His divine lineage would likely make Issei more confident. Knowing he has such a powerful mother in Amaterasu, he would feel like he has a greater purpose. This newfound confidence could lead to him being more assertive in battles and in his relationships with other characters.
Begin with a question related to the story. For instance, if it's a story about a bike race they had, you could start with 'Have you ever wondered what it's like to be in a really intense bike race? Well, my son and his friends found out.' This grabs the listeners' attention and makes them curious about the story.
There's a fanfiction where Issei's son has a unique power that sets him apart. In this story, he has to learn to control it while also handling the typical Highschool DxD drama like rivalries and romances. The author does a great job of showing how he struggles with being in his father's shadow at times, but also rises above it in his own way.
I haven't read this particular fanfiction yet, but generally, a fanfiction about the son of Sirzechs in the Highschool DxD universe could be really interesting. It might explore new powers, relationships, and storylines that the original series didn't cover. For example, how the OC would interact with the existing characters like Issei and Rias, and how his heritage as the son of Sirzechs would shape his destiny in the Devil society.
A good place to start is by looking at the most popular ones on major fanfiction platforms. Usually, the ones with the highest ratings or most reviews are worth checking out first.
His relationship with Rias would likely become more complex. She might see him in a new light, both as a powerful being in his own right and also as someone with a great destiny. There could be some tension as she tries to figure out how to interact with him now.
Well, Naruto has a wide range of powerful abilities like his shadow clones, rasengan, and chakra control. In the Highschool DxD universe which is filled with devils, angels, and fallen angels, his powers could be quite unique. His shadow clones could be used for various strategic purposes, like scouting or overwhelming opponents in battles. His rasengan, being a powerful concentrated attack, could be a real threat to the supernatural beings there. And his chakra control might give him an edge in adapting to different situations compared to the more traditional magic - based powers in DxD.
The OC, as the Son of Sparda, could fit in by being a new and powerful entity. He might be initially seen as an outsider, but his powers would quickly draw attention. He could become involved in the power struggles between the different factions in Highschool DxD. For example, the devils might try to recruit him, while the angels might be wary of his presence. His unique abilities would also make him a valuable ally or a fearsome opponent. And in the high school setting, he could be a bit of an enigma to the other students, both human and supernatural.
Romance is also a big theme. Just like in the original Highschool DxD, his son usually has his own love interests. These relationships can be complicated by his status as Issei's son. Sometimes, potential partners are attracted to him because of his family name, and he has to figure out if their feelings are genuine.
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.