Deku might be completely shocked at first. Since Bakugou has always been so aggressive towards him, he would never expect such a confession. He might just stand there, mouth agape, not knowing what to say.
Some bullies might mock or make fun of spiderman fanfic. They could see it as something only 'nerds' are into and use it as another reason to pick on fans. For example, they might laugh at the outlandish plot ideas or the 'geeky' passion of the fans.
Deku's experiences with being bullied for not having a quirk. This would be important because it shaped Deku's character and his insecurities. Aizawa might focus on this to better understand the root of Deku's drive and his sometimes over - eager nature to prove himself. It also gives Aizawa more insight into why Deku is so desperate to be a hero despite the odds.
He might cry a lot. Deku is very emotional, and being cheated on would be a very painful experience for him. He could also get angry, which is rare for him, but this situation would be so unjust that he might not be able to hold it in. He'd probably start to question his self - worth too, thinking that there was something wrong with him that made his partner cheat.
They're popular because they play on the idea of the members of BTS being in a difficult situation. Fans like to see how their idols would react to something like being wrongly accused of bullying. It gives a chance to explore different sides of their personalities.
One popular 'BTS Bullies React' fanfic might be 'The Change'. In this fanfic, the members of BTS react to a situation where they are wrongly perceived as bullies. It has an interesting plot that shows their shock and determination to clear their names. Another could be 'BTS Bullies React: The Hidden Truth' which delves into a mystery surrounding false accusations of bullying against them. It keeps you on the edge of your seat with its twists and turns.
Deku might be initially shocked. He's used to Bakugou's aggression, but an actual injury is different. He could be in pain and disbelief at first. Then, he might try to downplay it, especially if he doesn't want to cause trouble for Bakugou, because Deku is generally a very forgiving character.
Percy could react by ignoring Clarisse at first. He might think that if he doesn't give her a reaction, she will stop. But when that doesn't work, he could start to fight back verbally, using his quick thinking to come up with comebacks.
Well, some might be really amazed. They could see a new side of Deku that they never knew before. His singing might show a different level of confidence or a hidden talent, so they would probably cheer him on.