The Rinnegan is an extremely powerful Kekkei Genkai in the world of Naruto. This eye is believed to be part of the Three Great Dojutsu, and comfortably the strongest among all three. It was revealed to the fans quite a long time after the Byakugan and the Sharingan, however, the wait was certainly worth it as this eye went on to be revealed to have godly powers. The Rinnegan is an exceptional eye that not just anyone can possess.
Hagoromo Otsutsuki, the Sage of Six Paths, was the first one to wield this eye in the Naruto story. Only by recreating his chakra can this eye be awakened. Thus, to gain this eye, one would need to combine the chakra of Indra and Asura. Those who passed the Rinnegan are known to be Gods and the power of this eye certainly is godly.
The Power Of The Six Paths
Just like all the other powerful eyes in the world of Naruto, the Rinnegan has some good ones and some extremely overpowered ones. Starting with the standard ones, this eye allows the user to see through invisible barriers, along with letting them see the chakra circulatory system, although not as well as the Sharingan or the Byakugan. It doesn't, however, let them see through any obstructions. While this power is nothing special, all the other abilities of the Rinnegan make it truly overpowered. For starters, just wielding this eye allows the user to master all the natural transformations. Being a master of all five natures a certainly an overpowered ability and the Rinnegan allows the user to master them to perfection. If that wasn't enough, the Rinnegan has its own set of abilities known as the Powers of the Six Paths.
Each path the Rinnegan is known to hold an overpowered ability, starting with the Animal Path, which allows the user to summon mighty animals that seemingly don't die. The Asura Path allows the user to make mechanical alterations to their body and use highly mechanized tools as well. The user can also absorb any form of chakra through the Preta Path, along with being able to summon the King of Hell through Naraka Path. Furthermore, the forces of attraction and repulsion can be controlled with the Deva Path and the souls of living beings can easily be extracted using the Human Path.
The Power Of The Outer Path
All the Six Paths Powers make the Rinnegan extremely overpowered. The user can easily devastate an entire country with ease and a small glimpse of that was given to the fans when Pain invaded Konoha. Just by using a portion of his powers, he was able to destroy the entire village. It must be kept in mind that Nagato was severely crippled by this point and despite that, he was able to destroy an entire village with ease and then go on to continue fighting Naruto. Furthermore, the Rinnegan did not even belong to Nagato. The true power of this eye can only be brought out by its original wielder, which just goes on to prove that it is godly and far surpasses the power of both the Sharingan and the Byakugan.
Perhaps the scariest power that the Rinnegan possesses is the Outer Path. This Path is what gives godly dominion to a user of this eye as it allows them to control life and death itself. Attaining immortality is possible using this Path and even reviving dead people is, in fact, possible. That certainly isn't all, as the Outer Path also allows the user to produce the black rods into which chakra can then be transmitted, making them a very powerful weapon. Furthermore, it lets the user bind Tailed Beasts with chains that have Cursed Seal embedded into them, and it also lets the user create six bodies to control, known as the Six Paths of Pain.
The Special Abilities
If all that wasn't enough, the Rinnegan also grants its users special abilities that are unique to them. Sasuke Uchiha, for example, has the power of Amenotejikara, which allows him to swap places over short distances with anything. This ability is unique to his Rinnegan alone. Similarly, other users of this power also have abilities unique to them. In the case of Madara's eyes, the ability of being able to use Limbo was observed. Limbo is a powerful jutsu that allowed Madara to summon clones of himself that were in an entirely different plane of existence.
They could only be seen or sensed with the powers of the Six Paths. The Rinnegan could help see them while the power of the Six Paths Senjutsu could sense them. Similarly, Momoshiki's eyes gave him the power to observe any form of chakra and then expel it through his other hand. Urashiki could manipulate time for a short while. All these powers, put together, make the Rinnegan an incredibly overpowered ability.