Yes, there are quite a few. You can check fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'King Naruto Highschool DxD' on their platforms and you'll find a variety of stories with different takes on the concept.
In some fanfictions, the Ice King's ice powers might be combined with Naruto's ninja skills in the DxD setting. Maybe Naruto has to team up with characters from DxD to stop the Ice King from freezing the entire DxD world. It could explore how the different power systems interact, like Naruto's chakra versus the magic in DxD and the Ice King's ice magic. There are often fanfictions that focus on these kinds of power - based interactions and character growth within the new and combined universes.
The combination of two very different universes. Naruto's world is full of ninjas and chakra, while Highschool DxD has its own unique supernatural elements like devils, angels, and fallen angels. When you mix Naruto as a king into Highschool DxD, it creates a whole new set of story possibilities.
It has the potential to be popular. The idea of Naruto being the 'king' in a High School DxD fanfiction is an interesting concept. 'Naruto' has its own rich lore and a large fan base, and 'High School DxD' also has a dedicated following. When combined, it can create a lot of interesting scenarios. For example, Naruto could bring his sense of justice and powerful ninja abilities to the somewhat chaotic world of High School DxD, which would be appealing to fans who like to see new takes on their favorite characters and universes.
Naruto's strong will and his never - give - up attitude would also play a major role. In a fanfiction, he might be the one to inspire the DxD characters to not be afraid of the Ice King's power. His experience in fighting powerful enemies in his own world would give him an edge in strategizing against the Ice King in the DxD setting. He could also potentially teach the DxD characters some of his ninja skills, which could then be modified to work with their own magic, creating new and unique combat techniques.
The most interesting aspect could be the character interactions. Naruto, with his positive and determined attitude, would interact with the characters from High School DxD. His ninja skills and abilities would also add a new dynamic to the story. For example, his shadow clone jutsu could be used in some really creative ways in the High School DxD setting, like in battles or even in school pranks.
One possible interesting plot could be that Naruto, with his unique ninja skills, gets transferred to High School DxD's world. He might initially struggle to adapt to the different rules and magic there. For example, he could mistake a devil's magic for some kind of new jutsu. Then, he could end up teaming with Issei and his group to fight a common enemy that threatens both the ninja world and the world of High School DxD. Maybe an ancient evil that wants to use the power of both chakras and devil magic for its own dark purposes.
There probably is. A lot of fanfiction platforms are filled with creative crossovers. Given the popularity of Naruto and High School DxD, some fans might be intrigued by the idea of Naruto being in the Dragon DxD universe. They could explore how Naruto's abilities would interact with the unique magic and supernatural elements in the Dragon DxD world, like how his ninja skills would fare against the devils and angels in that setting.
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.
Yes, there might be such fanfictions out there. Fanfiction writers often create crossovers where they put characters from different universes like Naruto and High School DxD together and come up with various scenarios, including ones where Naruto could potentially 'kill' a character from the DxD universe. However, the quality and nature of these fanfictions can vary greatly.