Gotham's Jerome Valeska (Cameron Monaghan) has always been a wild card. Not much is known about his upbringing or what makes him tick, and his unpredictable behavior makes him one of the city’s deadliest threats.

Bruce Wayne defeated Jerome last time, but now the grinning lunatic is back and determined to plunge Gotham into chaos. However, he won’t be accomplishing that goal alone -- Jerome’s recruiting his own team of evildoers, beginning with Penguin.

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In advance of tonight's new episode "A Dark Knight: A Beautiful Darkness," Monaghan recently spoke with CBR about Jerome’s madness, pushing Penguin over the edge, gathering villains and whether Jerome is truly The Joker.

Robin Lord Taylor and Cameron Monaghan on tonight's episode of Gotham.

CBR: Where do viewers find Jerome when we meet him again?

Cameron Monaghan: He’s in Arkham Asylum. He’s healed up from his arc in Season 3. He has his face scarring. With that, we have a new evolution in his personality, voice and performance as well. He’s in Arkham and he’s kind of the king of his roost. He’s taken over in a lot of ways. The inmates are running the asylum. Jerome takes special interest in Oswald, and sees him as his own personal pet project to torture and push him as much as he can.

Let’s touch on that. Why is Jerome so invested in Oswald?

Penguin is this interesting figure within the city of Gotham. He’s this guy who has worked in the shadows and publicly. He’s skirted the line between lawful and completely chaotic or villainous. He’s risen and fallen multiple times in the ways that pretty much no other character can dream of. And, he’s established himself as a legend within the criminal circles. Jerome is fascinated by him and who this guy is. He is impressed by Oswald, and also sees him as utterly pathetic, at the same time.

Jerome wants to push him to his absolute extreme and breaking point. He wants to see if he can rebuild Oswald in his own image of insanity. He also wants Oswald to embrace his insanity or chaos, because he is forming a team of villains. Jerome wants to cause an uprising of chaos and destruction within Gotham City itself, with a whole legion of villains behind him. Oswald is his first domination, but certainly not his last, in this plan that he has.

Jerome wants to cure Oswald of his sad, mopey existence. How does he go about accomplishing that?

For all intents and purposes, he tortures him. He creates a public spectacle out of Oswald’s humiliation. Oswald has this newfound timidness about him as he’s been beaten over the course of the last few episodes. However, Oswald can’t possibly take it any more and snaps and he has to gain real aggression and think creatively to find some way out of this situation. As soon as he can find a greater way to deal with it, and to embrace the strangeness of the situation, then Jerome is happy with him. He’s going to torture Oswald until he gets to that point.

Speaking of strange, how bizarre was it filming a mime showdown between Jerome and Oswald?

That was fun. That’s something you are not going to see on any other show or movie. It’s a resolution to a scene and a conflict. That is Gotham firing on full levels of pure insanity. Robin Lord Taylor is a fantastic actor. That’s a scene that only works if both him and I really embraced the absurdity of it. We have this scene that is a lot of fun. I can’t wait for people to see that one. It feels out of left field, but it also feels tonally right for Jerome and his interactions.

Between Jerome and Oswald, there’s a lot of craziness going on. Are they kindred spirits, or is it only a matter of time before they turn on each other?

I think with two characters like this, there’s no way they are every going to be two peas in a pod. They are a bit of oil and water in their ideologies. They have this respect for each other in this reluctant camaraderie, especially with the reluctance being on Oswald’s part. Oswald goes from being antihero to full-on villain, but he has some semblance of conscious and some understanding of good. At least he has some belief in order. Jerome is pure, unadulterated chaos. He embraces it on its grandest level. Ultimately, two characters like that can only coexist for so long and be both a partnership and rivalry.

During his last appearance, Jerome targeted Bruce Wayne. How much of that obsession remains?

I think that rivalry between Jerome and his ideology, the ideology of the Joker, is going to be fundamental in establishing the story of Bruce Wayne within the show. Another established adversary is James Gordon, so we see them interacting with each other, too. Obviously, Jerome’s initial mission was to create chaos in Gotham.

We also see new characters and the exploration of some of Jerome’s past. We meet some key figures from his past. Jerome wants to eradicate his history and destroy all that. There’s one key figure he’s trying to chase down. I will say we are seeing an exploration of his motivations, his plans and his ambitions, but we are also personalizing Jerome and grounding him.

You mentioned Jerome is forming his own supervillain team. Who are some of his recruits?

We obviously have Jerome and Penguin. We have Mad Hatter. Jerome and Mad Hatter have a lot in common. Mad Hatter is almost a bit of a protégé or right–hand man to Jerome. There’s Scarecrow, who comes to play in a big way because of his expertise with chemistry and chemical composition. Fans of the comics know that would be very important to Jerome. We have Firefly, Mr. Freeze and Solomon Grundy. There’s a bunch of guys on this team. It’s amazing to see all these characters interacting with each other in live–action. It’s splashy and feels like its been ripped right off the pages or panels of comic books.

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There have been theories and speculations about whether Jerome is really “The Joker.” What is your take on the subject?

I think that he is in many ways. He is the proto-Joker. Jerome is the foundation on which everything else is built. He is the first wave of the ideology. In that sense, he absolutely is because he has all the same traits we will see echoed in new and interesting ways. I feel with Jerome, he was a love letter to the 75-plus years of the character of the Joker. He was an affirmation and a tip of the hat in a respectful ode to the comic book storylines that came before, and the performances -- both in live–action and in the animated series. A lot of the stuff done in all these different mediums, we wanted to pay tribute to the many different evolutions of the character, both physically and behaviorally.

But, we also wanted to craft our own voice and our own interpretation, and to bring a new direction that felt tailor-made for the Gotham universe, and someone who would feel dangerous in that world as well. You could look at Jerome both as the Joker and as not him. Ultimately, he has the key concept and key traits, but he doesn’t have to be singular within our canon. That’s what is fun about him. He is the foundation on which the other thing is now built on top of.

Gotham airs 8 tonight on Fox.