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?
“Look at you hacker, a pathetic creature of meat and bone, panting and sweating as you run through my corridors.”
Has a similar feeling to Mark Twain’s The Mysterious Stranger