It would be quite an odd scenario. A character from Medaka Box, used to their own world of challenges and relationships, would probably be very confused reading Highschool DxD fanfiction. The two worlds have different power systems, character dynamics, and overall tones. For example, a character like Medaka herself, who is used to solving problems in her own way in the Medaka Box world, might find the more supernatural and often risqué elements of Highschool DxD fanfiction very strange.
There is no direct relation between Medaka Box and reading Highschool DxD fanfiction. Medaka Box is its own story with its own characters and plot, while Highschool DxD fanfiction is based on the Highschool DxD universe. They are two separate entities in the world of anime and manga.
A Spiderman and Highschool DxD fanfiction might involve Spiderman teaming up with Issei. Spiderman could teach Issei some new combat moves based on his acrobatic fighting style. And Issei could introduce Spiderman to the unique aspects of the Highschool DxD world, like the different factions and the power of Sacred Gears. They could go on adventures together, facing off against powerful foes that threaten both their worlds.
A 'Naruto Bijuu Highschool DxD' fanfiction might have some really cool crossovers. For example, the Bijuu could be seen as a new kind of power in the Highschool DxD universe. The students might be in awe or fear of Naruto and his connection to the powerful Bijuu. And Naruto, being the friendly guy he is, could try to use his powers for good in this new and different environment, like helping out in fights against the evil forces in the DxD world.
It would probably be really interesting. Naruto's skills and abilities as a 'god' would likely disrupt the normal flow of the Highschool DxD world. Maybe he'd use his ninja techniques in battles against the devils and angels in that universe.
Well, the Skyrim Dragonborn in a Highschool DxD fanfiction could be a really powerful and mysterious character. They might have their dragon - slaying skills and Thu'um at their disposal. Maybe they would be seen as an outcast at first because of their different abilities, but then prove themselves in battles against the devils or other threats in the DxD world.
The female characters from Highschool DxD, like Rias, would be intrigued by the unique personalities of the Naruto characters. Rias might see potential in some of them to join her peerage. And the Naruto girls, like Sakura, would be a bit shocked at first by the more revealing outfits and flirty nature of some of the Highschool DxD characters. But over time, they would bond over things like protecting their friends and the school. The Naruto boys would respect the power of the Highschool DxD devils and might even try to incorporate some of their fighting strategies into their own ninja combat styles.
It would probably be really wild. Picture Harry Potter in the Highschool DxD world with all its unique characters and concepts. Maybe Harry would have to deal with the devilish and angelic beings in a whole new way, using his magic skills from the Potterverse.
Naruto himself would be a great choice. His sunny personality and strong will would contrast with the more complex and often morally ambiguous characters in Highschool DxD. He could bring a sense of innocence and pure determination to the world of DxD, and his unique jutsu would be a new and exciting addition to the battles there.
If Issei got the Time Stone, he might use it to go back and prevent some of the tragedies that happened in his life, like the times he was bullied. But this could also have unforeseen consequences, like messing up the timeline of the Highschool DxD world.
A fanfiction like this would be full of interesting twists. Naruto, being an angel, might start off as an enigma to the characters in Highschool DxD. His physical abilities, which are already impressive in the Naruto series, could be enhanced with angelic traits. He could have wings that not only allow him to fly but also serve as a weapon or a shield. His relationships with the female characters in Highschool DxD could be complex, as he's used to his own set of female companions in Naruto. And his journey in this new world could be about finding his place among the angels, devils, and other factions while still holding on to his own identity.