One possible reason could be that Izuku realizes Bakugou's unchanging and hostile attitude. Despite his efforts to be friends or get along, if Bakugou continuously rejects him or is overly aggressive, Izuku might feel it's a lost cause.
Well, the story could take a turn where Izuku becomes more independent. He might start to shine on his own, without the shadow of Bakugou. His confidence could grow as he no longer has to deal with Bakugou's belittling.
Growth is also a major theme. Izuku's act of standing up is usually a sign of his growth, both as a person and as a hero - in - training. It shows that he's not going to be pushed around anymore and is ready to face challenges head - on, which is a big part of his journey in these fanfictions.
One popular 'izuku stands up to bakugou fanfiction' is 'Green Sparks'. In this fic, Izuku finally has enough of Bakugou's bullying and stands up in a really powerful way during a training session. It shows Izuku's growth not just in power but also in self - confidence.
All Might would probably be one of the first to try to stop Bakugou. As Izuku's mentor and a symbol of justice in the story, he wouldn't tolerate such violence. Another could be their teacher, Aizawa. He's strict and protective of his students, so he'd surely step in.
Bakugou might be initially shocked. He's used to Izuku calling him 'kacchan' for so long that it's become a normal part of their relationship. So, when Izuku stops, it could throw him off balance.
In this kind of fanfiction, it usually shows a build - up of tension between Bakugou and Izuku. Bakugou might have been constantly pushing Izuku's buttons with his aggressive behavior and taunting. This could lead to Izuku finally reaching his breaking point. For example, Bakugou's over - the - top insults about Izuku's abilities or his dreams might be too much for Izuku to bear. And when Izuku snaps, it could lead to a big confrontation between them, which can be a very dramatic and interesting plot point in the fanfiction.
In this kind of fanfiction, a likely consequence is that it changes the whole dynamic of the story. Their classmates might take sides. Some might side with Izuku out of sympathy, while others might try to understand Bakugou's actions. It could also lead to changes in the school's view on Bakugou, perhaps implementing stricter rules or counseling to prevent such incidents in the future.
The main characters are obviously Bakugou and Izuku. Bakugou is often portrayed as the instigator, with his brash and sometimes cruel behavior. Izuku, on the other hand, is the one who endures Bakugou's actions until he finally snaps.