"Gotham" is getting darker and more violent as more villains join the cast in the season 2. What Fox's series has on the list are Penguin, who proclaimed himself as the "King of Gotham," Theo and Tabitha Galvan, who reportedly will rise to power in the new season, and Barbara Kean, played by Erin Richards.

Kean, an art gallery owner from a rich family, was one of the good guys until she was abducted and brainwashed by The Ogre, a serial killer. She ended up being locked up in Arkham Asylum after killing her parents and attempting to murder Leslie Thompkins, Gordon's girlfriend.

Now that she's in the same asylum as the Joker is, many are speculating that she will become "Gotham's" Harley Quinn.

"She could be anything right now," she said during the San Diego ComicCon interview. "She could be her own villain."

"But I'd like to see how Margot Robbie is going to come out with that one," she added. "She'll be great."

Richards is not thinking of who her character might become, according to the Comic Book Resources. She said that Kean will meet all these characters in the series, including the Joker.

They will all play a big role in the development of her probable role as a villain. Richards said her character knew the weaknesses of everyone and she would use those to grow in power.

Meanwhile, "Gotham" fans are loving Penguin, but many are curious if he would be able to keep his title as the "mob boss" now that more villains are coming his way.

Take for example Tabitha, known as the Tigress, and Theo Galvan, who will be coming back as regulars in the upcoming season, The Bitbag learned. 

The Mad Hatter and Mr. Freeze are also set to join the villain cast. It looks like this is going to be a tight competition for Penguin.

The show dropped a hint that this season will showcase more suspense, action and casualties as it released a promotional photo showing the young Bruce Wayne exploring his future cave. At the bottom part of the title, it had the words "Rise of the Villains," Latin Post reported.

"Gotham" season 2 premieres on Sept. 21 on Fox.