Karen Jennings is a supporting character in Season 2 of Gotham, appearing in the Wrath of the Villains arc. Appearing in the episode "Pinewood", she aids Bruce Wayne in his investigation of Pinewood Farms, a black-ops genetic engineering program run by Wayne Enterprises. She was portrayed by Julia Taylor Ross.
Karen Jennings lived a hard life; she was born with a crippled arm and her alcoholic father would regularly beat her. One day, Karen stood up to her father's abuse and pushed him down some stairs, causing him to break his neck. Despite acting in self-defence, Karen was convicted of murder and sent to Blackgate Penitentiary.
While in Blackgate, Karen was visited by members of Wayne Enterprises who told her that they could fix her arm. Karen agreed to take part in the Pinewood Farms program where scientists genetically reconstructed her arm, but rather than a normal human hand, she would instead gain a razor-sharp reptilian claw. When Thomas Wayne caught wind of the experiments occurring at Pinewood, he shut the program down and paid to put the surviving test subjects, including Karen, into hiding. From then on, Thomas formed a sort of father-daughter bond with Karen. He visited her on a regular basis, spent time with her, bought her gifts such as a music box for her birthday.
Two months prior to the murder of Thomas and his wife Martha, Thomas went to visit Karen following a break in at his home Wayne Manor. During the visit they were attacked by an assassin, but Karen managed to kill the man by slashing his throat with her clawed reptilian hand. Thomas then buried the man's body in the woods as he didn't want to alert the authorities to Karen's location.
Two years following the murder of the Waynes, Bruce Wayne and Alfred Pennyworth were able to track Karen down to a small cottage in the woods where she lived alone. Bruce asked Karen what she knew about Pinewood and the murders of his parents, but Karen claimed that she didn't know the names of the scientists who experimented on her. She did, however, lead Bruce and Alfred to the abandoned Pinewood site, though the trio were attacked by thugs sent by Professor Hugo Strange. Though the thugs were killed, the trio were then stopped by the police. Bruce and Alfred were released, but Karen was once again facing Blackgate.
With the help of Jim Gordon, Bruce and Alfred manage to hijack the prison wagon transporting Karen to Blackgate. Unfortunately, Strange was determined to silence Karen and sent Mr. Freeze to kill her. With his new armoured suit and enhanced cryonic weaponry, Freeze easily withstood Gordon and Alfred's small-arms fire. Not wanting Bruce to endanger himself any further, Karen willingly gave herself up to Freeze. Freeze used his cryo-gun to freeze Karen solid and then shattered her to pieces.