Nathaniel Barnes (Michael Chiklis) from the Fox show “Gotham” has made a reputation for himself as a dedicated, unyielding, no-nonsense cop who will stop at nothing to do the right thing.

Despite being stabbed by former mayor Theo Galavan (James Frain) last season, he managed to survive. But something happened to him in the Season 3 episode “Mad City: New Day Rising” that might not be as easy to recover from.

Alice Tetch (Naian Gonzales Norvind) fell to her death during that episode, but before that happened, she warned people that her blood is toxic. While surveying the crime scene, a drop of her blood spilled on Barnes and changed his face.

Dedicated “Gotham” fans are now asking: What will happen to Barnes? Chiklis earlier teased that something really terrible will happen to Barnes that will “change him inexorably.”

“So there's some really cool stuff coming up for my guy. It's actually the reason I took the job,” he told Comic Book. “This is a guy who is a zealot for law and order. He's horrified. It's driving him a little crazy. He's really strident, unyielding, and unbendable, and something's going to break.”

Even before he took on the role, he already knew of this big twist that will happen to his character in Season 3. Chiklis said it actually helped him develop his character Barnes better.

“I knew that I could be a particular kind of man, knowing that I didn't have to worry about it becoming too one note or flat, because I was going to go somewhere,” he explained. “That's the wonderful thing about being in television anyway, because you get to explore a character over the course of many, many hours instead of the context of a two-hour film. There's some really cool stuff coming.”

Two other “Gotham” characters who have surprises in store are the Joker and Harley Quinn. Joker, played by Cameron Monaghan, was killed off last season. But executive producer Ken Woodruff said his character will somehow find his way back to the show.

“We are absolutely planning in Season 3 - but primarily in the mid to second half of Season 3 - to delve back into the mythology of the Joker, and characters that may or may not be the Joker - but more likely characters that are an amalgamation of what we'll come to know as the Joker,” Woodruff told TV Guide.

As for Harley Quinn, her reappearance will come as a surprise. “You may have already seen Harley as a person that you thought you had met and known for a long time. So we always reserve the right to sort of do that as well,” Woodruff told IGN.

“Gotham” airs every Monday at 8 p.m. ET on Fox. Gotham Nathaniel Barnes (Michael Chiklis) from “Gotham” finally embraced his dark side this Season 3. Photo: Fox