What are some interesting plot ideas for 'highschool dxd hero fanfiction'?

One idea could be that the characters from My Hero Academia end up in the world of Highschool DxD. They could have to deal with the devils and angels while also trying to figure out how to get back to their own world. Another could be a crossover of the power systems, like a Quirk user from My Hero Academia having to fight using the Sacred Gears from Highschool DxD. Or perhaps a team - up between the heroes and the devils to face a common enemy that threatens both their worlds.

A plot could also focus on a new character who is a hybrid of the two universes. They have the powers of both a devil from High School DxD and a wizard from Harry Potter. They struggle to find their place in either world as they are too different from the norm in both, and they embark on a journey to create their own identity and purpose.

One idea could be exploring new power-ups for the characters. For example, Issei could discover a hidden ability within his Boosted Gear that allows him to time - travel briefly during battles, adding a new strategic element. Another could be focusing on the relationships in the future. Maybe Rias and Issei have a family and the story could revolve around their children's upbringing in the supernatural world.

One idea could be a new character joining the school who has a unique supernatural ability that no one has seen before. This could disrupt the existing power dynamics and create all sorts of interesting interactions and challenges.

One idea could be to have a new character enter the world of Highschool DxD who challenges the existing power hierarchy and calls out the flaws in the main characters' actions. For example, this new character might see Issei's pervy ways as not just a comical trait but something that is disrespectful to the female characters and start a movement to change the way things are done in the school.

Well, perhaps a fanfiction where Griselda gets transported to a different dimension. In this new place, she has to adapt quickly and find a way back home. Along the way, she meets new allies and enemies. This would be a great way to explore her character in a different setting.

One idea could be a succubus character trying to resist her natural instincts in the high school setting of Highschool DxD. For example, she might struggle with not using her powers to manipulate the male characters around her.

One idea could be a new character joining the school who has a mysterious power that both the devils and angels are interested in. This new character could disrupt the existing power balance in the school.

One plot idea could be Tiamat adjusting to the modern world in the Highschool DxD universe. Maybe she has to deal with the different social norms and the unique magic systems there.

One interesting plot idea could be the main character reincarnating as a powerful but unknown devil. They could then use their modern knowledge to revolutionize devil society. For example, introducing new forms of magic training or social systems.