Naruto could develop a new sense of determination. Dealing with issues related to his nervous system would be a huge challenge. But he has always been one to overcome difficulties. This could lead to him being even more focused on achieving his goals, whether it's becoming Hokage or bringing peace to the ninja world. He would see this as just another obstacle in his path, and his resolve would strengthen as he finds ways to adapt and grow.
His character could develop in terms of his relationships. If his nervous system gives him new abilities, he might be feared or misunderstood by some. This would force him to reevaluate his friendships and alliances. He might also become more protective of those close to him, fearing that his new condition could put them in danger.
Naruto would likely become more versatile. With the blue lightsaber, he'd have a new weapon that requires different combat skills. This would force him to be more strategic in battles. For example, he'd need to learn precise strikes instead of just relying on his brute force and ninjutsu.
His character could also grow in terms of his self - expression. Usually, Naruto is loud and boisterous, but through singing this song, he could find a new way to communicate his deeper feelings. He might become more in touch with his sensitive side, which could change the way his friends and the villagers perceive him. For example, they may see him not just as the hero who saves the day, but also as a person with his own complex emotions.
Training sessions could be a major factor in character development. Just like Naruto trained hard, his kid would too. During training, they could face difficulties and setbacks, which would teach them perseverance. They might also learn new jutsu and in the process, develop their own unique style, which would also shape their character.
Naruto's character would likely become more self - reliant. Without a mother figure, he'd have to learn to take care of himself from a young age. This could make him more independent in his decision - making and less likely to rely on others for emotional support.
Naruto might become more cautious. Losing an arm would make him realize his vulnerability more. He would probably be more strategic in battles, relying less on brute force and more on his intelligence and remaining ninja skills.
Naruto's character would be deeply affected. He would feel a great sense of betrayal. His usually sunny disposition could turn into a more cynical one. He may start to question the values of the village he once so desperately wanted to be a part of. However, this could also be the catalyst for him to explore his own identity outside of the village's expectations. He could become more self - reliant and develop a new sense of purpose that is not tied to the village's approval. He might also have a more complex relationship with his sister, feeling both envy and a strange sense of protectiveness towards her, especially if he realizes she was also a victim of the village's decision in some way.
The twin brother's character might be developed based on his past. If he had a difficult childhood, it could make him more reserved or cautious. But as he gets to know Naruto and Sakura, he starts to open up. He could start as a loner type, but as he gets involved in their adventures, he becomes more social and confident. He might also develop his character by exploring his own unique abilities and how they can be used for good.
Naruto could develop his strategic thinking skills. By scaring Zabuza, he realizes that he can use psychological warfare in addition to his regular combat skills. So he starts to study his opponents more closely to find their weaknesses.
Perhaps in the fanfic, an enemy targets Naruto's nervous system with a special jutsu. As a result, he starts experiencing strange sensations and visions. His friends then have to find a way to reverse the effects while Naruto battles against the mental and physical chaos.
In the fanfiction, Naruto might develop new skills related to Kaguya's power. As he delves into her story and the nature of her abilities, he could learn to control or even mimic some of her powers. This would not only make him stronger but also change his fighting style. His understanding of the origin of chakra and the world itself would deepen, which could lead to him being more of a philosopher - like figure in the fanfiction. He might start to question the cycle of hatred in a more profound way, seeing how Kaguya's actions were influenced by her own experiences. Also, his relationships with other characters could change. For example, if he discovers that Kaguya had some connection to certain characters in the present, he might treat those characters differently or have a newfound respect for them.