He could fit in as a new type of supernatural being. Since he has god - like powers, he might be seen as a threat at first. But then, as the story progresses, he could form alliances. For example, he could team up with the devils against a common enemy. His abilities like instant teleportation (using techniques like Flying Thunder God) would be very useful in the battles in the Highschool DxD universe.
He could fit in as a super - powerful outsider. His Juubi powers would make him stand out, but his Naruto - like personality of being friendly and determined would help him make friends. He might use his powers to help the school during times of crisis, just like he did in his own world.
Goku would fit in as a super - powerful outsider. His physical strength and combat skills are far beyond what the normal characters in Highschool DxD are used to. He could become a sort of protector for the school, using his powers to fend off any threats that come their way. His energy - sensing ability would give him an edge in detecting hidden enemies.
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.
Naruto would probably be very friendly and curious. He'd be excited to meet all the different types of beings in the Highschool DxD world. He might start by trying to make friends with Issei, sharing his stories about his own battles and adventures in his world.
Naruto's abilities would bring a whole new dynamic to the Highschool DxD universe. His ability to use chakra to walk on walls and water could give him an advantage in certain terrains or situations. In battles, his ability to sense chakra could help him detect hidden enemies. Also, his summoning jutsu could call upon powerful creatures from the Naruto universe. If these creatures were introduced into the Highschool DxD world, they could change the balance of power. And his various transformation jutsu could be used for disguise or to gain temporary boosts in power.
He would fit in as a unique and powerful character. His abilities would make him a force to be reckoned with. He could use his speed and strength to compete with the devils and other supernatural beings in the DxD world.
Some Naruto characters might also form unique relationships with Highschool DxD characters. For example, Sakura could become friends with some of the female characters in Highschool DxD and share her medical knowledge. Or Sasuke could be a rival to some of the strong male characters in the Highschool DxD universe, leading to intense battles and character development.
Saber could fit in as a powerful ally. Her noble phantasms and combat abilities would make her a force to be reckoned with. In a world full of supernatural beings like Highschool DxD, she would be another strong addition. She might be seen as a sort of mysterious figure that both the devils and the angels would be curious about.
Sasuke can fit in as a powerful outsider. His skills and abilities make him a force to be reckoned with. For example, his Sharingan can give him an edge in combat and in detecting hidden motives of characters in the DxD world.
His speed would likely be enhanced. In the DxD universe, there are fast - moving opponents like the devils and angels. Naruto, already known for his incredible speed in his own world, would need to adapt and become even faster. His rasengan, for instance, might be modified to be more effective against the magical defenses of DxD characters.