people are going to say raikage and there reason is going to be that raikage can speed blitz kabuto and kill him before he uses edo tensei. for some reason people think raikage can kill elite shinobi with ease doing that when we've never seen it (kisame doesnt count because kisame wanted it to happen). jugo had time to block raikage and sasuke had time to counter raikage. i'm pretty sure kabuto would have enough time to summon itachi and nagato and then the battle is over. kabuto wins