Well, it could be about the Son of Amaterasu having to deal with the power struggles in the High School DxD world. Maybe he has some unique abilities inherited from his mother that make him a target or a valuable ally.
He might have the ability to control some form of divine light, which could be used for both offensive and defensive purposes. This could be different from other characters' abilities in High School DxD as it would have a more divine origin.
Well, in this fanfiction, Naruto's origin as the son of Amaterasu could lead to a story where he is initially shunned by some in the DxD world because of his strange powers. But as he proves himself in battles and shows his kind heart, he starts to gain allies. His journey could also be about uncovering the secrets of his mother Amaterasu and how that relates to the overall balance of power in the DxD universe. Maybe he has to face an ancient evil that only his combined ninja and divine powers can defeat.
One interesting plot could be Issei exploring his new divine heritage. Since Amaterasu is a powerful goddess in Japanese mythology, he might discover new powers related to the sun. For example, he could have the ability to emit intense heat or blinding light, which would be a great addition to his combat skills in the Highschool DxD universe. Another plot could involve the reactions of his friends and enemies to this new revelation. His friends might be in awe or a bit jealous, while his enemies could see him as an even greater threat.
One possible plot is that Gilgamesh views the High School DxD setting as beneath him at first. But as he gets to know the characters like Issei and Rias, he starts to see the value in their struggles. He could then use his vast resources and power to help them in their fight against stronger enemies, all while maintaining his haughty and kingly demeanor.
Naruto in this fanfiction would likely have a different sense of self - identity. He's used to being a ninja from Konoha, but now as the son of Amaterasu, he has a whole new heritage to grapple with. He might be more confident in his abilities, as he has this divine blood in him. Also, his relationships with others could change. For instance, he might be more cautious around devils, given his divine origin, but also be more curious about their ways compared to his original Naruto self.
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.
Well, in some High School DxD fanfictions, the OC might be considered Satan's son to create a really powerful and unique character. It could be for the sake of having a character with a dark and mysterious origin that can bring in a lot of interesting plot twists. Maybe the author wants to explore the idea of a character with demonic powers and a connection to the most powerful figure in the underworld, Satan.
The story mainly follows Issei Hyodo, a high school student who gets killed on his first date and is later resurrected as a devil. He then becomes part of the Occult Research Club at his school. There, he gets involved in various battles against other supernatural beings, all while trying to become stronger and also dealing with his new devilish desires and relationships with his female comrades.
Well, one possibility could be that Naruto has extraordinary powers due to his divine heritage. He might be able to control both the fire of Amaterasu in a unique way and also possess some of Zeus' lightning or godly strength. Maybe he has to face enemies who are threatened by his existence and his combined powers make him a target. He could also struggle with his identity, being part of two very different mythologies.
Perhaps Issei discovers that his connection to Great Red gives him the ability to travel to different realms more easily. This could lead to him exploring new places, making new allies and enemies, and learning more about his true nature. It could also involve him having to protect these realms from threats that only he, as the son of Great Red, can face.