Perhaps there could be a tournament in High School DxD where characters from Kingdom Hearts also participate. The keyblade wielders would show off their combat skills against the devils and angels. This could lead to some interesting alliances and rivalries. The tournament could also be a cover for a greater evil that is trying to take over both worlds, and the characters from both universes have to figure it out and stop it together.
The characters from Kingdom Hearts can fit into High School DxD by being new transfer students. For example, Sora could be a friendly and energetic transfer student who quickly makes friends with some of the devils and angels. His ability to wield the keyblade could make him an interesting addition to the school's supernatural activities.
In a Naruto and High School DxD fanfiction, there could be a scenario where the protagonists of both stories meet in a neutral dimension. Issei from High School DxD might be intrigued by Naruto's ninja skills and determination. Naruto, in turn, could be curious about Issei's Sacred Gear. They could start training together, sharing their knowledge and skills, and ultimately have to face a common enemy that threatens both their worlds.
One possible fanfiction could be about Naruto characters attending the school in High School DxD. For example, Naruto's positive and determined attitude might clash with the more complex social and power dynamics in the DxD world. He could make new friends or even rivals among the devils, angels, and fallen angels.
One idea could be that Ben Tennyson somehow gets transferred to the world of High School DxD. He has to keep his alien forms a secret while dealing with the devils, angels, and fallen angels in the school. Maybe his Omnitrix could be misinterpreted as some kind of powerful devil device.
One possible fanfiction could be about Naruto characters somehow ending up in the world of High School DxD. Maybe Naruto's skills in combat and his determination would make him a formidable opponent in the battles that often occur in the High School DxD universe. He could form interesting alliances or rivalries with the characters there.
A fanfiction could focus on Naruto's training regime influencing the characters in High School DxD. His intense physical and mental training could inspire the students at the school. They might start incorporating some of his training methods, like running up trees or on water, to improve their own strength. And Naruto could also learn from their magic-based training and combine it with his chakra control for new and powerful techniques.
A fanfiction might explore how the power of the Excalibur in High School DxD would interact with Naruto's chakra. Since the Excalibur is a powerful holy weapon, it could have some interesting reactions when in the presence of Naruto's unique chakra, which is different from the magic in the High School DxD world. For example, it could either enhance or nullify certain abilities depending on how the author writes it.
It could also be due to the fact that some fanfiction might promote values that are not in line with the general community standards. For instance, if it contains excessive violence or promotes negative stereotypes, the platform or relevant authorities may decide to ban it to maintain a healthy and positive creative environment.
There could be. Fanfiction writers are known for their wild and creative ideas. Since both Naruto and High School DxD are popular series, someone may have written a fanfic where Naruto is presented as a god - like figure within the High School DxD universe. This could add an interesting twist to the story, perhaps bringing in Naruto's unique powers and abilities into the High School DxD world.