Truth be told: Madara Uchiha is dead!
The Trump Card:
So it has come to pass that Kabuto's trump card, the coffin that he summoned we could not identify, have made its appearance in the war. Kabuto knew full well what he was doing when he joined to war with Madara. The hair is as it was when he fought Konoha Shodai. The crest on the back is Uchiha. The eyes that can truly identify him is present, standing next to Gaara. Oonik himself is amazed by his own eyes. Everything says its Uchiha Madara. If this is true, then the one that is calling himself Madara is not him at all. Is it possible that its his little brother. We didn't get any particular moments of the history where his hair, feathers, and clother was the same as the one set in the Valley Of The End.
This is too good to be true. Uchiha Madara is resurrected to the battle field.
WOW! WOW! WOW!
I never expected this would happened, only that the one calling himself Madara was an imposter.
My Theory:
I remember the days when many said that the man calling himself Marada was not him. We speculated for many months. Kishi even went to the lengths to make the readers believe that he is truly Madara. Who can this one calling himself Madara PEIN!
I believe that the story of Madara and his eternal Sharingan is false. He did take his brother's eyes, but he didn't watched his brother die. I believe that his brother lived, and was later implanted with another Sharingan. When Madara fought the Shodai, he died. His brother then took his whole in the revolution bent on revenge of this older brother. By making people believe that he was Madara, would make people think that he is immortal. The now broken body is do to age and experiments on his tainted quest to be immortal. When Kabuto resurrected the coffin in front of him, he was shocked, as DNA is needed to complete the jutsu.
Madara PEIN True Identity:
Its very likely that the now resurrected Madara Uchiha knows the identity of the one calling himself Madara PEIN. The possibility that Kabuto came about this information about his identity is high. Who truly is Madara PEIN?
P.S. Muu also recognized Madara Uchiha after the summoning