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?
Desty Nova from alita (Not the generic villain Norton played in the movie, the one from the comic).
What’s so great about him is that he doesn’t have any interest to rule or destroy, but he loves to set the stage for interesting happenings and watch them unravel. But he loves flan more.