One possible fanfiction could be about a crossover where Naruto characters end up in the Highschool DxD universe. Maybe Naruto himself could attend the high school and use his ninja skills in the unique situations there. He might form new friendships or rivalries with the characters from Highschool DxD.
Well, adding Poison Ivy to a Highschool DxD fanfiction could be really interesting. She could bring her unique plant - controlling abilities to the story. Maybe she could be a transfer student with a mysterious past, and her powers could either help or create chaos in the already wild world of Highschool DxD.
Well, the art style in Highschool DxD New Anime Visual Novels is quite appealing. It often has detailed character designs that are faithful to the anime. The storylines can be engaging, with lots of character development and some exciting plot twists.
One idea could be an OC who is a dragon slayer but has a unique power that sets them apart. For example, they can absorb the powers of the dragons they slay instead of just killing them. This could lead to all kinds of new storylines as they become more powerful and are hunted by both good and bad forces in the Highschool DxD universe.
The Highschool DxD manga has indeed finished. It wrapped up after completing all the planned story arcs and providing a satisfying conclusion for the readers.
These fanfictions expand the Highschool DxD universe by introducing new characters like male Nekoshou. For example, they can create new storylines around their powers and how they interact with the existing characters in the DxD world. It might be a male Nekoshou with a special ability that changes the power dynamics in the school.