One possible storyline could be Naruto's struggle to adapt to his new physical state. He might have to relearn all his ninja techniques, now that he's missing an arm. For example, he'd have to find new ways to perform his signature Rasengan. Another could be his journey of self - acceptance, dealing with feelings of inadequacy compared to his former self. He could also face challenges from enemies who see his injury as a weakness and try to take advantage of it.
His combat abilities are severely affected. Naruto is known for his physical combat skills combined with his chakra - based attacks. Without his right arm, his punches and grappling moves are limited. He can't hold his kunai or shuriken as effectively in combat, which reduces his ranged attack options.
One possible fanfiction could be about Naruto's right arm gaining a new and mysterious power. Maybe it starts to glow with an unknown chakra, and he has to figure out how to control it without losing himself. It could be a power that has a connection to an ancient ninja clan's secret technique.
One possible consequence could be a significant change in his fighting style. He might have to rely more on his left side and develop new jutsu techniques that can be executed with one arm. For example, he could focus on enhancing his Rasengan further to compensate for the loss of his right arm's abilities.
Another way his story could progress is that he becomes a symbol of resilience. Despite the loss of his arm, he continues to fight for his village and protect his loved ones. This could inspire the younger generation in the fanfiction, showing them that physical disabilities don't mean the end of one's capabilities.
His right arm could get a cool tattoo that gives him extra powers. For instance, a tattoo that allows him to summon a special type of animal or use a unique jutsu.
Maybe he was protecting someone in Wave. He's always the self - sacrificing type, so he could have put himself in harm's way to save a villager or a friend.
Another possibility is that Naruto and Yang have a special bond. This bond could be formed through shared experiences, like they both went through a difficult training together or survived a life - threatening situation. Because of this special connection, Naruto feels indebted to Yang or simply values Yang's life more than his own arm.
Maybe he starts to train with one - armed techniques. He could learn from other one - armed ninjas if there are any in the fanfiction world. His friends would also play a big role. They might encourage him to keep going or help him in his training.