It might be due to a lack of inspiration. Writing fanfiction requires continuous creativity, and if they ran out of new ideas related to Naruto and the ninja world, they could decide to quit. For example, they might have explored all the character arcs and plotlines they could think of within that context.
It might inspire other writers in the community. Some might see it as an opportunity to fill the gap and start creating their own unique takes on Naruto - related stories. For example, new writers could emerge trying to recreate the kind of stories the 'quitting' writer used to write.
It could also be due to personal growth. Naruto might have outgrown the ideals and limitations of being a Konoha ninja. He may have developed his own set of values that no longer align with the village's ninja system. For example, he could have found that the constant focus on missions and loyalty to the village overshadowed the importance of individual freedom and justice on a broader scale.
The story's focus would change completely. Instead of action - packed ninja battles, it could turn into a more character - driven plot about Naruto's new life. Maybe he starts a family or a business. His relationships with other characters would also change. His friends who were used to fighting alongside him would now have to interact with him in a different context, like when he's just an ordinary citizen.
For Sasuke, it could be a complex reaction. He has his own issues with Konoha, but Naruto was always a sort of anchor for him. Naruto leaving could either push him further away from the village or make him re - evaluate his own relationship with it.
He might face disappointment from his friends and mentors. His friends who were also participating in the exam might feel let down, and his mentors, like Kakashi, could be concerned about his decision and how it will affect his future as a ninja.
Perhaps Naruto quits Team 7 in the fanfiction because of a betrayal. He might find out that one of his teammates has been secretly working against him or has lied to him about something really important. This could shatter his trust in the team and make him want to leave. Or it could be due to an accumulation of small incidents. Like constantly being the one to get in trouble for the team's mistakes, or not having his opinions heard when it comes to team strategies. Over time, these little things can build up and make him feel that he's better off on his own.
If Naruto quits Team 7 in the fanfiction, it could introduce a whole new set of storylines. There could be a search for Naruto by Team 7, which would involve them exploring new places and meeting new characters. The emotional impact on the other characters would also be significant. Sakura might feel guilty, thinking she could have done something to prevent Naruto from leaving. Sasuke might be more conflicted about his own goals, as Naruto was always a driving force in his life. And Kakashi would have to deal with the failure of keeping the team together, which could lead to his own character development in unexpected ways.
One possible reason could be that Naruto realizes the Chunin Exams have become too dangerous and he doesn't want to risk his life or the lives of his friends. Maybe he sees the dark side of the competition, like how some contestants are willing to cheat or harm others to win.
One interesting masked ninja is Shinji. He is a masked character in fanfiction who was once a normal ninja but got cursed by an ancient evil. Now, with his masked identity, he tries to find a way to break the curse while also using his new - found dark powers for good in the Naruto world. There's also a masked ninja named Yuki. Yuki is a snow - style user and her mask is made of ice crystals. She is on a quest to find the origin of her ice - based powers. Another is Hikaru, a masked ninja with the power of light, who is often at odds with the darker elements in the Naruto fanfiction world.