Rinnegan

The Rinnegan is a dōjutsu said to be the most powerful of all. Its occurrence is so rare that many people once believed its existence was only a legend or a mutation.

The Rinnegan is characterized by a ripple-like pattern around the pupil, with a light purple iris and sclera. In addition to enabling the user to quickly master various jutsu, the user may also use all six forms of chakra nature transformation which, as noted by Ibiki Morino, literally allows its user to use any technique they wish, though it wasn't been noted if it does or doesn't give the user the ability to use the advanced nature types. It also allows the user to use all of the six paths techniques, a series of ninjutsu unique to the Rinnegan user. Like the Sharingan and the Byakugan, the Rinnegan also allows the user to see chakra, including otherwise hidden barriers. According to Nagato's partner Konan, the possessor of the Rinnegan can also control the seventh path of Pain, who is "beyond life and death", that can use the Outer Path: Samsara of Heavenly Life Technique, which allows the Rinnegan user to revive all people who have recently died.

Because Nagato's Six Paths of Pain were all reanimated corpses, their Rinnegan was added to their bodies by Nagato through some unknown means. By doing so, Nagato could see each individual body's field of vision, coordinating the bodies with extremely precise planning, even during battles. Due to this effect, unlike the Byakugan, the Rinnegan does not have a blind spot, as long as the bodies are looking in every direction or at least one body is looking at the desired target. Because of this advantage, an opponent must blind one body, or distract all others in order for a blind spot to be opened. The animals summoned by the Animal Path also possessed the Rinnegan, suggesting that Nagato controlled and could see through them as well. Madara Uchiha also stated that while the Sharingan and to a greater extent the Mangekyō Sharingan can translate some of the text on the tablet the Sage left behind, only the Rinnegan can fully read the words on it.

Madara claims that he gave Nagato the Rinnegan. For this reason, he believes he is entitled to taking the Rinnegan from Nagato's body after his death, and has recently put one of the Rinnegan eyes in his left socket, replacing the Sharingan he sacrificed to use Izanagi in his battle against Konan.

Trivia

 * In the anime, the Rinnegan is depicted as being multi-colored in its first few appearances. Once colored manga illustrations of the Rinnegan are released, this is corrected.
 * is the Japanese term for Samsara, the cycle of reincarnation or rebirth in several Indian religions. This is reflected in the names of Six paths of Pain, which share the names with Samsaric realms of reincarnation.
 * Upon the death of his parents, Nagato awakened the Rinnegan and used its powers to kill his parents' killers. In the manga, for some reason, it didn't remain active, as Nagato awakened it once more to defend Yahiko from an Iwagakure Chūnin. From that point on, his eyes are never seen without the Rinnegan design. However, in the anime, he temporarily awakens the Rinnegan again to protect Yahiko and Konan from an explosion.