I am slightly starting to believe that Tobi may just be Obito. Only problem is it doesn't match up with the timeline. Tobi and Kakashi are close in age, Nagato and Konan are older than them, and Tobi claims to be the one who "gave" Nagato the rinnegan. Plus there is a slim chance he survived the accident he had.
But on the other hand Tobi was only using his right eye for a long period of time and Kakashi's sharingan is in his left side. Maybe that is just a coincidence though.
But on the other hand Tobi was only using his right eye for a long period of time and Kakashi's sharingan is in his left side. Maybe that is just a coincidence though.