One idea could be that Naruto is somehow transported to the world of Highschool DxD. He could use his ninja skills and chakra in the new world, maybe even teach some of the characters there a thing or two about combat. For example, he could show Issei how to better control his power using chakra control techniques.
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.
Yes, there are likely some good ones. You can start by looking on popular fanfiction websites like FanFiction.net or Archive of Our Own. Check the reviews and ratings of the stories to find ones that are well - received by other fans.
One possible fanfiction could involve a crossover where the characters from Highschool DxD and Naruto meet in a unique world. Yasaka, being a powerful figure in the Highschool DxD universe, might interact with Naruto characters. For example, she could form an alliance with Naruto to fight against a common enemy that somehow threatens both of their worlds. Maybe a group of rogue ninjas from Naruto's world team up with some rogue devils from Highschool DxD.
One possible fanfiction could be about a crossover where the characters from Highschool DxD and Naruto are transported to a world where they meet Gabriel. Maybe they team up to fight a common enemy. For example, the devils from Highschool DxD and the ninjas from Naruto could combine their powers under Gabriel's guidance to defeat an ancient evil that threatens all three of their realms.
In a Highschool DxD - Naruto crossover fanfiction with Ophis, she could form an alliance with some of the Akatsuki members. They might be interested in her power and knowledge. Ophis could use this opportunity to learn about the unique chakra system in Naruto. This could lead to a series of battles and power - up scenarios as she tries to adapt to this new world and the Akatsuki tries to use her for their own goals.
There could well be. Fanfiction writers often like to explore crossovers and unique concepts. However, not all fanfic writers might be interested in combining Naruto with 'Highschool DxD' in a certain way, so there are likely to be some that fit the 'Naruto not a devil highschool dxd fanfiction' idea. You might have to dig a bit through different fanfic archives to locate them.
In some Highschool DxD and Naruto crossover fanfictions, Naruto might be depicted as a god - like figure. This could be due to his extremely powerful abilities in the Naruto universe, such as his vast chakra reserves, multiple jutsu, and his status as a hero in his own world. Writers may take these aspects and amplify them in the Highschool DxD setting, where the power levels and the concept of beings with god - like powers already exist. So, it's possible for Naruto to be seen as a god in such fanfictions.
In such a fanfiction, it could be that Issei is bashed because he represents a different kind of hero compared to what Naruto stands for. Naruto is all about self - sacrifice and believing in others no matter what, while Issei is more about his own desires and power - seeking in a way. So when these two worlds collide in the fanfic, Issei might be made to look bad in comparison. Maybe the story has Naruto characters like Sasuke or Kakashi giving Issei a hard time because they don't approve of his behavior.
Yes, there are some interesting ones. You can check out fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'rikudou naruto highschool dxd' and you'll likely find a variety of stories with different takes on combining the elements of Naruto and High School DxD.