I HAVE TOBI THEORY! I know we’re tired of these new theories  every single time we see this guy in a chapter but bare with me. When  Tobi said that he gave the Rinnegan to Nagato and that it all belong to  him it got me thinking. Where the hell did he get them from? So here’s  my theory maybe this guy is the Rikudo sage. The Rikudo sage is suppose  to have started the ninja and brought some kind of peace over the world  at one point. Maybe when he was getting old the world started to go into  chaos again and since he was dying he knew he couldn’t stop it and was  angry because his way of the ninja failed. It failed so much that his  own children turn against each other showing him they couldn’t be  entrusted to follow his in his footsteps. Feeling helpless and dying he  released the Juubi ( Did anyone else realize Juubi is Bijuu backwards?)   and split them up knowing he couldn’t trust the Juubi’s power and the  ninja world to either one of his sons. So to once again bring lasting  peace to the ninja world he needed to come up with a way to live again  forever, by transferring his soul into other ninja.
So before his own body died he transferred his soul into another ninja  and took his Rinnegan eyes and started his master plan. He couldn’t just  implant the Rinnegan into his new body because they were too powerful  for normal shinobi to possess, so he realized if he was going to bring  peace he needed power so he went to the next most powerful weapons his  children, Uchiha and Senju. After observing their power for years he  witnessed the power of Madara Uchiha and Hashirama Senju. He might have  been impressed with Madara which is why he chose to go after the  Sharingan believing it was the quickest way to gain power.
Realizing that Madara was one of the strongest ninja in the shinobi  world and admired his power he transferred his soul into Madara’s body  so he can use his eyes to their full potential. He then went to start  his plans to once again take control of the world, first by take over  Kirigakure and therefore being responsible for the BloodyMist Era.  Soon  after he realized that even he couldn’t use the Sharingan to the same  level as Madara which would interfere with his plans on using Madara’s  Sharingan to cast an Eternal Tsukuyomi on the world putting them under  his control so he can bring lasting peace. Also Madara Uchiha’s body was  starting to reject him so he needed to find another Uchiha. So one day  he came across the body of the almost dead Obito Uchiha and he  transferred his soul into Obito’s body also somehow repairing it and  since Kakashi had Obito’s eye and the other one was crushed he implanted  Madara Uchihas eyes which explains why he claims to have his power. In  the manga he says he’s not at full power, maybe he means his power as  the Rikudo Sage but even if he did mean Madara he may not was able to  use the Sharingan to the same level as Madara.
Realizing that the he will need the Eternal Mangekyou’s Sharingans  power to bring peace with his Moons Eye plan once again he went to find  another Uchiha with eyes with the same potential as Madara’s but this  time he would take this ninja under his wing and help him obtain EMS so  he could use the full power of the Eternal Mangekyou Sharingan, that’s  where he found Itachi Uchiha. Scared that one day another Uchiha would  be born with even stronger eyes capable of defeating him and breaking  his control over the world he had them eliminated. Also seeing his older  son, the creator of Uchiha, hatred throughout the clan he eliminated  them because he knew they would be a force of evil in the world which is  why he chose his younger son over him.
Also seeing that Itachi wouldn’t help him with his Moons Eye plan he  went after Sasuke who also had the stronger eyes. Now that he has Sasuke  with the EMS he has his eyes on Naruto because he is a descendant of  the Senju he needs his body to tranfer his soul into so he can finally  implant his Rinnegan which will be his rebirth and gain his full power  and use it to revive the Juubi and become the ultimate jinchuuriki and  with his power and Sasuke’s Sharingan bring the world under his control.
I’m guessing he figures since letting the world think for itself and  allowing them to evolve slowly on their own didn’t work so he is taking  it in his own hands once again and this time will force peace on the  entire ninja world. I also think this is what will make Naruto so great,  to be able to defeat the Sage of the Six paths and revolutionize the  ninja world. Naruto will remind him what he use to believe just like he  reminded Nagato. This is all just a theory so don’t go to hard on me.
 

 



