One idea could be that the characters from Highschool DxD end up in the Hellsing universe. Maybe Issei and his friends are mistaken for new types of vampires due to their devil powers. They then have to team up with the Hellsing organization to clear their names and also fight against a common enemy that is threatening both the devil and human worlds in this combined universe.
The exploration of morality is also a big theme. When Hellsing crosses with a more 'pure - hearted' universe like 'My Little Pony' (in some very creative crossovers), it forces the characters to re - evaluate their views on good and evil. Alucard's brutal nature might seem out of place in the colorful world of ponies, and this contrast creates interesting moral discussions.
In these crossovers, a common theme is the struggle between good and evil. Walter is often in a position where he has to decide which side he truly stands on in the Hellsing world. Another theme is the concept of time. Sometimes the fanfictions play with the idea of time, like Walter being sent back in time within the Hellsing universe or having to deal with time - related anomalies. And friendship is also a theme. His relationships with the characters in Hellsing, whether they develop into true friendships or remain strained, are often explored in these fanfictions.
There are quite a few. One interesting aspect is seeing how the moral and ethical concepts from both 'Bleach' and 'Hellsing' clash or blend. The storylines often involve the characters from both series having to team up against a common enemy that is even more powerful than what they usually face in their own respective worlds.
One interesting concept could be the combination of Hellsing's dark and gritty vampire lore with RWBY's unique world of Huntsmen and Grimm. For example, seeing how the powerful vampires from Hellsing would interact with the various characters in RWBY, like Ruby and her team. Maybe the vampires would be seen as a new type of Grimm by the RWBY characters at first, leading to some initial confusion and intense battles.
Obviously, Hans would be one of the main characters. He would bring his own set of characteristics and abilities into the Hellsing universe. Alucard is also likely to be a main character as he is one of the central figures in Hellsing. His overpowered nature and complex personality would create interesting interactions with Hans.
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.
One interesting concept could be the exploration of different power dynamics. For example, how Hans' unique abilities might interact with the supernatural elements in Hellsing. Maybe his skills could be enhanced or modified in the Hellsing universe, leading to new and unexpected storylines.
Sure. One great 'hellsing captain crossover fanfiction' is 'Hellsing and Captain America's Adventure'. It combines the dark and gritty world of Hellsing with the heroic and patriotic elements of Captain America. The story often has them team up against a common enemy that threatens both their worlds.
The plot should blend the two universes well. A good 'hellsing captain crossover fanfiction' will find a way to incorporate the unique elements of both Hellsing's dark and supernatural world and the Captain's world, whether it's military or heroic in nature. For instance, it might have a story where a new threat emerges that can only be defeated by combining the strengths of both sides, like using the Captain's leadership skills along with Hellsing's knowledge of the undead.