Thoughts on the Coffin
People have been misinterpreting Tobi's reaction to the sixth coffin for a long time now. Tobi was never afraid of it. It was never about the sixth coffin being able to overpower Tobi. Instead, Tobi was both repulsed and surprised that Kabuto was capable of summoning the sixth coffin and the power it held over Tobi was not strength, but information.
Theory 1 (Revise)
Tobi isn't Madara, but someone who idolized Madara. Think about it who can hate the Senju clan and Konoha more than Madara and would kill all the Uchiha, someone who was close to Madara and idolized him, or maybe a son or someone close, who was thinking Uchiha was traitors and hated Senju and Leaf for death of Madara. Sasuke now idolizes Itachi who he hated so maybe it is the same situation. Tobi knows everything about Madara, so maybe he saw when the real Madara gave Nagato the Rinnegan, and he used his chance. And as Tobi has Sharingan he is an Uchiha, Zetsu never called Tobi Madara, and he is the closest to him. So as of right now Tobi is impersonated Madara after his death, maybe he is Madara's son or related, because related and family people hate all people who are connected to their beloved and idols, and that is common for Uchiha that kind of hate. For all we know maybe Tobi isn't Uchiha because if he could have easily transplanted the Rinnegan into his eye, so it is possible that he also transplanted Sharingan.
So my theory breaks down into like this
Who is the man behind the mask?
Madara’s son (if he has one)
Madara’s brother = Izuna Uchiha
Someone close to Madara = Kagami for example.
Or way out there but possibly the Sage’s younger son; due to having an extremely long life, and it isn’t that either son had much of a reputation.
(I’m thinking outside the box here)
Or by some way the man behind the mask is actually somehow convoluted or intertwined with the real Madara, maybe the white Zetsu contains some sort of mystic powers that hold some of Madara’s sinister charka. (A Madara clone of some sort perhaps, that was able to split his soul)
Theory 2
Tobi may be part of the real Madara that somehow managed to split his soul. The Tobi that we are seeing now may just be a Hashirama's Living Clone with a consciousness. He may have split off from the `dead’ Madara to say alive longer. I have a lot of thoughts on how this split `occurred’. My most recently being that Madara may have fought Muu at some point, and copied his splitting technique to split himself at some point. - then one half got killed while the other continued to live and age with half of his original power. Another thought on the “split theory” is that Edo Madara just mentioned Nagato and thought Nagato revived him before he realized what is going on. Tobi mentioned wanting Nagato to do just that. It is plausible that Tobi wanted Nagato use Samsara of Heavenly Life Technique jutsu on himself to combine both of the “Madara’s” “making him complete. Are they, perhaps, still connected in a way? After all, Tobi mentioned before that he wanted Nagato to use the Rinne Tensei for him, and now Madara was actually expecting that Nagato had revived him. Or maybe Tobi is ticked off because Kabuto has control over potentially the strongest ninja out there in the war under his control. Perhaps that is why he called Kabuto a mad man because that wasn't the form of revival he had in plan for Madara's soul. Are they split somehow? Is Tobi not as human as we thought? Although "Edo Madara" and the "Tobi" are completely different people and of completely different chakra. Now if you guys had noticed, Ao mentioned that a NEW presence has arrived alongside Mu. Ao should recognize the “Tobi” chakra signature so he sensed that this new presence has a different chakra signature. In any case it seems that “Tobi” and “Edo Madara” know each other based their knowledge of Nagato. How do I know? Because of Madara's words, "So it FINALLY happened. Looks like that little brat Nagato was able to grow." This means that Tobi and Madara MADE this plan together.
OR
If Madara had died during the epic battle, he wouldn't know Nagato. It is possible that Tobi killed Madara, stole his identity, and continued operating to revive the Juubi. Madara thought he was revived by Nagato's Rinnegan Tensei and so he was surprised to find out it is Edo Tensei. I don't think Kishi would just have us believe that Tobi managed to fool Itachi, Jiraiya, Minato, Nagato, and Konan into thinking he was alive. Not to mention, I doubt he'd have said all of that stuff to Konan, whom he was about to kill, if he wasn't him.
So what are your thoughts on this?
