Fox's Gotham has already included a slew of iconic Batman characters but it looks like things will be slowing down as more characters are only introduced gradually.

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Gotham show runner Bruno Heller spoke with Entertainment Weekly recently about the various Batman universe characters who have not been introduced in the series yet.

"We're going to do a prenatal origin story for Robin down the line," Heller quipped, saying that "There are no MRIs involved. There's an episode coming up where we learn how Robin's parents got together."

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Robin is a great deal younger than Batman/Bruce Wayne so introducing him at all would be a bit out of line with continuity. Another character much younger than Batman is Harley Quinn, though it looks like the show will be introducing her in an upcoming season.

"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," Heller said, discussing Harley Quinn. "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."

He noted that while the show was originally "front-loaded" with a slew of Batman characters, such as the Penguin, Catwoman, Poison Ivy and the Riddler, they are looking to introduce characters in a more "measured" way, rather than throw everyone at the audience too quickly.

Gotham airs Mondays at 8 p.m. ET/PT on Fox.

Watch the promo for the next episode of Gotham here:

Tags: Gotham television fox