Allen Walker and Issei Hyoudou would be an interesting pairing. Allen has his serious and often brooding nature due to his past as an exorcist, while Issei is more of a pervy and hot - blooded character. Their interactions would be full of contrasts. Another good pairing could be Kanda Yuu and Rias Gremory. Kanda's cold and aloof personality would clash with Rias' more diplomatic and kind - hearted nature. It would be fascinating to see how they deal with each other.
A pairing between Lenalee Lee and Asia Argento would be really sweet. Lenalee is a strong and compassionate exorcist, and Asia is a kind - hearted and gentle character in Highschool DxD. They could bond over their shared sense of kindness and perhaps help each other out in different situations. And then there's the pairing of Komui Lee and Sirzechs Lucifer. Komui's wacky and over - the - top personality when it comes to Lenalee could be really funny when contrasted with Sirzechs' calm and authoritative presence.
One idea could be the exorcists from D Gray - Man ending up in the world of Highschool DxD. They might initially be mistaken for devils or angels due to their strange powers. For example, Allen Walker's cursed eye could be seen as a very unique and perhaps threatening power. Another plot idea could involve the search for the Innocence in the Highschool DxD world. Since both worlds have different forms of power sources, it would be interesting to see how the Innocence interacts with the Sacred Gears. Maybe a character with a Sacred Gear could also be a potential host for the Innocence, creating a whole new dynamic.
Allen Walker and Natsu Dragneel would make an interesting pairing. Allen has his serious and brooding nature due to his past as an Exorcist, while Natsu is hot - headed and impulsive. They could learn a lot from each other. Allen could teach Natsu about the importance of self - control in a fight, and Natsu could show Allen how to have more fun and not be so burdened by his responsibilities all the time.
Ichigo and Akeno could also be an exciting pairing. Akeno has her own unique powers and a mysterious side. Ichigo's straightforwardness and strong moral code could contrast with Akeno's more complex nature. They could work together in battles, with Ichigo providing the brute force and Akeno using her strategic and powerful attacks.
Ichigo and Rias would be a very interesting pairing. Ichigo is a powerful and determined fighter, and Rias is a strong - willed Devil. Their personalities could clash at first, but then they might find common ground in their leadership roles and their desire to protect their respective groups.
Akira and Giorno would make an interesting pairing. Akira has his leadership skills and the ability to use Personas, while Giorno has his determination and powerful Stand, Gold Experience. They could learn from each other's sense of justice and different ways of achieving their goals. Akira could teach Giorno about the power of the collective, as the Phantom Thieves work as a team, and Giorno could show Akira how to be more assertive and decisive in his actions.
Lavi and Edward Elric. Lavi is always curious and loves to explore different things, which is similar to Edward's thirst for knowledge. They could bond over their shared love of books (since Lavi is a Bookman) and also their quests for the truth. Edward could help Lavi understand more about alchemy, while Lavi could introduce Edward to the world of Innocence and exorcism.
One possible scenario in this crossover fanfiction could be the characters from D Gray - Man having to adapt to the unique supernatural environment of High School DxD. For example, Allen Walker might find himself in the middle of a battle between devils and angels in the High School DxD world. His Innocence could be perceived in different ways by the various factions there.
Blake Belladonna and Koneko Toujou. Both are strong female characters with a bit of a mysterious side. Blake's Faunus heritage and her experience with the White Fang could be something that Koneko, with her Nekomata powers, would be interested in. They could bond over their similarities and differences, and perhaps team up in battles against common foes.
Lavi and Ron Weasley could be an amazing pairing. Lavi's laid - back yet observant nature would contrast well with Ron's more hot - headed and loyal personality. They could get into all sorts of adventures together, maybe even accidentally stumbling upon a hidden connection between the two worlds.
Papyrus and Beast would also make for a great pairing. Papyrus is full of enthusiasm and always wants to do the right thing in Glitchtale. Beast is highly intelligent and has his own moral code. Papyrus could learn a lot from Beast's knowledge, and Beast could be inspired by Papyrus' unwavering optimism. They could work together on scientific projects in the X - Men's labs, with Papyrus bringing his unique perspective and Beast his scientific expertise.