Definitely include Issei. He's the main character in High School DxD and has his unique abilities with the Boosted Gear. Rias is also a great choice as she is a powerful devil. If you're doing a crossover with 'My Hero Academia', Bakugo could be an interesting addition. His explosive personality and powerful quirk would create some intense interactions with the DxD characters.
In a crossover fanfiction, Akeno from High School DxD would be a great character to include. She has her own charm and powers. If it's a crossover with 'Attack on Titan', Levi could be included. His combat skills and no - nonsense attitude would be a great contrast to the more flamboyant DxD characters. Also, consider Koneko from DxD. Her cat - like abilities and quiet nature could lead to some interesting storylines in a crossover.
When thinking about characters for a high school dxd crossover fanfiction, Asia from High School DxD is an important one. She has a kind heart and her healing abilities. If you cross it with 'Fullmetal Alchemist', Edward Elric could be added. His knowledge of alchemy and his quest for the Philosopher's Stone would mesh well with the DxD world's search for power. And of course, don't forget about Xenovia in DxD. Her sword skills could be useful in many crossovers.
If it's a crossover with 'Tokyo Ghoul', Kaneki would be a great addition. His half - ghoul nature and his kagune abilities would make for some intense battles against the devils in High School DxD. Also, Touka's tsundere - like personality could create some interesting relationships with the characters in DxD.
Issei is an obvious choice. Since he is the main character in the original High School DxD, reincarnating another character in relation to him can create a lot of interesting storylines. For example, a reincarnated character could be his long - lost sister from a past life or a reincarnated hero who is destined to be his rival. Rias is also a great character to include. Her status as a devil and a leader makes her a central figure. A reincarnated character could be a new member of her peerage, bringing in new abilities and a different backstory. Akeno is another one. Her dual - natured personality can add depth to the story when interacting with a reincarnated character. Maybe the reincarnated character helps her come to terms with her past or her darker side.
Well, if you're thinking about a crossover with the Marvel universe, Spider - Man would be a cool character to include. His acrobatic fighting style and his sense of humor would mesh well with the high - school - aged characters in 'the god of high school'. Also, Thor could be interesting. His god - like powers and his noble personality would be a great contrast. And in a crossover with the DC universe, Batman would be a great choice. His detective skills and strategic mind could add a different layer to the story.
Naruto Uzumaki is often a very popular crossover character. His status as a powerful ninja and his unique personality make him stand out. Fans like to see how he would interact with the characters from High School DxD.
Issei from High School DxD is also popular in crossovers. His pervy nature could create some humorous situations when interacting with the more serious Naruto characters. Also, his power as a devil and his ability to boost his power through his perverted desires can be an interesting contrast to the chakra - based powers in Naruto.
One possible fanfiction could be about Naruto characters attending the school in High School DxD. For example, Naruto's positive and determined attitude might clash with the more complex social and power dynamics in the DxD world. He could make new friends or even rivals among the devils, angels, and fallen angels.
One possible fanfiction could be about Naruto characters somehow ending up in the world of High School DxD. Maybe Naruto's skills in combat and his determination would make him a formidable opponent in the battles that often occur in the High School DxD universe. He could form interesting alliances or rivalries with the characters there.
A fanfiction might explore how the power of the Excalibur in High School DxD would interact with Naruto's chakra. Since the Excalibur is a powerful holy weapon, it could have some interesting reactions when in the presence of Naruto's unique chakra, which is different from the magic in the High School DxD world. For example, it could either enhance or nullify certain abilities depending on how the author writes it.
In a Naruto - High School DxD fanfiction, the power levels would be really interesting to explore. Naruto's sage mode and tailed - beast forms are extremely powerful. In the DxD world, there are different power systems like the Sacred Gears. It would be fascinating to see how Naruto's powers interact with the powers of the DxD characters. For example, could his Rasengan be enhanced by a Sacred Gear? Or how would he fare against a devil's magic?
One possible scenario could be that Naruto characters are somehow transported to the world of High School DxD. Naruto's ninjutsu skills would be quite a shock to the devils and angels in that world. For example, Sasuke's Sharingan could give him an edge in battles against the supernatural beings in High School DxD. And Naruto's never - give - up attitude might inspire some of the characters there to face their challenges more bravely.