Well, in such a fanfic, it might involve a plot where Queen Lemon is a key to resolving a conflict between the two worlds. The characters from Naruto, like Naruto himself or Sasuke, could interact with the characters from High School DxD. They would have to deal with cultural differences. Naruto's positive attitude might influence the more complex characters in High School DxD, and Queen Lemon could be the catalyst for this interaction.
One possible storyline could be that Queen Lemon is a lost princess from a hidden land in the Naruto world and she ends up in the High School DxD universe. There, she has to find her way back home with the help of the characters from both series. For instance, Issei from High School DxD could use his unique powers to protect her while Naruto teaches her some ninja skills for self - defense.
It could be really exciting. Imagine Naruto's ninja skills combined with the supernatural elements of High School DxD. The fox yokai aspect could add a whole new layer of mystery. Maybe Naruto could be a transfer student in the High School DxD world and his fox - like powers or chakra could be mistaken for some kind of yokai ability. His combat skills would surely make him stand out among the students there.
Well, perhaps she is there to find a powerful artifact hidden in the school. This would bring her into conflict with the different groups in the school, like the devils who also want the artifact. And as she searches, she has to deal with the social and power structures of the school which are very different from her own world.
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 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.
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.
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.
There could be a really interesting fanfiction where the Queen of Blades from StarCraft gets inserted into the High School DxD universe. Maybe she could be a powerful new character in the school, causing all sorts of chaos or perhaps she teams up with the main characters to fight against a common enemy. It all depends on the creativity of the writer.
A 'Naruto in High School DxD' fanfiction could involve Naruto being transferred to the DxD school. He would stand out immediately with his orange jumpsuit. His Rasengan could be a very powerful move against the devils and angels in that universe. And his sense of justice would likely lead him to get involved in all the power struggles and protect the weak, just like he did in his own world.
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.