Perhaps he would try to find a new team or group to work with. There could be other ninjas who share his values more closely. This would lead to a whole new set of relationships and adventures for Naruto.
It might also lead to a confrontation within Team 7. Naruto could voice his frustrations, and this could either break the team apart completely or force the other members to change their ways and try to make the team more inclusive and positive for Naruto.
His character could develop in a more assertive way. Instead of just tolerating Naruto's behavior, he might start to set stricter boundaries. This could make him a more respected figure in the Naruto universe within the fanfiction. For example, he could demand more respect from Naruto and others who have been taking his kindness for granted. This would change his image from a laid - back mentor to a more authoritative one.
If Naruto is sick of Team 7, he could start his own solo adventures in the fanfiction. This would give him a chance to grow independently and maybe learn new skills or meet new characters. Meanwhile, Team 7 would have to figure out how to function without him, which could result in some interesting character development for Sasuke and Sakura.
Another reason could be the lack of trust he feels from his teammates in some fanfiction scenarios. If Sasuke is constantly keeping secrets or Sakura is doubting Naruto's abilities, it can make him feel isolated within the team and eventually tired of being part of it.
To develop Naruto in a Naruto and Shino team fanfiction, you could focus on his growth as a leader. Show him learning to trust Shino's more reserved and strategic approach. For Shino, explore his relationships outside of the team. Maybe he has a secret hobby or interest that Naruto discovers, which helps them bond on a deeper level.
One possible way the story could develop is that the members of Team Seven gradually notice the reader's suicidal tendencies. Naruto, being the energetic and empathetic one, might try to cheer the reader up by sharing his own dreams and how he overcame hardships. Sasuke, although aloof, could show concern in his own way, perhaps by silently protecting the reader during a mission. Sakura, with her medical knowledge, could be the first to notice any physical signs of the reader's distress and try to get to the root of the problem.
Naruto and Shikamaru would have an interesting relationship. Shikamaru might find Naruto's impulsiveness annoying at first but would later learn to appreciate his determination. Naruto, on the other hand, would respect Shikamaru's intelligence and might try to learn some strategic thinking from him. With Choji, Naruto would bond over food very quickly. They could have eating contests and in the process, become really good friends. As for Ino, Naruto would probably have a bit of a rocky start. Ino might see Naruto as a bit of a nuisance, but as they go on missions together, she would see his good heart and they would become friends too.
At the start, Naruto would be deeply hurt and confused. His abandonment by Team 7 would be a major blow to his self - confidence. However, this could also be the catalyst for his growth. He would start to look inward and discover hidden strengths within himself. He might become more empathetic towards others who have been rejected or alone. His view of the ninja world would change, and he could become more of a lone wolf type of ninja. He would no longer rely on the teamwork that he once cherished, but instead find his own way to be strong. This new - found independence could lead him to make decisions that are more in line with his own beliefs rather than following the group.
His character could develop in a negative way. He may lose his trust in people easily.
His character could develop in several ways. First, he would become more independent. He'd be forced to make all decisions on his own, which could lead to him growing up faster. Second, he might become more solitary in nature. Since he doesn't have a team to bond with, he could focus more on his own goals and desires. However, this could also make him more empathetic towards others who are alone. Third, his ninja skills would likely improve at a different pace. Without teammates to spar with regularly, he might focus more on solo training techniques and develop unique skills that are tailored to his individual fighting style.
The remaining members of Team 7 could struggle without him at first. They might have to re - evaluate their own skills and teamwork. Eventually, they could either try to convince Naruto to come back or move forward and become stronger on their own.