Asura Ōtsutsuki

was the younger son of Hagoromo Ōtsutsuki and heir to his teachings. He was also the ancestor of both the Senju, and the Uzumaki clans.

Background
In the anime, Asura's birth came with problems, which led to the untimely passing of his mother. Despite the passing of his mother, Asura's childhood was peaceful and joyous, spending his time either blissfully alongside his father and brother, or playing with the village children. When old enough, the two began studying Ninshū under their father in the hopes of one of them becoming the great sage's successor. As a child, Asura lived in the shadow of his genius older brother Indra. Having displayed no natural talent himself, Asura came to realise the value of others and the power of the friends and allies he made. Eventually, he awakened his own power which equalled Indra's own. In the anime, despite still admiring his brother's talents, he grew concerned for Indra as he continued to mysteriously grow colder and more distant to others.

In the anime, Hagoromo decided to send the two brothers on separate missions of restoration on damaged lands as test to determine which of them would be the successor to Ninshū. Along the way, Asura was accompanied by Taizō, a fellow villager who previously was helped by Asura after he was imprisoned by Indra for breaking a law for the sake if his ill mother. Eventually, their journey through a harsh wasteland found a small and mysteriously thriving village, where Asura sensed the presence of the God Tree. They were immediately met with hostility from the villagers due to recent robberies from travellers, but Asura quickly earned their trust when he healed a girl named Kanna. As Asura went to investigate the village, he found that the main hill was sealed off and guarded. He was then asked by Kanna to help heal her mother, who along with many in the village had been struck by a strange illness. While examining the mother, he noticed small roots appearing on her and a strong chakra presence. Certain that the God Tree was involved, Asura and his two friends knocked out the guards and found a small cave that lead to the inside of the God Tree.

Realising that it was the presence of the God Tree saplings that was making the land lush while simultaneously making the people sick from eating of its nutrients, Asura approached the village elder. Already having realised the truth of the God Tree, the elder regretfully declined Asura's request to destroy the saplings, noting their people had already lost so many before the sapling's emergence due to the barren land's nature. Deciding the only way to help the people was to provide them with another water source they could rely on, Asura began working tirelessly for weeks digging a well. Eventually, inspired by his selfless actions, the villagers decided to help him dig. During that time, he began teaching them Ninshū, which they used to work further their efforts to the well. After a year passed, they finally struck water, allowing a huge lake to fill beside the village. Happy of their efforts, the villagers proudly burnt down the God Tree saplings, and sick people began to heal from the fresh water and ways of Ninshū. With his job complete, Asura returned home, with many of the villagers, including Kanna, wishing to come with him to see where he learned Ninshū. Upon returning home, Asura meet with his father and elder brother, the latter of which had already completed his mission months ago.

Hagoromo selected Asura as his successor to carry out his dream of peace and understanding in the world. While Asura insisted that Indra was the obvious choice due to his superior power, Hagoromo made not that through Indra's own methods to completing his mission, he inadvertently caused the village's destruction by leaving them aimless and selfish. The following night, Hagoromo passed on his power to Asura, asking him to reach out to Indra and help him regain his compassion. As everyone began to celebrate Asura's success. Indra, jealous of his brother and further manipulated by Black Zetsu, attacked the village chose to fight Asura for the title and revenge on his father and brother. Asura pleaded for Indra to reconsider but as his words fell in deaf ears, who sternly believed power and force was the true means to obtain peace and order. As Indra began attacking the citizens, Asura awoken his Six Paths Chakra and was able to fend off Indra's attack. Realizing the fight was inevitable, Hagoromo instructed the villagers to pass on their chakra to Asura, allowing his power to full mature. Using his new power, Asura was able to defeat Indra, who fled in anger, vowing to destroy Ninshū and his younger brother.

Several years pass and Asura married Kanna, with whom he had two sons and a daughter. When Hagoromo was on his deathbed, he informed his son about a final meeting with Indra, who vowed to undo all his father's work, even in a following life. Asura comforted his father and vowed to reincarnate with Indra to continue their feud, as he hoped they would one day find a peaceful resolution. After Asura and Indra died, the descendants of both brothers continued this feud for centuries to come. Indra's eventual descendants — the Uchiha clan — would feud with Asura's eventual descendants — the Senju clan. Neither clan knew why or how their hatred of the other came to be.

Personality
In the anime, as a young child, Asura was a carefree and loving child who looked up to and happily played with his older brother. Though the son of the famed Sage of Six Paths, Asura was born with no talent and thus could not accomplish much on his own. Instead, he valued depending on and cooperating with others. In the anime, as a child, he was shown to be impatient and insecure at his limited prowess, unlike his older brother and father. Still, Asura adored Indra and would constantly devote himself to studying, aiming to be like his older brother. Even more, he strongly believed Indra would be the better choice as successor to Ninshū and made no effort in trying to claim the title. At the same time, he was a very determined person, refusing to give up on a goal once he set it. With the help of his countless friends and allies, and through sheer hard work and determination, he awakened his own power. As he never lost sight of his principles and the love he had for others, he believed love to be the key to peace. This ultimately convinced Hagoromo to anoint Asura as the successor to his Ninshū as Hagoromo wanted the world to adopt Asura's way of thinking.

