Re: Rinagan comes from jubbi
There are some details that we don't know about here, and you're making some assumptions that might not turn out to be true. First, answer some questions (that haven't been answered explicitly in the manga):
Originally Posted by Shunsin no Shisui
1) Did the So6P have Rinnegan BEFORE he captured and sealed the Juubi?
2) How did Madara unlock the Rinnegan, and why did it wait until he was so old to unlock?
3) Why does the Juubi's eye look like a cross between a Rinnegan and a Sharingan? Did the Juubi's eye look like that BEFORE fighting the So6P?
4) Slightly related, we've seen the Gedo Mazo use techniques for pulling souls out of the body (as used against Hanzo/Danzo when Yahiko died, and used to extract the Bijuu from the Jinchuuriki). Does this power come from the Rinnegan originally, through Nagato and the chakra receiver rods?
We ASSUME that the So6P had the Rinnegan before fighting the Juubi. We ASSUME that the Juubi's eye looked the same both before and after the battle. We ASSUME that Madara unlocked the Rinnegan simply by having Hashirama's DNA and waiting in a cave for several years for it to activate. We ASSUME that the Gedo Mazo had no powers of it's own but was using soul-stealing techniques from Nagato's eyes. However, any of these assumptions might be wrong because the manga hasn't explicitly answered any of these things yet. If one of these things is wrong, our understanding of the Sharingan/Rinnegan/Juubi might be completely changed.