In some fanfiction, it could be related to a misinterpretation of character relationships. Maybe the author has a skewed view of Naruto and Sakura's dynamic and decides to create a tragic and unexpected turn of events where Naruto kills Sakura to show the breakdown of their bond.
Another aspect could be that the author wants to create a new and different storyline from the original. By having Naruto kill Sakura, it completely changes the direction of the story, allowing for new plot developments, new character arcs for other characters in response to this event, and exploring themes like guilt, revenge, and the consequences of such a heinous act within the fan - created world.
In the Naruto fandom, such a fanfic would be very out of character for both Naruto and Sasuke. They are comrades and friends with Sakura. However, some dark or AU (Alternate Universe) fanfics might explore extreme and unorthodox ideas. But in the main canon, they would never do this as they have a deep bond with Sakura. Naruto has been friends with her since childhood and Sasuke, despite his aloofness, also values her in his own way.
There are a few reasons. One is that some fans are really passionate about Naruto and they feel that Sakura didn't treat him fairly early on. So they use fanfiction to express their dissatisfaction. Another reason could be that compared to other characters like Naruto and Sasuke, Sakura's power progression might seem less exciting to some. So they create fanfictions to emphasize this perceived shortcoming. Also, there could be a sense of competition among fans for their favorite characters, and Sakura might be the target for those who prefer other characters in the Naruto world.
There could be. Fanfiction allows for a wide range of interpretations and alternate storylines. But it's a really extreme and disturbing concept considering the bonds that Naruto, Sakura, and Sasuke share in the official story. It would be a very different take on the characters, and most fans who love the original story would probably find it hard to accept.
One possible reason could be a sudden and extreme corruption of Naruto's character. Maybe he is influenced by some dark and powerful force that makes him turn against his friends. Another reason might be a misinterpretation of a prophecy or some kind of mind - control situation.
In this fanfiction plot, perhaps Thanos' actions in the Marvel universe start to affect Naruto's world. Naruto then sets out to find the source of the disturbance. When he encounters Thanos, he is initially outmatched. But as the story progresses, Naruto befriends some of the Marvel heroes who teach him about Thanos' powers. Naruto then trains hard, combines his ninja skills with new knowledge, and in a final epic battle, he manages to kill Thanos. The story could also include Naruto's internal struggle as he is in a completely different world with different rules and enemies.
The plot could start with Naruto somehow being transported to Aizen's world. He quickly realizes the danger Aizen poses. Naruto begins to train and adapt to the new environment, learning about reiatsu. As he battles minor foes related to Aizen, he gains knowledge about Aizen's weaknesses. Eventually, when facing Aizen, he uses his ninja skills and new - found understanding of this different power system to land a fatal blow.
She might be jealous. Maybe Naruto has achieved something that Sakura has been striving for, like getting recognition from a certain person or mastering a new jutsu. Her jealousy could get the better of her and lead to her lashing out and injuring Naruto.
It could be a creative exercise in exploring how a single event, like Kushina killing Naruto, would change the entire Naruto universe. Writers might be interested in seeing how other characters would react, how the story would progress without Naruto, and how the themes of the original story would be altered. For instance, the theme of friendship and mentorship would be severely affected. It's also possible that the writer wants to shock the readers and make them think about the characters in a completely new light.
Sasuke would likely be filled with rage. He and Naruto had a complex relationship, and Naruto's death at Sakura's hands would make Sasuke seek revenge or at least demand answers. Kakashi, on the other hand, would be deeply saddened. He was Naruto's teacher and would probably feel a sense of failure.
Another reason could be that some fans are so strongly attached to Naruto that they view any character who they think treats Naruto poorly as a target for criticism in fanfiction. Sakura, at times, did seem to take Naruto for granted in the original story. So, these fans write fanfictions to express their dissatisfaction with her character. Also, it could be a creative outlet for those who want to explore a different dynamic between Naruto and Sakura, one where Naruto is more assertive against her perceived flaws.