Board Thread:Naruto Discussions/@comment-3279282-20140421103228/@comment-26302001-20140421180419

Kaguya had the same eye as Sasuke, she apparently had that eye as a Sharingan first, which turned into a mangekyo, then into that eye. I think that tomoe rinnegan is THE pinnacle of Sharingan power, and it is Rinnegan + Sharingan combined into one eye jutsu.