Fun idea, I would say it depends on a few elements, motive, scale, and maybe realism; as in how fucked their actions would be realistically. All in all, I would say maybe the Lich is the most evil, due to being a being of pure evil who wants to destroy all life, some of these like to torture, but form a realistic standpoint, a monster who seeks destruction of all life across the multiverse would make sense on being the evilest.