What are some interesting plot ideas for Hellsing Alexandee crossover fanfiction?

First, do your research on both Hellsing and Alexandee. Know the characters, the settings, and the rules of each universe. This will help you create a more believable crossover.

One idea could be to have Alucard from Hellsing meet the vampires in Twilight. Maybe Alucard would be amused by their 'tame' nature compared to his own blood - thirsty self. He could show them what a real vampire is capable of in a fight.

One idea could be a crossover with 'Berserk'. The dark and gritty worlds of both could blend well. The vampires from Hellsing could interact with the Apostles from Berserk, leading to epic battles. Another could be a crossover with 'Fullmetal Alchemist'. Imagine the alchemists trying to understand the nature of the vampires in Hellsing. Maybe they'd try to find a way to use alchemy on them.

Another possibility is a crossover with 'Tokyo Ghoul'. The ghouls' unique abilities and the vampire - hunter theme of 'Hellsing' could make for a really intense and dark fanfiction. The struggle between the two species in a shared world would be full of drama and action.

One idea could be that the wizards in the Harry Potter world discover the existence of the Hellsing Organization. Maybe Harry and his friends end up teaming up with Alucard to fight a common dark magic threat that is beyond what the wizarding world alone can handle.

One idea could be that the Addams Family, being the strange and macabre family they are, somehow get involved in the vampire - hunting activities of the Hellsing Organization. Maybe they see the vampires as kindred spirits in a way, but also recognize the danger they pose. Another could be a situation where a member of the Addams Family becomes a target of the vampires in the Hellsing universe, and the Hellsing crew has to work with the family to protect them.

One plot idea could be Naruto being transported to the Hellsing universe and having to deal with the vampires there using his ninja skills. He might form an alliance with the Hellsing Organization and help them fight against a new, powerful vampire threat.

A plot could involve a powerful ancient evil that has been sealed away in both universes. The seal is weakening in both the Hellsing world and the Supernatural world simultaneously. So, the protagonists from both sides must combine their knowledge and resources. Alucard from Hellsing could bring his immense power and immortality, while Sam and Dean Winchester could offer their knowledge of a wide variety of American - based supernatural entities and their hunting skills.

Maybe an OC devil who was once a human and was turned into a devil against their will. They could struggle with their new identity while still having some human emotions, which would create complex relationships with the Hellsing characters.

One possible plot could be that Naruto and his team are sent to the Hellsing universe on a mission. They encounter Alucard and his group. Naruto, with his ninja skills and strong will, might initially be seen as a threat by the Hellsing crew. But as they learn about his world and his fight for peace, they start to work together. Maybe Naruto tries to understand Alucard's vampiric nature and in turn, Alucard is intrigued by Naruto's chakra and jutsu. Together, they could face a new threat that is endangering both their universes.