The Modified ObiTobi Theory

When Tobi called himself Madara Uchiha, the theory changed to the belief that Madara's spirit was possessing Obito's body. It would explain Tobi's "split personality," where one minute he's a goofball and the next he's serious and evil. It is possible if you look at Orochimaru's jutsu.

Evidence for the theory
- The voices are different. When Tobi acts goofy there's a lot of emotion, where as, when his evil side speaks it's very deep.

- In addition to the evidence from the old ObiTobi theory, what Itachi says to Sasuke about Madara being a "shell" of his former self could mean he lost his Eternal Mangekyo Sharingan because he's using a new body.

- Tobi's Mangekyo ability is a time-space jutsu, which is similar to what Kakashi has. If each Mangekyo Sharingan user has to have a different kind then it would make sense that Tobi is really Madara using Obito's body because Kakashi's eye is Obito's eye.

- There's also the confrontation with the eight Konoha shinobi during their search for Sasuke. Right before he left, Even though Tobi was speaking to all of them, it seemed as if Tobi was looking directly at Kakashi, which is the moment when Kakashi sees the sharingan in the hole of the mask (volume 43 chapter 395 page 17 and page one of chapter 396).

- When Tobi removes part of his mask, we see a face that looks much more like an adult version of Obito than Madara (volume 43 chapter 397 pages 1-3).

(7/21/12) More hints have appeared in Chapter 594. Kakashi is about to make a move, saying: "I'd like to try something before it [Juubi] is revived, if possible," to which Tobi responds with: "Kakashi... you always open your mouth so easily. It's no wonder you've lived a life of regret." Kakashi seems surprised and Gai questions him on who he is. Tobi's reply to him is: "You don't remember faces so what's the point in telling you?" This is HUGE foreshadowing as it implies that whoever Tobi is, Kakashi and Gai know him.

- (8/1/12)
In Chapter 596 Kakashi thinks that his kunai is what scratched Tobi's mask. With the help of Gai and Naruto he tests his theory by using Kamui on Naruto's Rasengan, sending it into another dimension. Shortly after it fades away, Tobi's shoulder shows damage from it. This confirms Kakashi's theory, that Tobi is really using one justu and is going back and forth into the other dimension. It also implies that Tobi and Kakashi's jutsu share the same dimension.

Also, a Japanese Magazine called "+act" has translated bit of Kishimoto's notes on the new movie Road to Ninja, and according to them it says "Madara (Obito)." This does not 100% confirm the theory, but it makes it more possible now. Source (google it as well for more).

- NEW (8/29/12)
As of chapter 599, it is 100% confirmed that Tobi is Obito.

Problems with this Theory

The biggest problem with this theory is why would Madara choose to take over the crushed body of an Uchiha when he could have taken over the body of any of the healthy Uchiha back in Konoha? The answer I think is that he couldn't choose any other body. Maybe his host needed to be close to death or dead in order to possess a body.

Do I Support this Theory?

Yes. Why? because I don't think Madara, who'd be in his 90's if not 100's, would be able to move or fight the way he does.

This is My Version of the theory

Remember how Obito's last thoughts were that he wanted to spend more time with Kakashi and Rin? well I think that Madara's spirit may have tricked him into thinking that he'd get that chance if Obito allowed Madara's spirit to go into his body. Obito allows him to but Madara takes Obito over completely because Obito is weak. Madara maybe then had Obito kill Rin to get the Mangekyo Sharingan. It would explain why Kakashi got it, maybe it just took longer for Kakashi's to evolve or it needed intense training to activate it. When Madara summoned the Kyuubi to attack Konoha, he used up a lot of his energy and because of that Obito gained control again. But because of the guilt that he killed so many shinobi before and during the Kyuubi attack, including Rin and his sensei, he felt he couldn't face Konoha, especially not Kakashi. So he went with Zetsu (for some reason i can't really think of). Then when Deidara blew himself up it could have triggered Madara to surface again in order to stay alive. Now Madara is too strong for Obito to overcome. In the end I think the threat of Madara Killing Kakashi will give Obito the power to take control again.

Theory Update

As of chapter 559, Tobi cannot be Madara as the real Madara was just resurrected. Looks like I was right to second guess that Tobi was Madara. Although, the events of the current chapter have pretty much shot my personal theory down harshly (it can't be Madara's spirit controlling Obito's body).

Theory Status

False