Rinnegan

The is the most revered and powerful of all the three great dōjutsu. It also seems to be by far the most rarely occuring of the three, as there have been only two known Rinnegan users. This theory is supported somewhat by Jiraiya's shock upon discovering that Nagato possessed the Rinnegan; the combination of its immense power and its rarity seems to have convinced many that the Rinnegan existed only in legend. It has also been suggested (though never confirmed) that both the Sharingan and Byakugan were somehow originally derived from the Rinnegan. The Rinnegan is characterized by a ripple-like pattern around the pupil. In addition to enabling an individual to quickly master various jutsu, the user may also use all forms of chakra nature manipulation, as well as the sixth "Yin-Yang" type of nature chakra about which little is known. Like the Sharingan and Byakugan, the Rinnegan also allows the user to see chakra, including an otherwise hidden barrier. The Rinnegan was first possessed by the Sage of the Six Paths, the founder of the ninja world and creator of the first ninjutsu. The only current known possessor of the Rinnegan is Nagato and his Six Paths of Pain.

Because the Six Paths of Pain are all reanimated corpses, their Rinnegan was added to their bodies by Nagato through some unknown means. By doing so, Nagato can see each individual body's field of vision, allowing the bodies to coordinate with extremely precise planning. Unlike the Byakugan, the Rinnegan has no blind spot. Because of this advantage, one must be blinded in order for a blind spot to be opened. The animals summoned by the Animal path also have Rinnegan eyes, suggesting that Nagato controls them as well. The fact that Nagato's Rinnegan seems to be constantly active would also suggest that merely keeping it active does not have the same draining effect on the user's chakra as the Sharingan does.

Trivia

 * Rinne (輪廻) 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.
 * Contrast to the anime depiction of it being multi-colored, the manga has shown that the Rinnengan actually is grayish purple in color. This mistake was most likely done due to the manga not releasing the color in time for the anime. This error was corrected as of episode 80 of Shippūden.