im not sure how anyone hasnt noticed this yet but Madara/Tobi is really Madaras younger brother claiming to be Madara, for one look at the hair, and when Madara says to Kabuto that youve figured out my secret we knew right there that Madara wasnt the real Madara, so thats what lead me to believe he is actually the younger brother of the 2.

Anyone that proves me wrong will get the 10pts
or has a better theory