Power dynamics are often a theme. Spiderman has his own set of powers, and in the High School Dxd world, there are various power levels among the characters. There's also the theme of adaptation. How does Spiderman adapt to this new, very different environment? And of course, there could be themes of heroism, as he continues to do what he does best - save the day, even in this new and strange setting.
One common theme is the clash of different worlds. Spiderman's world of superheroics and the supernatural world of High School Dxd collide. Another could be friendship, as Spiderman might form new bonds with the characters in the High School Dxd universe.
Yes, there are quite a few out there. You can start by looking on fanfiction websites like Archive of Our Own or FanFiction.net. Just search for 'Spiderman High School Dxd' and you'll likely find some interesting stories.
Transformation is also a popular theme. Given ACNologia's nature, fanfictions may involve him undergoing some sort of transformation, either physically or in his personality. This can be due to the influence of the High School DxD environment or his interactions with the characters. And this transformation can then drive the plot forward in interesting ways.
Friendship is also a big theme. Characters from both universes form new friendships and alliances. For example, Naruto's idea of comradeship might influence the characters in High School DxD and vice versa. They learn from each other's values and work together to face challenges, whether it's school - related in the High School DxD setting or something more global like in Naruto's world.
One common theme is the exploration of relationships. Given the nature of the original series, many fanfictions focus on the romantic or friendship relationships between Uri and other characters.
One common theme is power growth. Many fanfictions focus on the main character getting stronger in the High School DxD universe, whether it's through new powers or better control of existing ones.
One common theme is Asia's growth. Since she starts as a rather timid character in the original, fanfictions often focus on her becoming stronger. Another theme is her relationships, like her friendship with the main characters.
One common theme is power growth. In both Naruto and DxD, the characters are constantly striving to become stronger. Fanfictions often combine these two elements, showing how characters from one series adapt to the power - up systems of the other. For example, Naruto characters might learn about the Sacred Gears in DxD.
A prevalent theme is the adaptation to a new environment. Dean, coming into the High School DxD universe, has to adapt to the different rules, cultures, and power dynamics. There are also themes related to loyalty and betrayal. In many fanfictions, Dean has to figure out who he can trust among the various characters, some of whom might be plotting against him while others are true friends.
One common theme is the clash of different ideologies. Since Alexander Anderson has his own set of beliefs and values, when he enters the High School DxD world, which has its own complex moral and power structures, there is often a conflict. For example, his strict sense of justice might not always align with the more chaotic and self - interested nature of some DxD characters.
One common theme is power. Since the OC is a god, there's often a focus on their extraordinary powers and how they use them in the high school setting of DxD.