So, I think it's fair to say that Madara is the one who gave Nagato the Rinnengan, and that Nagato's eyes were originally Madara's (since decrepit Madara said, his Sharingan was not his own eye). Still want to know:
a) Why did Madara pick Nagato?
b) How could Madara know Nagato would use the Rinnengan for his sake-- considering Nagato had the eyes before he met Jiraiya, but it seemed like he was just an innocent kid when he met Jiraiya.
c) Why couldn't Nagato use the Sharingan or Mangekyo Sharingan? It's not like any other character, Uchiha or otherwise, had any trouble with rejection from the Sharingan or using the Sharingan's various forms. Fuck, Itachi gets a fucking bird to use the Sharingan. lol
More food for thought:
Edo Tensei-- how does it work?
Edo Tensei brings back a user's body (and basic clothing I guess).
I always figured Edo Tensei worked on DNA, since DNA is the foundation of the Kushiyose (you need a body part), and Edo Tensei also brings back body parts that aren't with the original corpse (Itachi's eyes). Also, Edo Tensei doesn't revive weapons like Sasori's puppets or the swords of the 7 Swordsmen of the Mist.
So... if Nagato's Rinnengan belonged to Madara originally, why was he revived with his Rinnengan? After all, it shouldn't be part of his DNA...
Then again, as we all know, DNA doesn't work like that anyway. Whatever Cell from Dragon Ball would have you think, cells/DNA don't store information from the brain, like knowledge, skills, experience-- they don't even store age/maturation info. When you clone from DNA, you get a baby with 0 experience/growth. If you cloned Itachi's DNA, never mind the developed Mangekyo Sharingan or even the Sharingan-- you should get nothing more but a baby.
So Edo Tensei working based on DNA is a bullshit premise to begin with. But if that's the case, why can Edo Tensei revive knowledge, body parts (eyes), and even clothes, but not weapons?
I'm so confused. lol
It's explained that the "soul" is revived using Edo Tensei, so I guess the soul provides the blue print of the body/mind/clothes... but not weapons? ah whatever, no use thinking about it too hard...