Board Thread:Naruto Discussions/@comment-3232093-20140617193601/@comment-28861328-20140818185635

Legendary Super Saiya-Jin 4 wrote: Ten Tailed Fox wrote: I'm not getting into a pissing match with you about facts you won't accept. Kabuto (stating that through his and Orochimaru's research) said that the Sharingan evolves into the Rinnegan. That's just a fact. Yes, but Kabuto and Orochimaru did not know about the whole Asura and Indra thing. So they didn't know that you need to combine both halves of Hagoromo's chakra to recreate his chakra to awaken the Rinnegan, which is the original form of Sharingan.

No, but they knew that the chakra of Hashirama and Madara needed to be combined to create the Rinnegan, which wasn't far off because Hashirama and Madara were the current transmigrants. Regardless, that wouldn't affect the fact that Kabuto called the Rinnegan a "natural progression" of the Sharingan. This with the new suggestion that the Sage actually "awakened" the Rinnegan, rather than having been born with it, suggests that he in fact had a Sharingan, but, like Ultimate said, since his chakra allows the Rinnegan to be awakened, his Sharingan was able to "[naturally] progress" into the Rinnegan, whereas future generations would need his chakra (through Asura and Indra's chakras) to accomplish the same with their Sharingan.