Edo Madara, seriously. I hate the simple fact that he's just too OP for the story, when he dies it'll be due to him not spamming his broken rinnegan meteors, and wooden dragons. I always thought that itachi would be the most absurdly overpowered person in naruto, but seeing all the OP crap Edo madarama has pulled from his ass, Tsukiyomi to me seems like moms good old apple pie, it was OP but at least it fit in, Edo madara is just a broken mixture of OP abilities for the hero to topple, kinda sad really.