Hagoromo Ōtsutsuki

, known to the world at large as the, was a legendary god-like figure who founded the arts of ninjutsu and created the ninja world. He was the son of Princess Kaguya Ōtsutsuki‎‎ and the first human to be born with chakra. He defeated the Ten-Tails in battle and sealed the beast within his own body, thus becoming the very first jinchūriki in history.

Background
Hagoromo was born to Kaguya Ōtsutsuki‎‎, a princess who ate the forbidden fruit of the Shinju that appeared once a millennium in an effort to gain god-like abilities to put an end to the constant wars during that era. As a result, Hagoromo was born with the ability to manipulate the same type of powerful chakra like his mother. The Shinju, furious with Kaguya's actions, was determined to get its chakra back, which caused the tree to assume a monstrous form of what many christened as the Ten-Tails.

The Ten-Tails rampaged throughout the lands until Hagoromo managed to single-handedly defeat the beast by becoming its jinchūriki, and became revered as a god for the virtue of his victory. According to Jiraiya, with his knowledge of the concept of chakra, the Sage travelled across the land, spreading his ideals and religion, the, which eventually came to be known as ninjutsu. His great deeds and ultimate desire to bring peace to the war-torn world made him widely known as the.

However, knowing that his death would unleash the Ten-Tails back into the world to continue its rampage and reclaim the chakra that mankind now possesses, Hagoromo separated the monster's chakra from its body before using before using Chibaku Tensei to seal the husk in what would become the moon. From there, he used his Creation of All Things ability to divide the chakra into nine fragments that are each given a physical form and name. Some time after their creation, the young tailed beasts were told that they were all still linked to one another despite being separate entities. Hagoromo also told them that would eventually become one again, yet not as they originally were, and that one shall appear at that time to show them what true power is.

Hagoromo would leave behind a tablet for his descendants, detailing the history of his struggle with the Ten-Tails. Only those who possess the Rinnegan can fully decipher the contents of the tablet, while a reader with a lesser dōjutsu can still partially interpret the information.

Hagoromo's ultimate wish was to establish peace across the world, but it was a goal that would never be achieved in a single lifetime. Knowing this, he chose to entrust his strength, dream, and legacy to his two sons. The older son, who inherited his "eyes" (his powerful chakra and spiritual energy), believed that power was the true key to peace. The younger son, who inherited his "body" (his powerful life force and physical energy), believed that love was the true key to peace. On his deathbed, Hagoromo chose his younger son to be his successor. Overcome by bitterness and envy, the older son fought against his brother, beginning a war between them. Their feud has continued on through their descendants: the Senju clan and the Uchiha clan.

Personality
The Sage of the Six Paths was a man who sought peace by spreading his wisdom across the world. He was exceptionally wise, as he was able to bring about a great change to the world by simply disseminating the principles of chakra and his religion. He also seemed to care a great deal for the tailed beasts when they were still with him; he gave them each a name as a sign of their individuality, and told them that no matter how far apart they grew, they would always be together, and would someday be led down the right path. In return, the tailed beasts showed respect and adoration for the Sage. Kurama even shed a tear at the thought of his imminent passing, suggesting that the beasts might even have viewed him as a sort of father-figure.

Appearance
Although initially depicted as a silhouette, several details about the Sage's appearance can be inferred. He had a small and trim goatee and short light-coloured hair that spiked up in the front with two distinctive pieces of hair resembling horns. He wore a white full-length cloak (haori) with a high collar, revealing his necklace with six red magatama. These symbols were later mimicked by Nagato's Deva Path, and the seal around the neck of Naruto Uzumaki's and Minato Namikaze's Nine-Tails Chakra Modes and Tailed Beast Modes. On the back of his cloak was a reflection of a seal which had the Rinnegan with nine magatama (both red in the anime) in three rows beneath it, much like the seal which appeared on Obito Uchiha's back after he became the Ten-Tails' jinchūriki. In one appearance where his face was partially visible, he was in an elderly state.

Abilities
Though not a great deal is known about all the skills Hagoromo possessed, he is widely accepted to be the most powerful figure in history, having been the only person to defeat the Ten-Tails: a being that was revered as a god, causing the Sage himself to be seen as a god. The Sage was also revered as the man to first understand the very nature of chakra itself. This wisdom, combined with his kekkei genkai, the Rinnegan, allowed the Sage to create the first modern ninjutsu. With such powers at his disposal, the Sage obtained a great following, as men and women from across the world strove to learn from his teachings.

Jinchūriki Transformation
The Sage developed the first technique capable of sealing a tailed beast inside a human body, making himself the very first jinchūriki in history. Having the Ten-Tails great power contained within him, the Sage developed immeasurable power and chakra that far surpassed all others, allowing him to be renowned for possessing the Treasured Tools of the Sage of the Six Paths which are tools that require a vast reservoir of chakra which would quickly kill any normal human in order to be used. Even on his deathbed, the Sage was able to employ his Chibaku Tensei technique on a massive scale and use that chakra to create the moon to seal the body of the Ten-Tails within it, a clear testament to his incredible power.

