It could also be due to a power struggle. Fem Sasuke might be jealous of Naruto's growing power and influence. In some fanfictions, characters can be driven by envy, and she might see Naruto as a rival that needs to be put in her place, so she ends up hurting him.
One possible reason could be that it goes against the original dynamic between Naruto and Sasuke. In the original story, their relationship is based on a deep male - male bond of rivalry and friendship. Changing Sasuke to a female might disrupt that established connection.
Well, it's hard to say for sure if Sasuke is obsessed with fem Naruto fanfiction. It could be that some fans like to explore different gender dynamics in the Naruto universe through fanfiction. Maybe they see an interesting potential in a female Naruto interacting with Sasuke in new and unique ways. But this is more of a creative exploration by fans rather than something based on the original canon.
It could be due to the fact that Naruto is always in the spotlight. Fem Sasuke might be obsessed because she wants to be like him in some ways or wants to understand what makes him so special. Also, their rivalry in the original series might translate into a different kind of intense feeling in this fanfiction, like an obsession.
Naruto might initially be shocked. Given his friendly nature towards Sasuke in the original story, he wouldn't expect such an attack from her. So, his first reaction could be pure disbelief.
One possible reason could be jealousy. Maybe fem Sasuke is jealous of Naruto's natural charisma or his ability to make friends easily. Another reason might be related to their different goals. If fem Sasuke has a very different view of how to save or change the ninja world compared to Naruto, it could lead to hatred.
One possible reason could be competition. Maybe in this fanfic, they are competing for something like recognition in the ninja world. Naruto, as a female, might feel that Sasuke is getting more attention or opportunities, which makes her jealous and eventually turns into hatred.
Maybe he got injured during a fight. In the Naruto universe, battles are fierce. If he was hit in the back by an enemy's jutsu or weapon, it could cause lingering pain. Say he was caught off - guard by an opponent's sneak attack from behind, that could easily damage his back.
One reason could be the author's desire to create drama. By having such a betrayal, it amps up the emotional turmoil. Another could be to explore different relationship dynamics. Maybe the author wants to see how Naruto would react to such a situation, which is a way of testing the limits of their bond.
Well, Naruto has always been there for Sasuke in the original story. In fanfiction, Fem Sasuke might secretly like Naruto because she sees his loyalty. He's constantly trying to bring Sasuke back to the right path. This loyalty could translate into a deeper affection in the fan - created stories.
One reason could be a misinterpretation of their complex relationship. In the original story, Naruto actually cares deeply for Sasuke. But in fanfiction, the author might be exploring a 'what if' scenario where Naruto's frustration turns to hate due to Sasuke's repeated betrayals. Another reason could be to create a more angsty or dramatic plot. By having Naruto hate Sasuke, it can introduce new conflicts and character developments that are different from the canon.