Alright, so due to immense reading on Narutopedia, I came to the fact that Tobi really is Izuna, and I would be glad to share the story to all of you.

After reading some articles, I came to know that Tobi's real identity is Izuna Uchiha. You might be thinking that this is impossible as Izuna is already dead. This is true, he HAD died a long time ago but he had lived again. How? Do you know how the real Madara died? No. This is how he died: Madara said that he had died shortly after getting the Rinnegan. He also stated that he was into the Eye of the Moon plan. Realizing that he was too old to live, he used his Rinnegan to revive Izuna (the same thing Nagato did to revive Konoha shinobi who have died) at the cost of his own life. Madara died, but not before giving his Rinnegan to Izuna, who in turn gave them to Nagato. He took Hashirama's DNA from Madara, then took two new Sharingans, one from Obito, and another from an unknown person. And so Izuna lived to fullfil Madara's plan of the Eye of the Moon.

So there you go, everything you need to know about Tobi. This is real, and should be accepted by everyone. If you dont believe me, then go to naruto.wikia.com and read the article on Tobi. Read it and sum them all up. Thank you for reading and tell me what you think of it.