But how? Don’t get me wrong, he’s a compelling character, but he’s not a credible villain.
He’s an unpredictable loose cannon, which after six movies of Palpatine and two movies of diet Palpatine is a novelty. Anyway, I don’t think a villain needs to be an unambiguous personification of evil to qualify as a villain. An emotional wildcard with warped intentions and poor impulse control can do just as much damage as a malevolent puppet master.