Why that madara or the mask man said :"You probably know that i'm an uchiha and I hold a grudge towards the clan and the village"....its really obvious that he hate Konoha coz he hate so much Hashirama but why he also hate Uchiha?
The Uchiha didnt betray Madara, it was decided
before the fight between Madara and Hashirama that
the winner would unite the clans and lead them as
the Leaf Village. Madara lost and the Uchiha
united with the Senju as the lesser clan. To the
victor go the spoils. Madara is just so self
absorbed that he couldnt see the Leaf with anyone
other than him as the leader. I really dont think
hes pretending to be Madara. I think hes part of
Madara, left behind to revive Madara before the
Moons Eye Technique.
Tobi can also be Izuna. Izuna angry at the uchiha
clan for abandoning his brother, wanted revenge on
them. If tobi was izuna and he willingly gave his
eyes to madara, he would be angry, when sasuke
mentions to him how madara forcefully took his
eyes. If izuna loved his brother so much, he would
be have been emotional when told him the opposite
what happend to him.