Tobi/Madara told us apparently he "gave" Nagato the rinnegan.
So is he talking crap again?
or is he telling the truth?
Also another thing to think about, kishi does like to put a spin on words especially with any dialogue with regards to tobi, kishi does this a lot in general anyway.
Maybe Tobi simply meant he talked to Nagato about his "no such thing as hope" philosophy during the time of Akatsuki beginnings and that helped him get Nagato and the rinnegan on his side which makes him feel he has ownership of both Nagato and the rinnegan.
Also apparently Tobi influenced Yahiko to start Akatsuki.
If he actually meant he somehow did something do Nagato to give Nagato the Rinnegan, were only aware of physical eye transplants like the cases we have seen with the sharingan and Byukgan. So this does offer some interesting theroies as to who the man under the mask is. I doubt there would be many in the history of the Naruto world that would understand how the rinnegan really works.
Also worth mentioning, during the kage summit the fifth mizikage assumed Tobi got Nagato to read the whole tablet in the Uchiha hideout to get all the info about the juubi and the So6P, this may go out the window now and the identity of Tobi is very important to understand what the hell is going on in the series so far. I also would imagine the mysterious 6th coffin would be telling evidence of who tobi really is too.
Also when Jiraiya fought Nagato he baffled by how the six pains had a rinnegan even the summons too. Oringinally I though this was because Nagato was sending his chakra to the bodies wirelessly and that's why hey had Nagato's powers. This could have something to do with the recent connection revealed with Madara and rinnegan.
Lots of questions, very few answers.
Here's my theory on the matter.
Personally and please excuse the language, I believe Tobi is talking **** about giving the Rinnegan in the literal sense. Nagato was blessed with the Rinnegan where the darkness is Madara which was speculated by Minato during his fight agsinst Madara, that Madara is the great darkness Jiraiya's prophecy spoke of. I believe this what Madara meant by "I gave Nagato the Rinnegan". Also Madara's chakra is more sinster than the fox(fox said this) and the fox is from the jubbi, that should tell you alot in itself
Keep in mind dispite Nagato working with Madara till the end of his life, Nagato and Madara had entiley different goals to achieve peace and using the word peace with Madara's plans should be used loosely more like control. Nagato wanted to provide the world fear to not enter any conflicts with his atom bomb scale jutsu, very simular to how nuclear powers work as deterrents of today. Each side would fear the mass annihilation if someone decided to attack. It does work in reality, clear example of this is the cold war and even now.
Also the Great prophency frog labelled Nagato and Naruto has the distined children when his vision ended just before Nagato died to combat the great darkness being Madara.
Also we actually saw Nagato awaken his Rinnegan when his parents died, so Madara is leaving alot out if there more to Nagato rineegan than meets the eye (lol).
NOTE: RINNEGAN NOT A BLOODLINE LIMIT