He was givin Madara'sRinnegan because of Madara's death, putting Rinnegan in the hands of an Uzumaki is enough to use Samsara Outer Path Resurrection.
This is why Madara gave it to Nagato. Also he was said to be used to synchronize with the Gedo Mazo for the "Eye of Moon" plan.
Nagato and the Akatsuki was just stepping stones for Tobi and Madara to finish there plans, and giving Nagato Rinnegan was one of them.
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Also notice what Era Nagato lived as an boy, during the 2nd Ninja War. Hiruzen was shortly Hokage here after Tobirama died, meaning Hashirama or better Uchiha Madara could still be alive during that time.
Come to think about the whole transplanting thing (which obviously happened), I doubt that Madara transplanted the Rinnegan into Nagato.
We know that Madara had been experimenting with Senju dna, but when edo Madara appeared he seemed surprised to find Hashirama stuck to his chest. This makes me believe that Madara was never succesful in merging with Senju dna.
In fact I believe Madara was dying from these experiments and as a last ditch resort gave up his eyes for them to be transplanted in a boy with remarkably strong Senju DNA.
I actually think that Nagato DID awaken the Rinnegan as he had the EMS transplanted and a severe trauma in combination with the Uzumaki DNA triggered the evolve (just like how the regular sharingan evolves by trauma).
The entire life of Nagato was followed by Tobi with the intention of one day returning Madara to life (or at least that was the original intent) and transferring his eyes back. The only problem that remained was combining both DNA's in Madara without him dying.
The leader i take it you are trolling?. Anyway the manga has made it very clear that nagato's rennigan was transplanted. He didnt activate it. First of all there is no such thing as activating the rinnegan to begin with, its a step from the sharingan therefore in order to activate the rennigan you must first have the sharingan and go up the stages;
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First of all nagato didnt activate the rennigan, it was given to him by madara. How do i know this. Firstly Tobi speaking as madara said it here;
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He speaking as madara prior to his fight with konan said that nagato was supposed to use rin tensei for him;
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So basically tobi talking as madara said that he gave nagato the rennigan, but also nagato was supposed to use rin tensei for him.
Now madara has clarified what tobi says. When madara first came out,the first person's name he said was nagato. He then said that it would appear that nagato had grown. This speak volumes. Madara gave nagato the rennigan, so that nagato would revive him later on, and thats exactly what tobi has said;
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Secondly how do i know that nagato's rennigan is transplanted. Well firstly because nagato didnt activate the rennigan. When nagato was a child, his hair had always covered his eyes. We never got to see his eyes, until when he beat that rock chunnin, during his training with jiraiya, did we see that he had the rennigan. He always had the rennigan, but didnt show it until the rock chunnin scenario.
Also the rule with implanted dojutsu is still consistent if the member isnt an uchiha. For example, have you ever seen nagato turn off the rennigan?. Have you ever seen nagato do this;
Sharingan;
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Ems;
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Rennigan;
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The fact that nagato cannot revert back and fort from the rennigan should tell you that it was transplanted. It a doujutsu has been transplanted and at the moment its transplanted it had the rennigan activated, thats the eye that would be transplanted and remain. No different to how the sharigan was at the time of transplant was activated therefore, thats what the receiver of the eye gets. This is constant with kakashi. At the time of of his transplant obito's eye was the sharigan therefore thats what remained consistent and kakashi cannot deactivate the sharigan no different to how nagato cannot deactivate the rennigan.
The next issue is why did madara give nagato the rennigan and i believe the kakashi and danzo scenario says it all. We know that if a non uchiha gains their eyes, because they do not have the body if they allow the sharigan to remain viisble it completely drains their chakra and thats why both kakashi and danzo have their sharigan eyes covered, to reduce the chakra drained.
Nagato on the underhand doesnt seem to have this problem because he is an uzumaki. Nagato has the powerful chakra that you could say rivals an uchiha for his rennigan eye to stay constant and not drain his chakra like kakashi and danzo who cover their sharigan. Basically here. Kushina's powerful chakra;
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Nagato's powerful chakra;
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Thats what im saying. Madara gave the rennigan to someone with powerful chakra, because that is what is needed for such a doujutsu like the rennigan. If kakashi had the rennigan, id guarantee he'd run out of chakra in a minute xd.
Also note that madara has also been said to have very powerful chakra, even for uchiha standards;
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This was first said by kurama, who also compared sasuke's chakra to madara's;
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So basically madara gave nagato the rennigan because nagato like himself (madara), had powerful chakra, chakra powerful enough to withstand the rennigan
+REP dude, U did the job for me, I wanted to write something like that to prove it to that stupid man that Uzumaki can't unlock Rinnegan and that you first need to go beyond EMS. So yes, very well done, thanks
With the rampant multi-posting, mini-flame wars, completely off-topic religious posts, in addition to the overall negativity and lack of respect for your fellow members, I think this topic has been discussed more than necessary.