Aside from Mr. Freeze (Nathan Darrow) and the returning Fish Mooney (Jada Pinkett Smith), new names have been added to the growing list of villains in the back half of "Gotham" season 2.

According to Screen Rant, the Mad Hatter and Clayface will soon join the rest of the baddies in making life hell for the citizens of Gotham City. For "Batman" aficionados, the Mad Hatter is Jervis Tetch, a competent research scientist who has delusions of becoming the character in the Lewis Carroll classic "Alice in Wonderland." Gifted with an exceptional skill in hypnosis, Tetch has committed a lot of crimes. He has an odd penchant for hats and headgears, and he specifically likes Batman's cowl.

Clayface, on the other hand, was once a popular actor named Basil Karlo. When he learned that a new star would take his role in one of his classic movies, he became mad. He used the mask of the villain in the film, Clayface, and proceeded to murder the cast and crews. Eventually, he became the massive monster of clay after using a substance known as The Mud Pack. When Batman and Robin apprehended him in the comics, he got sent to the Arkham Asylum, only to escape care of Joker's brilliantly planned heist.

During the Wondercon panel for "Gotham" in April 2015, show producer John Stephen mentioned that both villains would be heading to the city.

"Clayface and Mad Hatter are both villains we're going to bring in as well. They both have great backstories and great personalities. Clayface especially is a character I want to explore the origin of," he said.

Meanwhile, the new promo for the upcoming midseason premiere shows Mr. Freeze taking his first victim upon return to Gotham City. In the clip, a man is fleeing in a back alley. When he realizes that he cannot steal a car to get out of there fast, he chooses to hide in a narrow crevice. Then comes Mr. Freeze, with his trademark glasses and cryogenic gun, calmly hunting the target. As expected, the villain points his weapon to the cowering man and freezes him.

"Gotham" season 2 will return on Monday, Feb. 29, at 8 p.m. EST on FOX.