Hagoromo Ōtsutsuki, known to the world at large as the Sage of the Six Paths, was a legendary god-like figure who founded ninshū and created the ninja world. He was the son of Princess Kaguya Ōtsutsuki and, along side his brother, were the first of humans to be born with chakra. He and his brother also defeated the Ten-Tails in battle, and sealed the powerful beast within Hagoromo, thus making him the first jinchūriki.
Hagoromo was born as one of two children 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, which she used 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 as 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 that would come to be known as the Ten-Tails.
The Ten-Tails rampaged throughout the lands until Hagoromo, with help from his brother, managed to defeat the beast by becoming its jinchūriki, causing him to be revered as a god for the virtue of his victory. With his knowledge of the concept of chakra, Hagoromo travelled across the land, giving chakra to others as well as spreading his ideals and religion, ninshū, which eventually became the ability known as ninjutsu. According to Jiraiya, his great deeds and ultimate desire to bring peace to the war-torn world made him widely known as the Saviour of this World.
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 dream and legacy to his two sons, and began to teach them ninshū. The older son, Indra, was acknowledged by Hagoromo as a true prodigy, who quickly began to revel in his natural prowess and became very solitary. The younger son, Asura, proved to be the exact opposite, having shown no special abilities or natural talent, but he pushed on through his limitations, growing stronger and more mature because of his struggles and making friends along the way. Hagoromo acknowledged Asura's chosen path, agreeing that love and cooperation were the true key to peace. Inspired by his younger son, Hagoromo separated the Ten-Tails' chakra within his body and used his Creation of All Things ability to divide it into nine separated bodies, creating the tailed beasts and giving each a name. As a result of extracting them all at once, Hagoromo was left weakened and incapacitated for several months, though the powerful life force of the Ten-Tails' husk kept him alive. 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 they 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 eventually used Chibaku Tensei to seal the husk of the Ten-Tails in what would become the moon. On his deathbed, he chose Asura to be his successor, but Indra, overcome by bitterness and envy, fought against his brother, beginning a war between them that would continue through their descendants.