Six Paths Technique

The is the origin of the unique techniques bestowed by the Rinnegan. In total there are actually seven of these paths that grant the user powerful and near god-like abilities:
 * The, which allows one to manipulate both attractive and repulsive forces.
 * The, which grants the user mechanised limbs, weaponry and armour.
 * The, which gives the ability to remove a soul and so, read a person's mind.
 * The, which lets the user summon a wide variety of creatures.
 * The, which can absorb all forms of chakra, including most ninjutsu.
 * The, through which one can summon and control the King of Hell.
 * The, which rules over both life and death.

These were all originally abilities that were used by one person, but because Nagato was crippled early on in his lifetime, he would go on to create the Six Paths of Pain technique where he used corpses and channelling the first six of the aforementioned abilities through each one, in order to compensate for his physical limitations. However, while the strength and speed of the techniques are greater than when corpses are used, and multiple Paths can be used at the same time from one body, the range of the vision granted by the Rinnegan is lowered quite a bit, not to mention that the safety of the main body is at greater risk.

Influences
Based upon the six Buddhist Paths of Reincarnation, each body was named after one of the different "Paths": Deva, Asura, Human, Animal, Preta, and Naraka. Each of these Paths, or realms, represents one of the realms a being is reborn into after death, determined by the accumulated karma of their past lives. While the two lower Paths, Preta and Naraka, are hellish, and the two higher Paths, Deva and Asura, are heavenly, all six are considered to be Paths of suffering because they perpetuate the cycle of Reincarnation; the only way to break it and ascend to a higher state of existence is to attain enlightenment.

Trivia

 * In Naruto Shippūden: Shinobi Rumble a technique called "Six Paths Technique" is used by Pain's Six Paths of Pain. In this variant, Pain generates a moderately sized sphere of debris overhead, then thrusts his arms downward, sending it crashing into the ground like a meteor. An enhanced, "Full Throttle" version of the technique called can also be performed.