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?
There’s something genuinely compelling about SHODAN.
They’re malignant, objective evil, yet when they talk about their goals and ambitions, they seem almost benevolent, which makes them even more unsettling.
It’s like something telling you to calm down while it’s sawing off your legs to replace them with mechanical versions because it’s “improving you”.
You didn’t ask to be improved.
Similarly, the cybermen just want to upgrade everyone.
“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
SHODAN introduced my prepubescent brain to the concept of being “scaroused”.