Well, such a fanfic could be really interesting. It might involve a character who has the abilities or traits from both 'High School DxD' and 'Naruto' universes and is leading the yokai. Maybe this leader could use the ninjutsu from 'Naruto' while also having the devilish powers from 'High School DxD' to rule over the yokai. For example, they could use shadow clones to patrol the yokai territory and at the same time use some sort of demonic charm to keep the yokai in line.
In this fanfic, Naruto as the leader of Youkai in the High School DxD setting could bring a new dynamic. He may introduce concepts from the ninja world like chakra training to the youkai. This could help the youkai become stronger and more unified. Maybe he forms an alliance with the devils in High School DxD, using his leadership skills to broker peace between the two groups, which were previously at odds.
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.
A crossover fanfic could explore a leadership where the leader of yokai has to adapt to the different cultures of 'Naruto' and 'High School DxD'. In 'Naruto', loyalty is often based on shared values and a sense of community. In 'High School DxD', it can be more about power and personal charisma. The leader of yokai would need to find a balance. They could introduce concepts like ninja training to the yokai from 'Naruto' to make them stronger, while also using the more modern and flashy elements from 'High School DxD' to make the yokai more appealing to other factions in both universes. This would help in establishing their leadership over the yokai.
One way would be through power systems. Naruto's chakra could be related to the magic or power in High School DxD. The fox yokai part could be used to explain some of the more mysterious powers. For example, Naruto's fox - like speed and strength could be seen as yokai - like abilities in the High School DxD world.
Perhaps Naruto earns the position through combat. He could defeat a powerful and corrupt youkai leader in a fair fight, and the other youkai, impressed by his strength and honor, would then recognize him as their new leader.
One idea could be to create a fanfic where Naruto is somehow transported to the world of High School DxD. He could bring his unique ninja skills and chakra system. Maybe he teams up with Issei to fight against a common enemy. For example, a powerful devil or fallen angel that threatens both the ninja world and the DxD universe.
He could be a new type of threat or ally in the DxD world. Since Naruto has such powerful abilities, the fallen angels might see him as a potential weapon or a hindrance to their plans.
Well, in this fanfic scenario, Naruto's ninja skills could be a huge asset in the High School DxD world. He might introduce new combat styles and strategies. For example, his shadow clone jutsu could be used in various battles or for pranks. Also, his strong sense of justice would likely influence Rias and her peerage. He could help them make more morally upright decisions, and his experience with facing powerful enemies in the Naruto universe would give them new perspectives on handling threats in their own world.
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.
In this fanfic, Naruto's unique abilities like his shadow clones and Rasengan could be combined with the magic and powers in the DxD universe. For example, a fallen angel might be interested in Naruto's chakra and try to use it for their own purposes. Naruto, being the hero he is, would not let that happen and would start a conflict that could lead to an epic adventure.