Nyssa al Ghul (Gotham)

"You won't die yet, my warrior. There is so much more for you to do."

- Walker to a wounded Eduardo.

Theresa Walker is the overarching antagonist in the fifth and final season of FOX TV series Gotham. She is a rogue corrupt government agent who brainwashed Edward Nygma into massacring the Haven and sending Eduardo Dorrance to enact her own mysterious agenda for the city.

She was portrayed by Jaime Murray, who also played Carmilla Pines in Sleepy Hollow, Lila West in DEXTER and the Black Fairy in Once Upon a Time.

Biography
Nothing is yet known about Theresa Walker, even before the destruction of Gotham's bridges. What is known is that years before, she rescued Eduardo Dorrance, an army officer from the prison Peña Duro and apparently gave him a new purpose.

Following Ra's al Ghul and Jeremiah Valeska's actions of turning Gotham City into a No Man's Land, Theresa had Hugo Strange brainwash and revive both Edward Nygma and Lee Thompkins to do her bidding. According to Eduardo, Walker spent months trying to convince her superiors that Gotham was filled with nothing but criminals and that they needed to step in an wipe them out. He also said she was close to fully winning them over.

When Wayne Enterprises sends a chopper to the city with supplies, Theresa uses Edward to shoot the chopper down with a rocket launcher. Later, she responds to Jim Gordon’s message, saying that she has help on its way to him. After Gordon had a Haven built for hundreds of innocent Gotham civilians, Walker's superiors started believing that the city's criminal underworld was not that bad. Therefore, to try and change their opinions, she has Nygma fire an RPG at the Haven, blowing it up and killing everybody inside.

Walker then sends Eduardo and his Delta Force to hunt down Nygma and have Gordon kill him to ensure his loyalty, Unfortunately, Gordon refuses and escapes, forcing Dorrance to have Nygma kill him. Eduardo informs her of Gordon's escape and their loss of control over Nygma. She sends Lee to the city to ensure that he makes an exchange. Eventually, the press learnt of Walker's actions and she was exposed. Being forced to arrive at Gotham to ensure her plans, she finds Eduardo fatally impaled and gives him a defibrillator. She then has Lee kill Gordon, but this also failed.