Asura Ōtsutsuki

was the youngest son and heir of Hagoromo Ōtsutsuki as well as the ancestor of the Senju clan.

Background
As a child, Ashura lived in his brother's shadow in every conceivable way, having no natural talent. While constantly struggling to improve himself, Ashura matured emotionally as he made many friends and allies, eventually making his own talents blossom and finally catching up to his older brother, Indra. On his deathbed, Hagoromo selected Ashura to carry on his dreams of peace for the ninja world. Indra, believing he should have been chosen, fought him to try and claim what he felt he deserved. The descendants of the elder brother, who would become the Uchiha clan, would continue this fight with the younger brother's descendants, who would become the Senju clan.

Personality
Ashura believed that love was the ultimate key to peace, and loved his father greatly as well. Though the son of the famed Sage of the Six Paths, Ashura was born with practically no talent, but because of this, he learned the value of depending on and cooperating with others. Through sheer hard work and determination, he was able to awaken his own power. Because he never lost sight of the value in people, he would ultimately become the successor to his father's ninshū as Hagoromo wanted the world to adopt this way of thinking.

Appearance
Ashura had short, spiky hair, two locks of which were wrapped in bandages framing either side of his face in a similar manner to his brother. He also wore what seemed to be a forehead protector with markings on the sides but no symbol on the metal piece.

Abilities
As a child, Ashura was considered to be unskilled, much unlike his genius older brother, Indra. Over the years, through hard work and dedication, Ashura awakened the inherited power of his father's body, life force, and physical energy and ultimately obtained power equal to that of his brother. He also become a capable leader, obtaining countless loyal followers. It was this leadership that caused his father to make him the successor to ninshū. In battle, Ashura was seen encased in a two-headed, six-armed avatar wielding several dark-coloured spheres. He also wielded a shakujō as well as a sword on different occasions.

Legacy
According to Hagoromo, Ashura's chakra remained after his body was destroyed and he was eventually reincarnated into Naruto Uzumaki.

Trivia

 * As Ashura believed that love was the key to peace, it is possible that Hashirama Senju's "Will of Fire" evolved from his beliefs. Similarly, his brother's descendants rose to oppose this, inheriting the "Curse of Hatred".
 * Like his father, Ashura wielded a shakujō in battle. His choice of weapon could represent his desire for love and peace while his brother's choice of a sword could symbolise his lust for power.