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?
One of my favorites as an adult, and one that scared the living shit outta me as a kid. Jude Doom from who framed Roger Rabbit.