exciting because now we're getting to do new things and we're getting to be unpredictable. Which, I do think is the most important facet of the Joker is to make sure that he's not too predictable and you don't know exactly where the story's gonna go with him. I think that overall it's really exciting.

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What are you most excited for fans to see in this back half of the season?
Monaghan: Oh gosh. There's a lot coming up that's really exciting. We see an escalation in the story that we've never really seen before. Obviously, the show is fun, and it's goofy, and it embraces the ridiculous aspects of the fact that it is ultimately about a guy who is going to wear a bat suit one day and punch bad guys in the face really, really hard. There is something inherently ridiculous about that, but what we really want them to do is especially towards the end of the season is make sure that we take it to a grounded point.

I think that if there's any character that brings a level of threat, or seriousness, or stake to a Batman story, it is the Joker. He's the guy who will beat one of your characters to death with his crowbar or shoot them in the spine. He's that force of nature that comes in and I think that I'm most excited to see our new guy come in and be ... As well as Jerome. Jerome and this new guy are both sort of these mechanisms of fate. They're sort of like the hands of fate coming in and forcing the city into what it's going to be and forcing Bruce into a role that he's going to have to take.

He's constantly pushing things more towards the end and he's causing damage both on grand scale on a mass level, but also in a deeply personal level. We're excited to see how people react to the escalations of these events in so many different ways. It's really the most ambitious that the show has ever been. These couple arcs of the season really raise the stakes in lots of ways. I think it's gonna be really cool.

Gotham continues Thursdays at 8/7c on Fox.