ProdigyXItachi
Member
It is stated in the manga that Madara awakened the Rinnegan after his battle with the 1st and before his death. Therefore I believe that the Rinnegan is a natural evolution of the Sharingan. I think that some people are getting confused because edo Madara has Senju cells implanted in him from Hashirama. But that was done after he was dead (by Kabuto) and was ultimately applied to his edo tensei form. This seems to make sense to me.
As for how Negato received/awakened his rinnegan that seems to be a product of tobi/madara's doing. If he awakened it by himself naturally that would obviously put a kink in my theory. If that is the case then there would be evidence to support both Uchiha and Senju being able to naturally access rinnegan. Since this is currently unknown exactly how he achieved rinnegan I'm sticking with my theory. Either way, we know that Rinnegan is a natural evolution of the sharingan. For that matter it makes you wonder how the byakugan is related to the sharigan? Does the byakugan user evolve to a sharingan? It's strange how Kishi has largely left the Byakugan out!
As for how Negato received/awakened his rinnegan that seems to be a product of tobi/madara's doing. If he awakened it by himself naturally that would obviously put a kink in my theory. If that is the case then there would be evidence to support both Uchiha and Senju being able to naturally access rinnegan. Since this is currently unknown exactly how he achieved rinnegan I'm sticking with my theory. Either way, we know that Rinnegan is a natural evolution of the sharingan. For that matter it makes you wonder how the byakugan is related to the sharigan? Does the byakugan user evolve to a sharingan? It's strange how Kishi has largely left the Byakugan out!