As FOX’s “Gotham” continues to chug along and introduce us to new characters from the Batman mythos–this week they debuted a young Harvey Dent–executive producer Bruno Heller spoke about what other characters we can expect to show up soon and who definitely won’t be appearing.

“We’re going to do a prenatal origin story for Robin down the line,” Heller tells EW. “There are no MRIs involved. There’s an episode coming up where we learn how Robin’s parents got together.”

Heller went on to elaborate on the upcoming episode set to introduce Jonathan Crane, AKA Scarecrow.

“This is not a kid being a looney Scarecrow, this is a couple episodes about how that character has evolved — everyone’s character is formed in their childhood to some degree or another.”

He went on to talk about their philosophy for introducing new characters, and to reveal that the Joker’s psychiatrist turned lover Harley Quinn won’t be making an appearance.

“One of the things about the size and scope and ambitious of this production is that — it’s not that there’s lots of chefs in the kitchen, but there’s a lot of people with opinions and views and inside knowledge. That aspect of the show — which characters to use and when — is a source of constant discussion. And that may well have been an issue that came up and was dropped. We haven’t got Harley Quinn in it. Riddler’s girlfriend is coming up. And Harley Quinn is definitely planned for later on, but so far no….You can’t just keep pumping these characters into the show in a comic book sort of way, because you get the Super Friends effect — which isn’t a bad effect, but then you have spaceships and need to go underwater and get wacky villains and the rest of it. You have to work as a character piece first. First it has to be real.”

Heller also confirmed earlier reports that they’ll be playing with viewer’s expectations of The Joker by introducing a number of characters that could become the Clown Prince of Crime. What Batman villains do you want to see show up on the show? Let us know in the comments!

“Gotham” airs Mondays at 8 P.M. on FOX.