because an uzumaki is a perfect vessel for the rinnegan(maybe because madara somehow knew that SO6P was an uzumaki??) because they possess strong body,great life force and vitality....zetsu aint so great
ok,and on this logic mean that Obito(who is not an uzumaki) is not verry compatible with rinnegan,am i right?
i think obito is compatible with the rinnegan because he possesses both uchiha and SENJU DNA....but madara had no one else than nagato at the time