For me, it would be GLaDOS.
Portal 2 spoiler
She deleted the one remaining human part of herself because it was just too much to deal with. She releases you at the end of Portal 2 as a path of least resistance measure because “killing you is hard.”
What about you, what is your favorite media villain?
“He’s pissin! He’s pissin all over us! What does it taste like? It tastes like PISS! TO ME!”
My favorite scene of the entire series. The greatest show of all time.