While the Tailed Beasts united against their common enemy, the two Senju brothers were both busy within the Senju Clan.
Tobirama Senju was busy researching and refining his Flying Thunder God Technique. For its sake, he even swallowed his pride and sought guidance from Uchiha Sora.
Uchiha Sora did not hold back either. He explained many of the Flying Thunder God Technique's key points one by one, clearing up numerous questions for him.
Tobirama Senju could not help feeling deeply grateful.
Yet he had no idea that the Flying Thunder God Technique had originally been created by his counterpart in another world.
That day, in an open training ground within the Senju Clan's grounds, Uchiha Sora was set to spar with Hashirama Senju at his own request.
Hashirama Senju's strength was beyond question. During the earlier battle against Kaguya Yakki, he had actually come to their aid while in poor condition, so he had not displayed his full power.
His true strength certainly went far beyond that.
Uchiha Sora had proposed sparring with Hashirama Senju not because he was itching for a fight, but because he had a goal in mind.
His physique had been undergoing Automatic Training all along, evolving toward a Hashirama Sage Body. At its original rate, the evolution would take roughly three years, about as long as it would take to evolve his eyes into the Eternal Mangekyō Sharingan.
But that did not mean there were no other methods. The system had previously adjusted the time needed to evolve his Hashirama Sage Body in response to an external stimulus.
That was why he had decided to exchange blows with Hashirama Senju himself and see whether it would prompt a response from the system. With luck, it might greatly shorten the time needed to evolve his Hashirama