What challenges does Naruto face while learning the three sword style in the fanfiction?

One challenge could be the physical differences in his body compared to those who traditionally learn the Black Leg Style. Naruto's own ninja training has focused on different aspects like chakra control for his shadow clones, and adjusting to the more physical and acrobatic demands of the Black Leg Style might be tough.

One challenge could be the complexity of chakra control required for Particle Style. Naruto has always had a bit of a struggle with precise chakra control.

One challenge could be controlling the space - time aspect of Kamui. It's a very complex jutsu, and Naruto, who is used to more straightforward chakra - based attacks, might struggle to understand the intricacies of warping space and time.

Another challenge is adapting his fighting style. Naruto's existing fighting style is based on his ninja training and the use of chakra. Ultra Instinct is a completely different concept. He has to figure out how to integrate the new power into his attacks and movements without losing his own identity as a ninja. For instance, he can't just abandon his signature Rasengan, but needs to find a way to use it in conjunction with Ultra Instinct abilities.

Well, for Naruto in this fanfiction, a major challenge would be dealing with the recoil of Raikiri. Since it's a powerful jutsu, it likely has a significant recoil effect on the user. Naruto would need to learn how to manage that so he doesn't get hurt every time he uses it. Also, in the world of fanfiction, there could be other ninja who don't want Naruto to learn Raikiri. They might try to sabotage his training, which would be an external challenge he has to face. And let's not forget that Naruto has his own unique fighting style. He would need to find a way to integrate Raikiri into his existing style without losing his edge in combat.

One challenge could be mastering the chakra control required. The Hidden Mist Jutsu demands a precise amount of chakra to create a thick and effective mist. Naruto has had issues with chakra control in the past, so this would be a hurdle. Another challenge might be adapting his fighting style. He's used to more straightforward and aggressive attacks, and the stealthy nature of the Hidden Mist Jutsu would require a different approach.

One challenge could be controlling it. Haki is a different kind of power compared to chakra, so Naruto would have to learn how to regulate the flow and intensity of his haki. For example, if he uses too much haki at once, it might drain him quickly.

One challenge Naruto might face is the difference in chakra usage. Shunpo seems to require a more refined and quick chakra control compared to his regular jutsu. Also, the physical aspect of it, the sudden and rapid movements, could be tough for him to master at first. He's used to more straightforward combat movements, so the agility needed for Shunpo could be a hurdle.

One challenge could be the physical strain. The Harashin technique might require a different kind of chakra control and physical movement than what Naruto is used to. For example, it could demand more precise and rapid movements, which might be difficult for Naruto at first.

One challenge could be finding enough Uzumaki descendants. Since the clan has been through so much, there may be very few left. Another might be dealing with the political implications. Other clans might be jealous or fearful of a resurgent Uzumaki clan.