I always liked the character Roy Batty from Blade Runner.
He’s utterly ruthless, sure, but at the same time he’s in the middle of an existential crisis: why am I the way I am? Why do I have to die?
He finally meets his literal maker, but gets no satisfactory answers. Then finally, in the last moments of his life, he gains an appreciation for not just his own life, but sees other people’s lives have value as well when he spares Deckard.
I absolutely adore characters with deep psychological issues that drive their actions, especially if all the questions aren’t answered and neatly wrapped up in the end.