Quoting Powder119

It doesn't matter how Tobi acts around Itachi. Itachi would recognize his chakra with sharingan.

If it didn't matter and Itachi had recognized Tobi as fake Madara, we wouldn't be having this discussion and Itachi would have handled Tobi back then.

Itachi believed it was Madara, and Itachi's not a fool. Why would he confront him so boldly? That's not his style, nor would it be prudent, considering Madara's reputation.

Clearly, Itachi wanted Madara dead (implantation of amaterasu into Sasuke) if he tried to get close to Sasuke, but Itachi isn't the type to take the initiative against someone. Even in battle, he rarely makes the first move. When that "someone" is considered to be "immortal," as Itachi put it, how wise would it be to confront him directly?

I thought Shisui's body was found drowned in a river. At least that's what the Uchiha police investigators told Itachi in Sasuke's flashback. And of course, Shisui is made implausible by the age factor, which has already been discussed here. So the only plausible candidates, in my opinion, are Izuna or Madara's clone. People have also mentioned Kagami, though we know virtually nothing about that man except that he was Danzo's teammate. It seems that the man behind the mask is indeed an Uchiha. Some have pointed out that Tobi keeps his sharingan active all the time just like Kakashi. But Itachi had his sharingan active most of the time as well. We dont know for certain if Tobi's sharingan is active ALL the time, and if it is it could well be voluntary.

Now the very fact that Tobi knows so much about Konoha and the Uchiha seems to suggest that Tobi is indeed an Uchiha or at least from Konoha. He even knows the contents of the secret stone tablet of the Uchiha. Now while Kabuto and Orochimaru did brilliant research and espionage, there's strong indication that they never accessed the Uchiha tablets. They knew about it indirectly but were still unaware of it's contents. While on the other hand Tobi knows the contents very well. Only an Uchiha could have safely accessed those tablets. So it seems that Tobi is an Uchiha indeed

Besides does anyone know when exactly did Kisame become a member of the Seven Swordsmen of the Mist? I mean how long ago was that? When he killed the original owner of Samehada and was introduced to Tobi/Madara? We all know that the Fourth Mizukage, Yagura, was one among the only four ever to fully control a tailed beast (the others being Hashirama, Madara and Bee). Someone who has such a control over it's bijuu is expected to be far less vulnerable to genjutsu than even the best of shinobi, due to the mastery over chakra flow (the key to any genjutsu). And yet, Yagura was completely under the control of Madara/Tobi. I have a vague suspicion that Madara was alive during Kisame's time, because a normal sharingan that Tobi seems to be using couldn't have cast such a powerful genjutsu. I think such a powerful genjutsu would require at least an MS (Shisui's eyes being an exception). And we dont know if Tobi has an MS. He may, he may not.

Itachi is indeed a genius shinobi, no doubt about it. But how would it be wiser to confront someone who's primary motives is to ruin everything he have worked and sacrificed for if he is already dead. Clearly, he didn't planned to be resurected and fight for Konoha in an immortal state. You wouldn't want to plan everything and do all the precautions and then die having known that someone is there to ruin all the work. It's like watching a woman undressed infront of you and plan all your work at your head and do nothing

IM TOBI UNDER THE MASK. C:<

@oro-moro: I have had the same thoughts about the Mizukage. But about Shisui, they found his suicide note, but his body was unaccounted for. There could be some discrepancies in how the story was originally told ( I'm not sure of this though). That is why Kabuto could not find any DNA from him and as you can see he is pretty good at that stuff.

When the masked guy attacked the village, kakashi was very young then and obito would have been same age. He was too young to be masked guy. I don't think it can be shisui because danzo took his right eye and shisui gave his left eye to itachi. Uchiha izuna gave both his eyes to madara to awaken eternal sharingan. The masked guy has right eye intact. He uses it for teleportation, and only transplants his left eye for instance for the rinnegan. His right eye is his original eye. So uchiha izuna and shisui not likely to be the masked guy. Uchiha kagami is unknown but his age fits the description.

The masked guy use teleportation techniques far surpass fourth hokage and second hokage. He can use Izanagi because he has both powers of uchiha and senju. Right now he is welding the rinnegan and he can use it too. Considering all this Madara is still the masked guy or Atleast his body or powers. (someone else possessing him or madara posessing someone else) He probably doesn't want to reveal his face b/c it might reveal his secret to his survival or 'weakness'.

The most obvious person it can be IS Obito.
Here are the reasons why:
1: Kakashi's eye (from Obito) can force matter into other dimension simply by looking at them.
2: Tobi's good eye was supposively crushed by boulder when it could've just as easy awakened his power when forced and just phased through that side of his body.
3: Tobi is just Obito rearranged
4: The reason as to why Obito would be older at the time when he fought the fourth is because he can phase through to different dimensions. These dimension have no relativity of time and space. Therefore he can age many years in one of these places and it would only seem like moments or days for others.

I believe he was forced into one of these dimensions for so long, without knowing how to get out, that he developed his mentality on how to control the world.

Qraq as i said on the other blog ur wrong....... Obito's good eye may have survived as u say but he didnt have a left eye anymore and TObi had his left eye and used it to use izanigi against konan. second Tobi is not Obito rearranged lets count TOBI 4 letters OBITO 5 yea not a rearrangement by logical standards. 3rd ur whole aging theory is stupid bc if he is traveling thru dimensions with no relative time or space he wudnt age at all meaning he wud still b a kid bc no time and space means tht time doesnt not pass in any manner.