One idea could be that Ben Tennyson somehow gets transferred to the world of High School DxD. He has to keep his alien forms a secret while dealing with the devils, angels, and fallen angels in the school. Maybe his Omnitrix could be misinterpreted as some kind of powerful devil device.
A plot could involve the characters from High School DxD mistaking Ben for a new type of devil or supernatural being because of his alien forms. Ben has to navigate this new world while also trying to find a way back home. Meanwhile, the devils in High School DxD might be interested in the technology of the Omnitrix, leading to a conflict where Ben has to protect it from falling into the wrong hands.
Well, Ben could use his alien forms to help out the characters in High School DxD in battles. For example, if there's a fight against a powerful devil, Ben could transform into Four Arms and use his super strength. The characters in DxD would be amazed by his abilities.
Ben and Issei would be an interesting pairing. Ben is used to being a hero with his Omnitrix, and Issei has his own journey of becoming a powerful devil. They could learn from each other's combat styles. Ben could show Issei how to use his alien forms' unique abilities in battle, and Issei could teach Ben about the world of devils and the importance of relationships in his world.
I'm not sure specifically which 'Ben Zobrist High School story' you're referring to. There could be many stories related to a high school named after Ben Zobrist. It might be about the school's founding, its academic achievements, or the unique culture within the school.
The story mainly follows Issei Hyodo, a high school student who gets killed on his first date and is later resurrected as a devil. He then becomes part of the Occult Research Club at his school. There, he gets involved in various battles against other supernatural beings, all while trying to become stronger and also dealing with his new devilish desires and relationships with his female comrades.
Well, there are prequel novels that offer background on some of the characters and events. Also, there are companion novels that explore additional adventures and story arcs within the same world.
In a Naruto and High School DxD fanfiction, there could be a scenario where the protagonists of both stories meet in a neutral dimension. Issei from High School DxD might be intrigued by Naruto's ninja skills and determination. Naruto, in turn, could be curious about Issei's Sacred Gear. They could start training together, sharing their knowledge and skills, and ultimately have to face a common enemy that threatens both their worlds.