When Indra started deviate from their father's philosophy and teachings by focusing on power to maintain order and rebuffing help from others, Asura, although he loved his brother dearly and was reluctant to challenge him, felt he had no choice but to fight Indra. Before any violent acts would occur between them Asura tried to reach out to Indra in hope the latter would draw away from his hatred but was unsuccessful. Despite the rivalry and hatred between the brothers, Asura always loved and respected his older brother. The inevitable battle between them would have dire consequences for their descendants.

Appearance
Asura had short, spiky brown hair — two locks of which were wrapped in bandages framing either side of his face in a similar manner to his brother. He possessed stern facial features. In his later years, he had a more pronounced jaw-line and short goatee similar to his father. He wore what seemed to be a blank forehead protector and at a later time, bandages around his forehead. He wore a light-coloured kimono with magatama adorned around the collar. The kimono was held closed by a dark-coloured sash. Underneath, he wore a black full-body suit.

Abilities
Asura was originally very unskilled. Over the years, however, he proved himself a late-bloomer as through gruelling hard work and dedication, Asura awakened his own inherited power: his father's "body" — powerful life force and physical energy, granting him power on par with his genius older brother, Indra. He was also a capable leader, obtaining countless loyal followers. It was because of Asura's philosophy that his father blessed him with his power and made him the successor to Ninshū.

Ninshū
While a much slower learner than his older brother, over time, Asura gradually improved in this art. Ultimately, he became skilled and knowledgeable enough of these teachings to pass this art on to others. He also proved to become very adept in battling with this art, able to repel his genius brother's initially attack with one of his own. He could sense the presence of chakra from noticeable distances and heal people of minor injuries. Additionally, he could put people to sleep and could perform basic taijutsu.

Nature Transformation
In the anime, learning from Indra's application of hand seals as a child, he became knowledgeable of the five elements, able to teach others to use their respective affinity. Personally, he could perform Wind Release. While admitted to it being his only element initially, he could form a sphere of wind with which he could cleanly cut through bedrock. He could later produce several of these spheres at once within a larger sphere, able to launch it as a projectile. Later, he mastered Water and Earth Release, which eventually he learned to use them simultaneously to produce the Wood Release, with which he could create a gigantic battle structure to attack with.

Six Paths Senjutsu
With the power entrusted to him by his father, Asura gained access to the Six Paths Senjutsu, allowing him to augment his abilities various techniques. Going further, he could shroud himself in the Six Paths Sage Mode. In this state, he could also fly and manifest a giant three-faced, six-armed, battle avatar, which he used to combat Indra's Complete Body — Susanoo.

Truth-Seeking Ball
Asura could manifest at nine Truth-Seeking Balls, which were composed of the five basic nature transformations, Yin–Yang Release, and Six Paths Chakra. With their malleable nature, he could produce a variety of shapes, including rods to battle with and large shields to prove multiple people. In battle, he would make use of them in conjunction with his battle avatar, proportionally increasing their individual size.

Bukijutsu
He was seen wielding a shakujō, as well as a sword on different occasions, implying at least capable skill with both.

Legacy
Though his body was destroyed, Asura's chakra would continue to exist. His chakra reincarnated into various individuals throughout history, and his reincarnations would also inherit his will. During the Warring States Period, Hashirama Senju was his reincarnation. Hashirama possessed what the people of Konoha called the Will of Fire, which many people believed in. With the help of Madara Uchiha, the reincarnation of Indra at the time, Hashirama created the very first ninja village, Konohagakure, and helped set up the ninja system. However, Madara would defect, and resumed his conflict with Hashirama. When Hashirama and Madara died, the transmigration cycle resumed. Naruto Uzumaki became the latest inheritor of Asura's chakra and will, with Sasuke Uchiha inheriting Indra's chakra and will.

Asura's ideals enabled his father to realise a new possibility for the world. Hagoromo created the nine Tailed Beasts by using the Creation of All Things Technique to separate the Ten-Tails' chakra. He gave each of them names, in the hopes that when the time came, they would be reunited as a single but different entity, and that at that time, a person would appear who would show them what true power is. When Naruto befriended them centuries later, the beasts came to believe that Naruto was this person. Ultimately, Naruto managed to do what all of the previous reincarnations had failed to do: end the rift between the two lines of the reincarnated brothers. Naruto achieved this after defeating Sasuke, who finally accepted Naruto's ideals at the end of their fight. This brought about the end of the bitter feud that had lasted for centuries. According to Black Zetsu, the reincarnations of Indra and Asura were almost always in conflict with each other and rarely worked together. Naruto and Sasuke are one of the exceptions, assuming other exceptions have existed throughout the centuries.

Trivia

 * The rivalry of Indra and Asura, and their descendants (Uchiha and Senju), is derived from Hindu and Buddhist religions. The gods, led by Indra, are in constant battle with the Asuras.
 * His battle avatar is befitting of his name, as the Asura are often depicted as belligerent beings with three faces and six arms. The Asura Path is depicted in the same way.
 * As Asura 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".
 * Through the use of shadow clones while using his Tailed Beast Mode and Six Paths Sage Mode, Naruto Uzumaki was able to combine three of the avatars into a single, three-faced, six-armed construct similar to the one Asura used in the past.