Kakashi would be deeply affected. He has mentored both Sasuke and Sakura. This would make him question his own teachings and his ability to protect his students. He might also feel a sense of responsibility and could become more involved in trying to bring Sasuke to justice or at least understand what drove him to such an extreme act.
For characters like Itachi, if his spirit or some form of his consciousness was still around in the fanfiction, it would be a complex situation. He sacrificed so much to protect Sasuke, and now Naruto killing him would be a huge irony. Itachi might try to influence the events from the afterlife or through some other means. And Hinata, who loves Naruto, would be deeply concerned for Naruto's state of mind. She would try to support him, but also struggle with the moral implications of what he has done.
One possible motive could be that Sasuke is so consumed by his thirst for power and revenge that he sees Sakura as a liability or a distraction. He might think that she would try to stop him from leaving the Leaf Village to pursue his own dark path, and in his warped state of mind, decides to eliminate her.
It would surely cause a great shock among the different factions in the Naruto universe. The existence of an angel attendant might have been something that many held in high regard or were even afraid of. Naruto killing one would make him a controversial figure. Some might see him as a hero for eliminating a potential threat, while others might view him as a murderer.
It would likely strain their relationship at first. Sakura would probably be very angry and hurt, both physically and emotionally. She might start to question Naruto's true nature and whether he really was the friend she thought he was.
A Sakura cheating on Sasuke fanfic would have a significant impact. Firstly, it would change the perception of Sakura's character for many fans. Those who view her as a loyal and loving partner would be disappointed. Secondly, it could inspire new fan art and discussions. Some fans might create art based on the angst and drama of the situation. And thirdly, it might even lead to some fans re - evaluating their love for the Naruto series as a whole if they feel the fanfic goes too far against the essence of the original relationships.
Sakura would be devastated. She has always had deep feelings for Sasuke. She might initially be angry with Naruto, thinking that there could have been another way. But later, she might understand Naruto's difficult decision when she realizes the threat Sasuke posed.
The rest of the Konoha villagers would be in shock. Naruto is seen as a hero in the village, and Sasuke was once a part of the village too. The idea of Naruto turning on Sasuke like that would make the villagers question Naruto's judgment and stability. It could also create a divide among those who support Naruto's actions and those who think he's gone too far.
For Kakashi, it would be like losing his student all over again. He has trained Naruto and seen his growth. His death would make Kakashi question his own role as a teacher and mentor. He might become more withdrawn and blame himself for not being able to prevent Naruto's suicide.
The other students would likely spread rumors. Some might idolize Hermione for her bravery in taking on a troll, while others might be afraid of her. This could lead to a change in her social standing at Hogwarts. She may become more isolated as some students avoid her, or she could gain a group of followers who admire her boldness.
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.