So, we all now know Tobi can not be MANDARA, not even an atom of MANDARA. And kabuto didn't pimp this MANDARA, all we can say is he backed-aged him. If Pain's eyes were use to pimp MANDARA, Tobi wont have any left, because MANDARA have 2 reningan not one.
Tobi should be someone like Kabuto/Oruchimaru. They are the ones who know alot and gather techniques.
Kabuto is still asleep, I bet he will only wake up when he understands himself and that should stop the loop.
Also, Tobi and Oruchimaru never crossed path. Am not saying they are the same person but the twist with Zetsu who we know definitely should be an experiment or sh*t like.
Oru fix Danzo, Yamato, Onko. (WAIT! Oru fix Danzo) so he definitely knows his way around the Sharingan.
Yeah,yeah Tobi talks about Oruchimaru with disgust, but he protects Sasuke like his own. Could it be that he wants Sasuke too.
Anyway, I think the one who knows everything is Tobi. Let's face the truth,he knows everything. Since the sage of the 6 path to Itachi's curse.
Check this out, MANDARA deals with the Nine tails, Tobi deals with the ten tails. Different people, different goals.