One possible reason could be that the author is simply exploring different relationship dynamics in a creative way, but without considering the ethical implications. They might be interested in how such a relationship would play out in the Naruto universe in terms of character development and plot progression. However, it's important to note that this kind of plot is not acceptable within the context of the Naruto fandom as it goes against the family - centered and positive - value - based nature of the series.
Some people might create such a fanfic just for the shock value. They want to break the norms and create something that is completely different from the original story. It could also be that the author has a very different interpretation of the characters' relationships and is exploring a very extreme 'what - if' scenario.
Well, in the Naruto fandom, such a plot would be rather controversial. Incest - like themes are not generally well - received. The Naruto series has a strong emphasis on friendship, loyalty, and the pursuit of dreams. A plot like Hinabi being in love with her brother goes against the moral and family values presented in the original series.
Another reason could be a very dark and alternative interpretation of the characters. Maybe the writer has a different view of Naruto's character arc and how he could be pushed to the extreme. And they see Sakura as a character that could be sacrificed in this extreme version of Naruto's story. But this is a very far - fetched view considering the original story's development.
One reason could be for the sake of creating drama. Writers might want to explore how the Naruto universe would be shaken up by such an event. It could also be a way to explore different character aspects of Naruto and Hinata that aren't shown in the original, like how Naruto would react to such betrayal.
Some people might create such fanfiction for shock value. They want to stand out by coming up with the most extreme and unexpected ideas. It could also be a form of exploring the 'dark side' of a character, taking a well - loved hero like Naruto and twisting his character into something completely unrecognizable. Another reason could be that the writer has a very different and perhaps warped view of the Naruto universe and wants to express that through this very abnormal concept.
Maybe the brother is seen as more obedient and studious. In a ninja village, those traits are often highly valued. Naruto, on the other hand, is very boisterous and doesn't always follow the rules. So, in the fanfic, the family or those around them might give more attention to the brother. Also, it could be that there's some sort of prophecy or family legacy associated with the brother that overshadows Naruto, causing the neglect.
It could be a way for fans to further explore the deep connection between Naruto and the Kyuubi. Since their bond is so strong in the original story, some might take it to an extreme with the'mate' concept, thinking about how their relationship could be on a more intimate level in a different, non - canon way.
Poison or some sort of harmful jutsu effect. Maybe an enemy uses a special poison or a jutsu that slowly weakens Naruto's body. In the fanfic, this could be a new and unique type of attack that he has not encountered before, and his body is not able to withstand it, resulting in fainting.
One possible plotline could be Naruko trying to hide her feelings from Naruto at first. Then, as the story progresses, there could be small hints and moments where her love starts to surface, like blushing when he's around or getting jealous when he talks to other girls. Another plotline might involve Naruto being completely oblivious to Naruko's feelings and treating her like a normal sister, creating a lot of comical and angsty situations.
One reason could be jealousy. Maybe you have something he wants, like a special power or a closer relationship with another character in the fanfic.
One idea could be a crossover where characters from Naruto and Sekirei meet in a unique situation. For example, Hinabi could find herself in the Sekirei world and have to adapt to its rules while also using her ninja skills. Another idea is a story that focuses on Hinabi's training in a Sekirei - like setting, with new challenges and opponents that test her limits. Maybe she could form an unexpected alliance with a Sekirei character.