It gives fans a chance to explore different 'what - if' scenarios. By seeing the Avengers' reactions, fans can get a deeper understanding of the characters.
Killua is likely to be completely devastated. He might go into a state of shock at first, not believing that Gon is really gone. Then he could become very angry, either at himself for not being able to protect Gon or at the situation that led to Gon's death.
Some fans might be disappointed. Fanfiction often allows them to explore different scenarios with Naruto's character. If he gives it up, it's like closing a door on those creative possibilities.
Gon in fanfiction can be very single - minded in his pursuit of goals, just like in the original. He might be a bit more naive at times, which can lead to interesting plot twists. Killua is often portrayed as having a complex emotional side. He struggles with his past as an assassin and his loyalty to Gon. His cool exterior may crack in some fanfictions, showing his true feelings.
The Naruto fandom would likely be very divided. Some fans would be extremely outraged as it goes against the core values and character of Naruto. They might condemn such a fanfiction.
On the other hand, there would be fans who would welcome it. Maybe they never liked the pairing in the first place or they think it adds an interesting twist to the story. They could start exploring new relationships for both Sasuke and Sakura in their own fan - created stories.
The Naruto fandom would probably react very negatively. Fans are used to seeing Naruto as a hero, a symbol of hope and growth. A fanfic that portrays him as a slave goes against the very essence of what Naruto represents. There would be a lot of criticism on social media platforms, and many fans might even call for the fanfic to be removed or boycotted.
The fandom's reaction would be quite mixed. Some fans, who are more open to extreme and creative interpretations in fanfiction, might find it an interesting and bold take. However, the majority would probably be horrified. Snape is a beloved and complex character, and this idea of him being aroused by Harry fanfiction is so far from what J.K. Rowling created. It could lead to a big debate within the fandom about the limits of fan - created content and how it should respect the original source material.
In a Naruto world fanfic, Killua would bring a whole new dynamic. He has a dark past as an assassin which could either make him a feared or respected figure. His family's training has made him physically and mentally tough. In battles, he could use his electricity - based attacks in creative ways against ninjas. But he would have to learn about things like jutsus and the ninja villages. Also, his relationship with Gon in the HxH world was important for his character development, and in the Naruto world, he might find a similar bond with a fellow shinobi, which could change his perspective on things.
There would be a portion of fans who are very against it. They are so used to the idea of Sakura and Sasuke being a potential couple that any deviation from that would seem wrong to them. They might feel that it goes against the 'canon' in a way, even though it's a fanfic.