After entering Sage Mode, Naruto's strength had already stepped into the ranks of Super Kage, and even among Super Kage fighters, he could be considered fairly strong.
As the Nine-Tails Jinchuriki, Uzumaki Naruto only needed to reach an agreement with the Nine-Tails inside him to become a Super Kage powerhouse in the shortest possible time. Uchiha Shūichi's Kotoamatsukami Mangekyo had undoubtedly greatly shortened the time needed for the two to adjust to each other.
Just as Uzumaki Naruto successfully became a Perfect Jinchuriki, Second Pillar found traces of his older brother on the other side.
All along, Second Pillar had been searching for his older brother, Uchiha Itachi, hoping to free him from the genjutsu.
Unlike in the original work, although this Uchiha Itachi had also killed his father, he had not massacred the entire Uchiha Clan. It had also been confirmed long ago that he was under Danzo's genjutsu control.
Thus, Second Pillar held no hatred toward Uchiha Itachi. Instead, he had always wanted to rescue his brother from Shimura Danzō's hands.
However, all of this had actually been under Uchiha Shūichi's control. During the Chunin Ninja Exams two years ago, Uchiha Itachi had not appeared when the battle began precisely to prevent Second Pillar from noticing anything strange.
Second Pillar had also never discovered that Shimura Danzō's Root was still under Konoha's control.
It had to be said that, because of their personalities, the Uchiha Clan was indeed easily manipulated into becoming pawns. Their overly extreme temperaments made them especially easy for others to guide.
This time, under Tobirama Senju's intelligence-based guidance, Second Pillar had directly found traces of Root and gradually uncovered information about his brother.
During this process, the ninja companions around Second Pillar had all gone off after finding other leads. In the end, only