There might be a new character created specifically for this fanfiction. This character could be the mastermind behind forcing Izuku to be a hero. They could have a complex backstory and motives, like believing that only Izuku can save the world from a new and upcoming threat, but going about it in the wrong way by forcing him instead of giving him a choice.
There could be his friends like Ochaco Uraraka. She might be in a position where she's trying to understand Izuku's situation and help him. Maybe she tries to convince the people forcing Izuku to give him some space.
There could be other U.A. teachers like All Might. He might play a role in Izuku's development even though Midnight has adopted him. Another character could be Bakugo. His relationship with Izuku could change or be explored further in this fanfiction.
His classmates like Bakugo could be a main character. Bakugo might be one of the first to notice the strange changes in Izuku and could be both scared and angry about it. He might try to confront Izuku, which could lead to some intense scenes.
All Might would probably be in it. Since he's Izuku's mentor, he could play a role in helping Izuku understand and control his time - controlling power. Maybe he has some past experience related to time powers that he shares with Izuku.
Definitely include All Might. He could be like a guiding figure for Izuku during the summer. He might give Izuku special summer training or pass on some important wisdom. Another character would be Iida. His strict sense of order and strong leadership skills could be useful in a summer group activity with Izuku. For example, they could be part of a team that has to organize a big hero - themed event. Also, consider adding Mei Hatsume. Her crazy inventions could play a role in Izuku's summer. She could create some new gear for him to use during his summer training or adventures.
Well, in many izuku goes back in time fanfictions, besides Izuku himself, his mother is an important character. He might go back in time to be a better son, protect her more, or even change things that affected her in the past. Another often - seen character is Aizawa. As Izuku's teacher, Izuku could use his time - travel knowledge to impress Aizawa earlier or get more help from him in his hero training. And of course, the villains like Shigaraki could also be involved. Izuku might try to stop Shigaraki from becoming a villain by going back in time and changing certain events that led to his fall.
One could be All Might. Even if Izuku leaves Japan, All Might might still be in contact with him, guiding him from afar. Another could be Bakugo. Their relationship is complex, and Bakugo might have some sort of reaction to Izuku leaving, perhaps feeling a sense of rivalry still and trying to prove he can be a great hero in Japan while Izuku is away.
Bakugo is often paired with Izuku. Their complex relationship can add a lot of drama to the detective story. Bakugo might be reluctantly helping Izuku or even be a suspect in the case Izuku is investigating.
One possible plotline could be Izuku's struggle against the forced heroism, like trying to find his own identity within the constraints. Maybe he starts to question the true meaning of being a hero when it's forced upon him.
Obviously, Izuku is one of the main characters since the title mentions him. He's the demigod in this fanfiction.
There could be a mysterious Pokemon that Izuku discovers early on in the story. This Pokemon could have some sort of special power or connection to Izuku. It could be a key factor in his development as a Pokemon fan and as a hero. The Pokemon might not be fully understood at first, and Izuku's journey to figure out its secrets could be a major part of the story.