My least favorite character, but admittedly he is the king of villains in this manga up there with Orochimaru for me.
He is the worst type of enemy to have and probably had the most chance at being a successful villain. Everything was a careful plan and evil as hell, but his moves were all chess plays. If he wanted you dead, he would figure out the strategy to do so in secret. Or he would take "the rules" and justify insane things such as Genocide toward you. All while having the authority of Konoha behind him.
He's the scariest villain in this manga by far, he can either take you by surprise with manipulation, betrayal, and secrecy, or through politics/skewed moral compass, he could kill you within "his authority." I'm kind of sad that he had such a short term role, but jeez that is one bad dude and I think I might have been uncomfortable with him as the big bad. Just because he's thatevil.