Originally, Naruto had not intended to bring Hinata and Hanabi here.
His plan had been to deal with the moon's deepest secret alone.
However, he had encountered an obstacle he could not bypass.
The final passage to the place where Kaguya was sealed seemed to require a specific "key" to open.
And according to Naruto's tests and analysis, that "key" had to possess Hamura Otsutsuki's bloodline to activate it.
Although Naruto's own bloodline shared its origin with the Sage of Six Paths, Hamura's brother, it belonged to a different branch and could not open this "door."
Nor could he simply split the moon apart and search it at his leisure. He still had a use for it later.
Left with no choice, he could only seek out Hinata and Hanabi.
After opening the passage, Naruto had originally intended to have the sisters wait outside while he entered alone. After all, a legendary, dangerous being was sealed inside, and he did not want them taking that risk.
Just as Naruto was about to step into the Sealing Space, an elderly soul suddenly appeared and blocked his path.
It was the remnant of Hamura Otsutsuki's spiritual consciousness.
Hamura insisted that Hanabi and Hinata come in together.
He seemed to have keenly sensed some "dangerous" intent in Naruto, and believed that the two Hyuga princesses with their pure Byakugan might influence him and stop him from taking any other extreme actions.
Faced with this ancient soul, Naruto really had no good solution for the moment.
He had never learned the Spirit Transformation Technique and could not directly engage a soul in any substantive battle or confrontation.
Force his way through?
Never mind how he would break past a Six Paths-level soul; the contingencies Hamura might have left behind were enough to make Naruto