Ninjutsu
The Sage is revered as one of the most legendary figures in the ninja world, powerful enough to create the moon on his deathbed, using Chibaku Tensei. He was also very versed in fūinjutsu, able to first seal the Ten-Tails into his own body, just to seal it into the moon when his life came to an end.

Yin–Yang Release
By using the Yin chakra, that comes from the spiritual energy, and the Yang chakra, that comes from the physical energy, he had the ability to create form from nothingness with a mere thought to bring it to life. The Sage created the nine tailed beasts from the Ten-Tails' chakra by using this ability.

Bukijutsu
The Sage was shown carrying two objects. One was what appeared to be a katana, implying that he was skilled in kenjutsu, whilst the other was a shakujō — a Buddhist ringed staff which is meant to be used in prayer.

Treasured Tools
The Sage wielded unique tools which became known as the Treasured Tools of the Sage of the Six Paths, each of which possess a unique and powerful ability. The five treasures are: the Bashōsen, Benihisago, Kōkinjō, Shichiseiken, and the Kohaku no Jōhei. By combining the Benihisago, Kōkinjō, and Shichiseiken, the Sage could capture the word soul of his victims, and then draw them into the gourd to seal them away. With the Bashōsen, he could generate any of the five basic elements. The Kohaku no Jōhei allowed him to seal anyone without the elaborate procedures used for the Benihisago.

Rinnegan
The Sage was believed to have been the only shinobi to have fully mastered the Rinnegan, and also learned to control all five types of nature chakra. As a wielder of the Rinnegan, the Sage also wielded all the abilities of the Six Paths Technique.

Legacy
It is impossible to overestimate the Sage's effect on the course of the ninja world's development. As the first true ninja, he created the ninja world, revolutionised it, and left it forever changed. As the Sage's disciples grew continuously greater in number, it led to the creation of ninja clans, and later, ninja villages.

As time passed, the Sage ultimately faded into legend. His bloodline was divided into the descendants of his two children, which would eventually form the Senju clan — and through distant relations the Uzumaki clan — and the Uchiha clan. As a result of Madara Uchiha acquiring and integrating Senju DNA into his body, the Rinnegan would later resurface. Though he noted nothing happened initially after the DNA integration, when he neared the end of his natural lifespan, the dōjutsu finally awakened. With that, Madara Uchiha managed to undo the Sage's seal on the vessel of the Ten-Tails by summoning it from the moon and formulated the Eye of the Moon Plan to become the Ten-Tails' new jinchūriki.

Because Nagato, a pupil of Jiraiya's, manifested the Rinnegan, the latter suspected Nagato to be the reincarnation of the Sage himself. In reality, Madara secretly transplanted his own Rinnegan to the boy, without his knowledge. Nagato, as a descendant of the Senju-related Uzumaki clan, was the perfect host for the dōjutsu; however, Nagato noted that his own power would have paled in comparison to the Sage's. Others, including Kakashi Hatake, noted that the Rinnegan was viewed merely as a mutation. Kurama and Son Gokū's recognition of the Sage (and the tailed beasts' apparent status as the only survivors from the Sage's lifetime), lends credibility to his existence.

Before he died, the Sage told the young tailed beasts that someone would come and lead them on the right path. The tailed beasts would all later come to agree that this person is Naruto Uzumaki.

Trivia

 * The word means "feather mantle" and is a reference to The Tale of the Bamboo Cutter, in which Princess Kaguya is given a hagoromo to wear upon her return to the moon. The name  roughly means "big bamboo tree" and is derived from an obscure passage in the second volume of the Kojiki about the genealogies of Emperor Suinin, eleventh emperor of Japan, which states that he had a consort named, the daughter of a king named ; tradition holds that these individuals served as the basis for Princess Kaguya and the old bamboo cutter in the aforementioned tale.
 * The necklace that the Sage wore might be a reference to the Yasakani Jewel; a legendary magatama necklace that is part of the Japanese Imperial Regalia, together with the Kusanagi Sword and the Yata Mirror.
 * The Sage shares the same nickname with both the First and Third Hokage, who were all known as the.
 * Due to the Gold and Silver Brothers' ability to assimilate Kurama's chakra by eating some of its flesh, the Fourth Raikage suspected them to be distantly related to the Sage.
 * The horn-like tufts of Hagoromo's hair may in fact symbolize rabbit ears, representing his connection to the moon by evoking the moon rabbit; pop culture depictions of Princess Kaguya and the moonfolk often incorporate features like rabbit ears for this reason.

Quotes

 * (As quoted by Jiraiya)
 * (To the tailed beasts)