Board Thread:Wiki Discussions/@comment-24825578-20140416184222/@comment-3440052-20140417031954

Muvinco wrote: So... anyone have any theories about Sasuke's Rinnegan with tomoe in it?

My current theory is that the Rinnegan that we've seen thus far from the Sage, Madara, Obito, and Nagato is a diluted version of the Rinnegan and the result of the eye technique being passed on from the original wielder. That original wielder was the Sage's mother whose third eye was a product of the Shinju fruit, which is also the eye seen on the Ten-Tails (the guardian of the Shinju fruit).

My theory is that what Sasuke received is the 'companion eye' to the original one that Kaguya bore as her third eye.