Board Thread:Theories and Speculation/@comment-25547449-20160805204709/@comment-25547449-20160806021402

BeyondRed wrote: I think this theory is probably correct. It was never really explained what exactly is needed for the Ten-Tails to turn back into Kaguya, but we know Black Zetsu initiated the process and a massive amount of chakra was required. Kaguya probably wouldn't have turned into Ten-Tails in the first place if she wouldn't be able to turn back, so her chakra being spread around the world would go a long way to explain why she couldn't just turn back the instant Obito revived Ten-Tails and it fully matured.

I really hate how the anime messed up the Kaguya/Ten-Tails stuff so badly, because now we'll probably never know why she bothered turning into a rampaging monster in the first place. Maybe i'm wrong but kaguya didn't seem to gain conscious until the shinju was cut down. The shinju(Kaguya) was talking to madara, right?

The juubi is practically kaguya's own bijuu mode, so it'd grant similar benefits.