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?
Forest Whitaker as Jon Kavanaugh in “The Shield”
He made me so viscerally upset. I saw it almost two decades ago but I still remember how strongly I felt