One possible fanfic could be about Naruto being transferred to the High School DxD universe and his encounter with the Juubi there. Maybe he has to team up with the characters from High School DxD to deal with the threat of the Juubi. For example, Naruto's unique abilities like the Rasengan and Shadow Clone Jutsu could be a great asset in battles within this new universe.
Naruto might also interact with the Juubi on a more strategic level. He could plan with the characters from High School DxD to contain the Juubi first. For example, using the barriers and spells available in the DxD world along with his own shadow clone jutsu to surround the Juubi. Then, they could work on finding a more permanent solution, like using some ancient magic from the DxD universe combined with Naruto's sealing jutsu.
Well, if Naruto Juubi was in High School DxD fanfiction, the storyline would change drastically. For one, the power dynamics would be completely different. Naruto Juubi is extremely powerful, and in the High School DxD world which already has a complex power system, it would disrupt the existing balance. The characters in High School DxD would have to adapt to this new, overpowering force. Maybe some would try to ally with it, while others would see it as a threat. Also, the cultural and personality differences between the Naruto universe and High School DxD would create interesting interactions. Naruto Juubi's values from the Naruto world might clash or blend with the more modern and somewhat hedonistic values of the High School DxD characters.
One way could be through the power system. The EMS (Eternal Mangekyou Sharingan) from Naruto could be a unique power that a character in the High School DxD world acquires. Maybe a transfer student from a hidden ninja village arrives at the high school and has to keep their EMS a secret while dealing with the devils and angels in the school. This could lead to some interesting battles and interactions as the powers of the EMS, like the ability to use powerful jutsus, contrast with the magic and abilities of the High School DxD characters.
It might be a story where the concepts from Naruto and Highschool DxD are mashed up. For instance, the power systems could be combined. Naruto's chakra and the magic or sacred gears in Highschool DxD could interact in interesting ways. And perhaps the characters from both series form new alliances or rivalries based on their different abilities and goals.
A fanfic of this nature could explore different themes. One theme could be the clash between different power systems, that is, the ninjutsu from Naruto and the magic in High School DxD. The primordial god connection could act as a bridge or a source of conflict. Another theme could be about Naruto's journey of self - discovery in this new and strange world. He might have to adapt to the different social and power structures in High School DxD while also coming to terms with his new role as someone related to a primordial god.
One great 'Naruto - High School DxD' fanfic is 'Naruto in the World of High School DxD'. In this fanfic, Naruto is somehow transported to the world of High School DxD. It's interesting to see how his ninja skills and values from the Naruto world interact with the supernatural and often chaotic world of High School DxD. The author does a good job of integrating Naruto's character traits into the new setting, creating a unique and engaging story.
Well, let's consider Kiba from High School DxD. He's a proud devil with his own set of skills. If Naruto Juubi was in the fanfiction, Kiba might be a bit jealous of its power at first. He might try to prove himself by competing with Naruto Juubi in some way. Xenovia, with her strong sense of justice, could have an interesting relationship. She might see Naruto Juubi as an unknown entity and be on guard, but also be curious to see if it has good intentions. Naruto Juubi, coming from the Naruto universe, might be confused by the different social norms in High School DxD. This could lead to some comical interactions with characters like Asia, who is very kind - she might try to befriend Naruto Juubi and explain the ways of their world.
One possible fanfic could be about an angel who gets trapped in the Naruto world and has to adapt to its ninja ways while still retaining some of the powers and characteristics from the DxD universe. For example, the angel might use its holy powers in a new way to fight against the akatsuki.
He could be seen as a mysterious figure at first. Given his different appearance and abilities compared to the devils, angels, and fallen angels in the DxD world. Naruto might initially be a target of suspicion, but as he shows his good heart and helps out in various situations, like protecting the school from an attack, he would gradually be accepted. He could also have some interesting interactions with the magic and power systems in the DxD universe, maybe even finding a way to combine his chakra with their powers.
One possibility could be a story where Naruto, with his unique abilities from his own world, enters the High School DxD universe and meets Kuroka. In this harem fanfiction, Naruto's kind heart and strong power might attract Kuroka and other characters. They could go on adventures together, with Naruto's ninja skills being a novelty in the DxD world. And his determination to protect could make him a central figure in the harem.