Definitely not. The 'High School DxD' universe has a lot of great aspects to explore in fanfiction, like the battles, the character growth, and the complex relationships between the different species. But'shotacon' is not something that should be part of it. It's not only unacceptable in the fan community but also goes against basic moral values.
One interesting fan fiction could be about a new character joining the school and forming unique relationships with the existing characters. For example, a transfer student from a different supernatural realm who has different powers and a different view of the world in the DxD universe.
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.
The use of fire in 'High School DxD' fan fictions can be really cool. Fire often represents power and passion. In these fan fictions, characters with fire - based abilities can do amazing things like shooting out huge fireballs or creating walls of fire for defense. It's visually exciting and can create a sense of intensity in the story.
Asta could be brought into the High School DxD fanfic as a result of a multiverse - related event. In this case, different universes are colliding or being connected in some way. His presence would disrupt the power balance as his anti - magic is something that no one in the High School DxD world has really encountered before. He could end up training with the devils to learn more about their magic while also teaching them about the concept of anti - magic.
One way could be through the power system. The EMS (Eternal Mangekyou Sharingan) from Naruto could be a unique power that a character in the High School DxD world acquires. Maybe a transfer student from a hidden ninja village arrives at the high school and has to keep their EMS a secret while dealing with the devils and angels in the school. This could lead to some interesting battles and interactions as the powers of the EMS, like the ability to use powerful jutsus, contrast with the magic and abilities of the High School DxD characters.
Another way is to join fan communities dedicated to High School DxD on social media platforms like Reddit or Facebook. Fans often share their favorite fan fictions there, and you can also ask for recommendations. Sometimes, they might even link to some hidden gems that are not easily found on the big fan - fiction sites.