In the fanfiction, perhaps Stain trains Izuku because he believes Izuku has the purity of heart to use power in a way that Stain deems correct. Stain could teach Izuku how to analyze opponents better, which would enhance Izuku's ability to strategize in battles. Izuku might then start to question the current hero ranking system during his training. He could grow to be a hero who is more focused on the essence of heroism rather than just fame and recognition, which would make him stand out among his peers and also cause some friction with the more traditional heroes and hero agencies.
Fanfictions related to Stain from 'boku no hero academia' can vary greatly. Some might depict him as a more sympathetic character, trying to understand his motives for his extreme actions. Others could be more action - oriented, with Stain engaging in battles that we didn't see in the anime or manga. There's also the possibility of exploring his backstory further, like his early days and what led him to become the character we know.
Izuku would likely become more cynical. Stain's views are quite extreme, and being trained by him would expose Izuku to those ideas. He might start to question the motives of other heroes more often.
It could lead to a major shift in the story's direction. Deku might have a different perspective on villains and heroism.
One common theme is the exploration of Stain's sense of justice. Since he has a very distinct view on what makes a true hero, fanfictions often delve into this concept, comparing it with the more mainstream ideas of heroism in the 'boku no hero academia' universe.
It could lead to a major shift in the story's direction. Deku might have a different perspective on heroes and villains.
One possible plot could be that Izuku discovers Rei's hidden strength. Maybe Rei has some untapped quirk potential that Izuku, with his analytical mind, helps her realize. They could team up to face a new threat in the My Hero Academia world that requires both of their unique skills and experiences.
Maybe the fanfiction could focus on Eri's growth under Izuku's care. She starts to see herself as a normal girl with a powerful quirk, not just a tool. Izuku helps her with her schoolwork, they cook together, and he tells her stories about All Might. As time passes, Eri becomes more confident and starts to think about how she can use her quirk to help others, just like Izuku does. She might even start to train to become a hero herself one day.
There's also 'Izuku's Harem Adventure'. In this fanfiction, the author creates unique scenarios where Izuku finds himself in the middle of a harem. It has great character development for not only Izuku but also the members of his harem, exploring their individual personalities and how they interact with Izuku.
The 'Hero Academia Stain' manga is like the blueprint for the anime. The anime tries to bring the scenes and characters from the manga to life on the screen. But there can be differences in how they present events or the emphasis placed on different elements.
Stain is a significant character as he challenges the traditional hero concept and causes a stir in the hero society.