ever since i first read about pein i had the theory that all the bodies that weve seen weren't him at all, but puppets or people he controlled using some power obtained through the rinnegan (since it lets him use every jutsu ever) and that part of the technique requires him to put those piercing/black things on the host to be bale to controll them. And the fact of what it says in the first post mixed with the fact that he got a new body, almost nearly confirms my theory