Board Thread:Theories and Speculation/@comment-26889573-20151008053113/@comment-27087341-20151017173854

The rinnesharingan is Kaguya's power born from when she assimilated the shinju. Kaguya and the Shinju bonding created the rinnesharingan. I think spiritual power is manifested from your deepest desire. Kaguya needed a form of control over humans so with the power of the shinju she awoken the rinnesharingan. U need both Kaguya and the shinju to create the rinnesharingan. I believe even the Sage said it was his mother's power. Just speculation tho.