there are still speculations on who Tobi really is! from my point of view, Tobi is the greatest mystery in the whole Naruto setting!... he claims to b Madara, yet the real Madara was resurrected through Kabuto's EdoTensei. when he met Naruto, he said "I AM NO-ONE! I DON'T WANT TO BE ANY-ONE".. he made it even hard to tell who he is. Once, when he was trying to get Nagato's eyes, he told Konan "i'm here for the eyes! it belongs to me"< that proves he has been here for a while!... the Akatsuki was an ally of the Kirigakure! researches proves that Tobi is the village's secret leader... for me, i don't really think Tobi is who he claims to be! what do you think?
I think Tobi is an apprentice or possibly the
brother of Madara. Hes Uchiha as he states in
chapter 309 where he fights Konan. Madara has
become more of an idea than an actual person. Tobi
represents the will of Madara. Also, when the real
Madara is resurrected he asks if the Moons Eye is
ready. That makes it pretty apparent that he had a
plan with Tobi. Honestly though, the fact is that
Tobi is the unfortunate soul thats going to get
owned by Naruto. The Naruto that is the true
reincarnation of the Sage of the Six Paths.
Chapter 572 makes that pretty apparent. Hes the
one all of the bijuu have been waiting to arrive,
the one the the Sage told them about and they
believe in him. Oh yea, its on like donkey kong.