Tobi is really Obito
Obito didn't die
Madara died but came back to life and got really old because izanagi afterhours
Madara saved Obito after he was crushed and brainwashed him
Rin committed suicide because she was being manipulated by Madara
Madara was being manipulated by Black Zetsu
Black Zetsu is the son of the progenitor of chakra
The progenitor, Kaguya, is mad with power and hates everythibg with chakra in itclassic "that's mine," "everything belongs to me," etc.
Kakashi gets temporary Susanoo from dead Obito
Oh, yeah, and Obito not only resurrected the Ten-Tails, but became its jinchuuriki
Madara has a relief of the face of Hashirama (first hokage) jutting out of his chest because he bit off a chunk of him in the battle he died in and, after coming back to life, regurgitates and implants the flesh in his wounds
Sasuke gets the Rinnegan
Naruto is dead (momentarily)
Sasuke will be alive at the end of the series
Kakashi will be alive at the end of the series
Tenten, Choji, Lee, and everyone else you don't care about will be alive (with the exception of Neji, who is long dead)