Board Thread:Theories and Speculation/@comment-1512913-20150221101637/@comment-1944809-20150223163828

This is what I believe:

I don't think that the Rinne Sharingan has Rinnengan powers. Kaguya doesn't use any Rinnengan powers, and while Sasuke thinks that the Mugen Tsukuyomi is a Rinnengan, he also thinks that the Rinnengan can also release the technique, which was partially wrong (the chackra of the Juubi/9 Bijuu is also required). So, the Rinne Sharingan is a much more powerful version of the Sharingan.

As for Sasuke's Rinnengan, I think Sasuke has an early stage of the Rinnengan, and his Rinnengan will eventually evolve to the Rinnengan Hagoromo & Madara had. If Sasuke has only one Rinnengan, doesn't it destroy Madara's point about the Sharingan's/Rinnengan's true power can only be achieved by having both eyes? Plus, Kishimoto hides Sasuke's right eye in the Epilogue era in all of his appearances in the manga or in artwork, so there has to be a reason, right?

We see Edo Madara being unable to use MS powers through the Rinnengan, but we also learn later that his Rinnengan in Edo Tensei form was an inferior fake that even lacked some powers (Summoning: Gedo Mazo & Rimbo: Hengoku). So, maybe Madara can use Sharingan & Mangekyo Sharingan powers through his real Rinnengan? I believe that he can.

My theory is that Kaguya had the Rinne Sharingan & Byakugan, but not Rinnengan & Tenseigan. Her sons had each of her powers, Hagoromo was born with the Sharingan (which is the Kekkei Genkai version of the Rinne Sharingan, which is a Kekkei Mora) & Hamura was born with the Byakugan, and they evolved evolved their eyes into brand new forms that their mother didn't have, the Rinnengan & the Tenseigan respectively.

As for how the Rinne Sharingan is obtained, it is shown that it's either obtained by eating the Chakra fruit (Kaguya got it like that), or by becoming the Juubi Jinchuriki + have both Rinnengan (Madara got it like that. I think Hagoromo awakened this eye as well, but he sealed it because he disliked its power (he called Mugen Tsukuyomi "a gruesome Jutsu").