The characters would have a range of reactions. Some would be in disbelief. They have witnessed Deku's journey from a quirkless boy to a powerful hero - in - training. So, seeing him as a villain in a fanfiction would be like a complete 180 - degree turn. Midoriya's mother would be devastated. She has always supported her son, and to see him as a villain would go against everything she believed in. The teachers at U.A. would be concerned and start to analyze what could have led to this change. Maybe they would question their own teaching methods or if there were any signs they missed during Deku's time at the school.
His friends would be really shocked at first. Uraraka might be the first to try and comfort him, seeing as she has a kind heart. Bakugo, on the other hand, would probably be both confused and a bit angry at the situation. All - Might would likely feel a sense of responsibility to protect Deku even more than before. The teachers at UA would probably start researching how to reverse the transformation immediately.
Bakugo would be deeply affected. He might initially deny his feelings, but then would be filled with guilt for all the times he was mean to Deku. He could become more withdrawn and focused on becoming a hero worthy of Deku's sacrifice.
There's also 'Growth Together'. This fanfic shows how Deku and Todoroki support each other during tough times at UA. They face challenges not only from villains but also from within the school. Their relationship develops as they help each other overcome these obstacles.
One idea for a Deku's Quirk fanfiction could be exploring what would happen if Deku's quirk manifested in a different way. For example, instead of having to gradually control One For All, he suddenly has full mastery from the start. This could lead to a very different story arc where he is immediately seen as a top - tier hero - in - training, causing envy and admiration in equal measure among his classmates.
One idea could be a fanfiction where Deku's quirk suddenly mutates. Instead of just having One For All, he starts to develop an additional power related to it, like the ability to share a fraction of One For All's power with his friends temporarily to boost their own quirks in a time of great need.
There are fanfictions where Deku teams up with unexpected characters. For example, he might partner with a minor villain who has a change of heart. This creates interesting dynamics and new story arcs that deviate from the original plot but still stay true to Deku's character.
Well, in such a fanfiction, it could be due to various reasons. Maybe Ochako realizes that their hero paths are leading them in different directions. It might also be a plot device to create more drama and character development for both Deku and Ochako.