In the fanfiction, it could be due to a powerful enemy's attack that has affected his breathing ability. For example, if the enemy has used a special jutsu that restricts air intake or affects the lungs. It might also be related to some kind of poison or gas in the environment that he has been exposed to, which is a common plot device in many fictional stories.
Perhaps it has something to do with his own internal chakra imbalance. If his chakra is disrupted in a certain way, it could potentially lead to problems with his physical functions, such as breathing. Another possibility is that he is in a high - stress situation, like a life - or - death battle, where his body is so tense that it affects his normal breathing pattern.
Maybe he's in a tight situation like being trapped in a small space or under some kind of magic spell.
One reason is that some fanfiction authors may lack a deep understanding of Naruto's character. They might write things that are completely contrary to his values and personality just for the sake of creating a 'unique' story. For example, Naruto is known for his positive attitude and strong will, but in some fanfictions, he could be depicted as a negative or spineless character.
One reason could be that some fans are very purist about the original Naruto story. They might feel that fanfiction often distorts the characters or the plot in ways that go against the essence of what Naruto is all about. For example, changing a character's personality completely to fit a romantic or dark and edgy narrative that doesn't align with the source material.
There are several possible reasons. For one, it could be a way to subvert the expectations of the Naruto character. In the original series, he's so pure and full of life. By having him smoke in fanfiction, writers can create a contrast. It might also be used to set a certain mood, like a gritty or more adult - oriented atmosphere. Additionally, it could be a symbol of his rebellion or a sign of him breaking away from the norms of his ninja village. Writers might use it to explore a different side of Naruto that wasn't shown in the original story.
One reason could be to explore a different character arc. Writers might want to see how Naruto would develop if he had a more violent nature from the start. Another reason is to add drama. A bloodthirsty Naruto would create more conflict within the story, especially with his friends and the village. Also, it could be a way to show a more 'realistic' or gritty version of the Naruto world, where characters are not always so morally upright.
One reason could be the waning popularity of the Naruto franchise over time. As new shows and series emerge, some fans shift their attention away. Another factor might be that the quality of fanfiction has declined. With so many people writing, there's a lot of poorly written stuff that turns readers off.
One reason could be that Naruto has always been more attracted to those who understand his outcast past better. Sakura doesn't really have that kind of connection with him as she comes from a more normal background. So there's a lack of that fundamental understanding between them which hinders any romantic feelings.
One possible reason could be a miscommunication between them. Maybe Anko feels neglected and then strays. Another reason might be that the writer wants to create a more complex and angsty plot.
One possible reason could be that the writer lost inspiration. Jiraiya has a complex character in the Naruto series, and it might be difficult to keep coming up with new and interesting plotlines for him in fanfiction. Another reason could be that the writer got involved in other projects or fandoms and simply didn't have the time to continue with the Naruto fanfiction centered around Jiraiya.
One possible reason could be that he breaks some important rules within the fan - created world. For example, if the fanfiction has a strict code of honor and Naruto is made to cheat in a crucial competition, that could lead to his disqualification. Another reason might be that he is framed by an antagonist. The antagonist could plant false evidence against Naruto, making it seem like he has violated the rules, thus getting him disqualified.
One possible reason could be that the fanfiction misrepresents the true essence of Konoha. Naruto has a deep connection to Konoha, and if the fanfiction distorts its values, he might despise it.