Alucard from "Hellsing" would be a great addition. His overpowered nature and complex personality would contrast well with D's stoicism. They could have an interesting dynamic, either as allies or enemies depending on the plot.
Selene from "Underworld" would also be a good choice. As a vampire herself, she has her own code and goals. Her encounter with D, a dhampir, could lead to a lot of internal conflict for her. Plus, their fight scenes together would be amazing.
Another option could be Van Helsing from the movie of the same name. He is a classic vampire hunter. He and D could exchange hunting techniques and knowledge. And they could form an alliance when they discover a group of vampires that are planning something really big, like taking over a major city.
Clary Fray would be a great character to include as she is one of the main characters in the Shadow Hunter world. Her skills and determination can add a lot to a crossover story.
Well, if you're doing a crossover with 'Buffy the Vampire Slayer', Buffy herself would be a great addition. Her slayer skills would create an interesting dynamic with the vampires from 'Interview with a Vampire'. Also, Angel from 'Buffy' could be included as he has a similar vampire - with - a - soul situation. Another good character could be Van Helsing from the various Van Helsing stories. His vampire - hunting skills would bring a lot of action to the crossover.
A crossover with "Castlevania" would also be cool. D could find himself in the world of Castlevania, dealing with the various dark creatures there. He might have to navigate the complex politics between the vampires and the humans in that universe.
Definitely a magical gnome. Gnomes are often associated with magic and mischief, and they could interact with the little vampire in fun ways. And an angel character would be great too. The angel could represent the good and the vampire could be on the more 'grey' side of morality, leading to some great character development moments.
A crossover with Bleach could include Ichigo Kurosaki. His Shinigami powers would be a formidable force against the Akuma. He could also offer a different perspective on death and the afterlife compared to what is shown in D.Gray - Man. His hot - tempered nature might sometimes clash with the more reserved Exorcists, but in the end, they would work together to fight the greater evil.
A powerful ancient vampire lord could be the main antagonist. He could be so old and strong that he has knowledge and powers that both D and Van Helsing have never faced before.
The main character is D, a dhampir, half - vampire and half - human. He is a powerful vampire hunter with extraordinary strength and skills.
The Hunter themselves are of course very popular. Their mysterious nature and badass fighting skills make them a central figure in any crossover. They can bring their signature weapons like the Saw Cleaver or the Hunter Axe into new settings.
Yes, there are some really interesting 'Vampire Hunter D Castlevania' fanfictions out there. You can often find them on fanfiction websites. Some might focus on crossovers between the two universes, like having D interact with the characters from Castlevania. Others might explore new storylines inspired by the unique elements of both.