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?


Catherine Foundling, the Protagonist of A Practical Guide to Evil.
But I don’t know if this counts. Catherine has only the best intentions and many Heros are kinda Dicks in PGtE. She definitely causes a lot of (what she considers) necessary suffering to end unnecessary suffering. And in-universe she undeniably is a Villain, but as the villain protagonist it’s hard to argue that she’s on the same page as villain antagonists.
I like the black knight from the same work.
Oh yeah! Soooo many of the things that make Cat cool she learned as the Squire to the Black Knight. I love his worldview, his genre-savy and blunt pragmatism.
His little speech of why he chose Catherine over Akua is just Chef’s kiss