Rinnegan

The is the most revered and powerful of all the three great dōjutsu. The Rinnegan is characterized by a ripple-like pattern around the pupil. In addition to allowing an individual to quickly master various jutsu, the user may also use all basic forms of nature manipulation. Like the Sharingan and Byakugan, the Rinnegan also allows the user to see chakra, including an otherwise hidden barrier. It was first possessed by the Sage of the Six Paths, said to be the founder of the ninja world and the creator of the first ninjutsu. The only current known possessor of the Rinnegan are 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. 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.

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.