Asura's birth came with problems, which led to the untimely passing of his mother. Despite this loss, 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.
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 of 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 by eating 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 met with his father and elder brother, the latter of which had already completed his mission months ago.
On his deathbed, Hagoromo selected Asura as his successor to carry out his dream of peace and understanding in the world. Hagoromo chose Asura after seeing how each brother carried out the mission. While Asura insisted that Indra was the obvious choice due to his superior power, Hagoromo made note that through the methods Indra used in 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 and chose to fight Asura for the title of successor while also seeking revenge on his father and brother for denying him his birthright. Asura pleaded for Indra to reconsider, but his words fell on deaf ears, since Indra sternly believed that power and force were the only true means to ensure peace and order were obtained. As Indra began attacking the citizens, Asura awoke his Six Paths Chakra and was able to fend off Indra's attack. Realising this fight was inevitable, Hagoromo instructed the villagers to pass on their chakra to Asura, allowing his power to fully mature. Using his new power, Asura was able to defeat Indra, who fled in anger while vowing to destroy Ninshū and his younger brother as well.