In the fanfiction, Goku could start as a mystery student. His power level would be off the charts compared to the others. He might get involved in the power struggles between the different factions like the devils, angels, and fallen angels. Since he has a pure heart, he could try to bring peace among them. His Saiyan appetite would also be a fun aspect, as he'd probably devour all the food in the school cafeteria.
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.
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.
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.
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.
Ichigo, being godlike, would likely be at the top of the power structure. His Bankai and Hollow powers combined would make him extremely formidable. He could easily overpower most of the devils, angels, and fallen angels in terms of raw strength. His speed and combat experience from fighting Hollows and Soul Reapers would also give him an edge in battles.
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.
Goku's powers in a High School DxD fanfiction would be a game - changer. His ki attacks could be on a level that could potentially destroy entire areas in the DxD universe. His martial arts skills are also top - notch. In a fight, he would use his speed and agility to dodge attacks and then counter with his powerful punches and kicks. His transformation abilities, like Super Saiyan, would be a shock to the characters in DxD. They might not have any means to counter such a huge boost in power.
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.
Well, Goku's extreme power level could make him a sort of legend in the Naruto fanfiction world. His Saiyan abilities like the Kamehameha and Super Saiyan forms would be completely foreign to the ninjas. He might be seen as an otherworldly being, and his presence could disrupt the power balance. Maybe he'd come to the Naruto world seeking a new challenge, or perhaps he was accidentally transported there.
He could fit as a powerful outsider. His power level is extremely high with Mugetsu, so he'd be a force to be reckoned with. Maybe he'd be seen as a wildcard by the different groups in DxD.