Nine-Tails had come willingly to help Indra. As the largest portion of the chakra split off from Yuya,
he naturally sided more strongly with Indra. The Heavenly Emperor's dignity could not be defiled.
Back when he had still been Yuya's chakra, he had accompanied Yuya across battlefields, fighting powerful enemies from beyond their world!
Whenever he recalled those memories etched into his very bones, his heart surged with emotion. How he longed to follow that figure again! How could he tolerate anyone desecrating the Heavenly Emperor like this?
And so, with Nine-Tails joining the battle and offering his wholehearted help and cooperation,
the Complete Form Susanoo, paired with Nine-Tails, naturally won by an overwhelming margin!
Even when Asura unleashed Sage Art: Wood Release: True Several Thousand Hands at the end, he was no match.
"As the price of your defeat, I'll take something from you."
Indra spoke.
Then he simply left.
What he had taken was, of course, Asura's cells.
The books Yuya had left behind mentioned a way to obtain the Rinnegan.
Now, he wanted to inherit his father's power in full, giving himself a better chance of breaking the seal!
After that battle, Indra was utterly disillusioned with the world.
But after beating Asura senseless and venting his anger, he finally regained some reason.
He set aside his plan to punish the people of the world.
Still, he broke ties with Asura in the end.
Taking some Ninshu disciples who shared his ideals, he moved away from Ninshu entirely.
He also founded a clan called the Uchiha.
There, he devoted himself to his experiments in peace.
Meanwhile, after the beating from his older brother, Asura reflected painfully on what had happened.
He gazed in confusion at the moon in the sky and murmured:
"Heavenly Emperor... Father... was I