Throughout its four past seasons, we’ve seen Gotham’s pseudo-Joker featured heavily, though never referred to by his true name. However, with the chapter titled “ACE Chemicals” in the closing episodes of the show's final season, we will not only see the iconic chemical plant but also witness the legendary showdown between Bruce Wayne and Jeremiah Valeska.
“I mean it’s obviously a huge landmark within the mythos and it is relating to Jeremiah", actor Cameron Monaghan told ComicBook.com. “I don’t want to say exactly what happens and how it goes down but it’s really, really fucking cool. I’m excited for it.”
Although The Joker’s backstory has been intentionally ambiguous, one of the traditional fan-favorite stories was that the man who would be the Clown Prince of Crime was once a criminal masquerading under the moniker of the Red Hood. One night, an attempt to rob the ACE Chemical Plant was foiled by the vigilante Batman and during the conflict, the Red Hood fell into a vat of chemicals which eventually drained into the connecting sewer. What emerged from those waters would be known forevermore as The Joker, the Clown Prince of Crime and Batman’s arch-nemesis.
Monaghan originally portrayed Jeremiah’s brother Jerome, a deranged psychopath whose anarchy and mayhem placed him at constant odds with Jim Gordon and later, Bruce Wayne. His character’s death led to the reveal a twin brother Jeremiah, also portrayed by Monaghan, who hid his identity from the world, particularly from his brother. A simple “gift” from his deceased sibling infected him with a special brand of laughing gas which transformed Jeremiah in both mentality and appearance into an agent of chaos seeking to outdo his brother’s legacy.
Being the architect behind the No Man’s Land, Monaghan states that Jeremiah is at an all-time high, but despite his respectable infamy and new relationship, the character remains focused on his new project: Bruce Wayne. “ It's the one thing that's bothering him and nagging him because it's the one thing he didn't succeed at. That's what we see with him now is he's happyish but he's still unsatisfied because he needs to show Bruce how much he loves him, or his twisted version of love."
Airing Thursdays at 8 p.m. ET/PT on Fox, Gotham stars Ben McKenzie as James Gordon, Donal Logue as Harvey Bullock, David Mazouz as Bruce Wayne, Robin Lord Taylor as Penguin, Camren Bicondova as Selina Kyle, Erin Richards as Barbara Kean, Cameron Monaghan as Jeremiah Valeska and Sean Pertwee as Alfred Pennyworth. The fifth and final season is scheduled to premiere on January 3.