Maybe Muu is a long - lost member of a powerful clan that has some special connection to Naruto's Uzumaki heritage. So he takes it upon himself to train Naruto to help him reach his full potential and also to preserve some ancient techniques or secrets related to their clans.
Well, perhaps Naruto could learn some unique and powerful jutsu from Muu. Maybe Muu has a special training method that focuses on Naruto's chakra control and helps him unlock new levels of power. For example, Muu might teach Naruto how to better utilize nature chakra in a different way compared to what he learned from Jiraiya.
Well, it could be about a character who is a descendant of Muu having some sort of special powers that Naruto discovers. Maybe they team up to fight a new threat in the ninja world.
Obviously Naruto would be one of the main characters. And the descendant of Muu would be the other. There could also be other supporting characters like Naruto's friends, like Sasuke or Sakura.
Naruto would gain better combat awareness. Kurama's experience in battles can be passed on to Naruto. He'll be able to read his opponents better, know when to attack and when to defend. This will make him a more formidable opponent in combat situations.
Well, in fanfiction, Naruto being trained in different ways can bring more variety to his character. He can be trained in unique fighting styles or gain knowledge that was not available in the original story. This can make him more versatile in different storylines. Also, it can attract more readers who are looking for new and exciting takes on Naruto's development.
Yes, there are likely to be such fanfictions out there. The idea of Naruto being trained by Ichigo combines two very popular anime characters from different series. Fanfiction writers often come up with creative crossovers like this. You can try searching on major fanfiction platforms to find specific works.
One possibility in this fanfiction could be that Naruto gains new and unique combat skills. Monkey D. Dragon is known for his revolutionary ideas and powerful abilities in the 'One Piece' world. Under his training, Naruto might learn different ways of strategizing and approaching battles, perhaps incorporating some of the more unorthodox fighting styles from the 'One Piece' universe. This could lead to Naruto becoming even more formidable, not just in terms of his ninjutsu, but also in his ability to lead and inspire others in a different way, much like how Dragon has an impact on the 'One Piece' world.
I'm not sure who the specific author of that fanfiction is. There are so many fanfiction writers out there that it's difficult to determine without more research.