Bakugou might react with his usual anger. He could lash out at the bullies verbally or even physically, which might make the situation worse. For example, if someone makes a snide comment, he could respond with a loud and aggressive retort.
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.
Some characters might try to understand Deku's motives. Kirishima, who was close to Bakugou, would be angry at first but might also try to find out if there were any extenuating circumstances. However, many would be afraid of Deku, seeing him as a threat now that he has killed one of their own.
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.
One idea could be '5 Times Bakugou Saved the Day'. It would show his heroic side as he uses his powerful quirk to rescue people in different dangerous situations. Another idea is '5 Moments Bakugou Realized His Mistakes', which would focus on his character growth.
A '5 times bakugou fanfiction' could be really interesting. It might explore five different emotional states of Bakugou. One time could be when he was extremely angry and how that affected his actions. Another time could be when he was vulnerable, perhaps after a difficult battle. Then there could be a time when he was happy and celebrating a victory. And two more times could be related to his growth as a character, like the first time he realized he needed to change his attitude towards his friends, and the second time when he actually made a significant change in his behavior.
The teachers, especially Aizawa, would also be worried. Aizawa might give Bakugou special permission to skip classes or training until he's recovered. He'd also keep an eye on Bakugou's progress and make sure he's taking care of himself.
Eventually, he might come to accept it in a grudging way. If Izuku is wearing the clothes for a good reason, like in a team - up situation where it's part of a strategy, Bakugou might tolerate it. But he'll still probably make some snarky comments about how Izuku better not ruin his clothes.
Midoriya is often a common character. Since he has a complex relationship with Bakugou, his reaction to Bakugou's expulsion can be an important part of the story. All Might might also be included as he could be a mentor figure who tries to guide Bakugou, even after his expulsion. And Bakugou's other classmates like Kirishima would likely be there too, as they are his friends and would be affected by his leaving.
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.