Naruto's overpowered nature would have made him too strong if he retained the balls, affecting the Boruto series. Naruto ...

The characters in Naruto feature some truly mind-blowing ... realm that could only be seen or touched by those of Six Paths powers. Madara was absolutely incredible as a user of the Rinnegan.

And by opening the Eighth Gate, the Gate of Death, Guy can make himself powerful enough to go toe-to-toe with Six Paths Madara Uchiha. No one else at the start of Naruto can reach the same heights ...