Gotham: Killer Croc

As well as a grown up Poison Ivy, a Mad Hatter and a Fish Mooney loose on the streets of Gotham, Jim Gordon must also face Killer Croc in season 3 of Gotham. Executive Producer John Stevens said,

"A lot of those characters, because they’re in Suicide Squad, we’re not going to be seeing them this season. We will be seeing proto-versions of some of those characters; we’ll see a proto-Killer Croc version. And we’ll be seeing a character — perhaps not this season, but in times to come — who can be a forerunner for Harley Quinn."

The Killer Croc character is most likely one of the creatures in the bus with Fish Mooney that were released into the streets of Gotham at the end of season 2, so he then probably has a link with Indian Hill and Hugo Strange.