Outer Path — Samsara of Heavenly Life Technique

By channelling his power through the King of Hell, the Rinnegan wielder can re-infuse new life force energy to the bodies of those who have died. With their rejuvenated bodies acting as an anchor, the individual souls are then able to leave even the crossroad between life and the afterlife, returning back to their physical vessels. The technique targets all the individuals killed, even those not necessarily killed by user. This technique seemingly requires a massive amount of chakra, as Konan feared the worst for Nagato when he used it after having previously expended so much chakra. Nagato also became severely weakened, his hair became increasingly thinner and greyer as he performed the technique.

Influences
As with many of Nagato's techniques, it is influenced by Buddhist terminology. , derived from the Sanskrit Tīrthika, refers to any doctrine which "treads the outer path" to enlightenment. This is opposed to the teachings of orthodox Buddhism, the, and is thus considered misguided and heretical.

Trivia

 * While Tobi noted to Zetsu that this technique was originally meant to be used for his purposes, but in reality it was supposed to be used to revive Madara Uchiha. As Zetsu was present when Madara for the planning of this revival, it is possible that Tobi had at one point decided to use this technique on himself should he need to and not resurrect Madara. Madara would have eventually reincarnated anyway and expressed surprise and disappointment that his return didn't go as planned.