Ego, Guardians of the Galaxy Vol. 2
He gives the mother of his child a BRAIN TUMOR just so that he doesn’t have to deal with the pain of breaking up with her. Then he kills all of his children on his quest to take over every single planet in the entire galaxy. Just because he tosses the ball around with Peter Quill a little on the planet he built as a god doesn’t exonerate him from all the murder he committed. Also, he put a bad spin on Brandy (You’re a Fine Girl) by the Looking Glass, which is arguably one of the best songs ever recorded. Fuck that guy.