'Gotham' Executive Producer Explains How They Decide Which Villains To Put In The Show

Fox's most-anticipated new show of the fall season is definitely Batman prequel series, "Gotham."

The show will serve as an origin story telling not only how the billionaire Bruce Wayne eventually becomes the Dark Knight, but also how his most compelling foes transformed into some of the Caped Crusader's most dangerous villains.

Fox has already revealed a few of the characters from Batman's Rogue's Gallery who will appear on the show: Selina Kyle (the future Catwoman), Edward Nygma (the future Riddler), and Oswald Cobblepot (the future Penguin).

So far, there hasn't been any mention of Batman's biggest future nemesis on the show, the Joker, but that could change.

During a recent media conference call with "Gotham" executive producer and writer Bruno Heller ("The Mentalist") explained there's no limit to the potential villains who could appear on the show in the future.

"The simple answer is: No. We're ready to go with any of them [Batman's villains]," said Heller.

"We haven't excluded anyone from the mix potentially, but generally what we're looking at is characters where there is some drama or a story behind how they got to be the way they are," added Heller. "We're looking for characters who live in the real world of Gotham as opposed to the even more super real world of Metropolis if you like. It's not about super powers, it's about super will, if you like. We veer towards those characters who are interesting as people, rather than interesting for their particular power or their particular gimmick or their costume."

Heller hinted you may not see every favorite on screen. Some are just simply harder to adapt.

"There are certainly characters that would be very difficult to put on the screen. That crocodile guy is a tough one - although we may go there," Heller explained.

The "crocodile guy" he refers to is Killer Croc, a man born with a condition that caused him to slowly transform into a crocodile. (For those not familiar with Batman mythology it sounds a bit silly.)

Here's how the character appeared in the Emmy winning "Batman: The Animated Series."

It's also interesting that he dropped the Metropolis. While that could certainly mean nothing, could we be seeing a young Clark Kent wandering around, too?

"Gotham" premieres on Fox Monday, Sept. 22 at 9 p.m.

Watch a trailer for the series below.