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.
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.
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.
One possible plot could be Naruto discovering his divine heritage. He might gain new powers related to Amaterasu Okami. For example, he could have the ability to control some form of sacred fire or light. This would change his relationship with the other characters. His friends might be in awe or a bit scared at first. His enemies would surely see him as an even greater threat.
The plot could involve Percy traveling to Japan to learn more about his newfound 'parentage'. There, he meets other Japanese demigods or spirits who either help or hinder him. Maybe he discovers a prophecy that only he, as the son of Amaterasu, can fulfill, which has something to do with saving both the Greek and Japanese mythological worlds from a great 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.
Well, the plot could involve Shirou and Artoria being transferred to the High School DxD world. Maybe they would have to deal with the devils, angels, and fallen angels there. Shirou's combat skills and Artoria's power would surely make an impact. They could form alliances or even find themselves in the middle of the three - faction conflict.
The plot could also be centered on a mystery related to their family. The brother of Rias discovers some secrets about their family's past that put them both in danger. He then has to work with Rias to uncover the truth and stop whoever is trying to use their family secrets against them. This could involve battles, political intrigue within the Devil world, and self - discovery for both of them.
One possible plot could be that Natsu, being in the DxD High School setting, is betrayed by someone he considered a close friend. Maybe this friend reveals Natsu's secrets to the enemies in the DxD world. As a result, Natsu has to face new challenges alone, all while trying to figure out how to deal with the betrayal and regain his trust in others.
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.
One idea could be that Superman, with his powers, becomes a sort of protector in the High School DxD world. He could use his super strength to stop any over - the - top fights that break out between the different factions. And his heat vision might come in handy when dealing with some of the more dangerous magical threats that lurk in the shadows of the school.