i think that it was not MS because he opened the seal while fighting and not during the time naruto was with jiraya. and he said that before the fight.
who would be stronger? him or nagato?
they are both in their prime and u cant tell me that itachi cant find the real nagato because he is hiding.
this is because itachi can see chakra using his sharingan.
The prophacy stated that naruto will fight a man who's power lies in his eyes.
Do u think that the man is actually tobi not sasuke.
by the way, as this series procede i am getting the feeling that tobi is actually obito's body but not obito himself.