There might be a friend of Alucard's son. This friend could be a normal human who has no idea about Alucard's true nature. He could be the one who encourages Alucard's son to seek out his father and be there for him during the difficult process of getting to know Alucard.
In this fanfic, Alucard meeting his son could be a very emotional event. His son could be a product of a long - forgotten relationship. At the meeting, Alucard might see a lot of himself in his son, both in appearance and in personality. They could have a tense conversation at first, with Alucard trying to figure out what his son wants from him. As time passes, they might develop a mutual respect. His son could teach Alucard things about humanity and family that he had long forgotten. And Alucard could in turn pass on his skills and knowledge to his son, leading to a new chapter in both of their lives.
Obviously Naruto, as the title implies he is the main focus. And since he is the son of Alucard, Alucard himself might be a major character, either in flashbacks or as a guiding force in Naruto's life.
Well, it could be about Naruto having some of Alucard's powers. Maybe he has enhanced strength and speed like Alucard. And he could use these powers to protect Konoha in a new and unique way.
Kakashi could also play a major role. He has a wealth of knowledge and experience, and could guide the son in his training. And then there's Tsunade. As the Hokage, she might be involved in decisions regarding the son's presence in the village and could also offer her medical expertise when the son gets injured during his adventures. There could also be some of the tailed beasts as characters, as they have their own powers and could interact with the son in various ways.
It could be an ancient and powerful vampire who has awakened from a long slumber. This vampire might see Alucard and Seras as a threat to his plans of ruling over all vampires.
The plot could start with Harry always feeling different from the other wizards, having some strange instincts. As he uncovers the truth about being Alucard's son, he could be drawn into a world that combines the dark, gothic elements of Alucard's world with the magic of the Harry Potter universe. Maybe there are ancient prophecies related to his dual heritage that he has to fulfill, all while facing the usual enemies from the Potter series, but with a new and more complex set of powers at his disposal.
Well, it could be an original character who was hidden away from Magneto for some reason. Maybe a human - mutant hybrid that Magneto didn't know about. This son could have powers that are not fully developed at first, and through his encounter with Magneto, he starts to discover and master his abilities. He could be a character who was raised by a family that was against Magneto's ideas, so there's a lot of conflict when they meet.
Yes, there are some out there. However, it's a rather unique crossover concept. You can try searching on fanfiction - specific websites like Archive of Our Own or FanFiction.net. Just type in the title 'Harry Potter son of Alucard' in their search bars and you might find some interesting stories.
Well, it could be about Alucard and Seras teaming up to fight a powerful new vampire threat. Maybe they discover a group of vampires that are trying to take over the city and they use their combined powers to stop them.
There could be a female character, perhaps a healer. She helps Owens when he gets injured during his search. She might also have a special connection to the son in some way, like she was the son's babysitter or something similar. And then there could be the local village people. Some of them are sympathetic to Owens' cause and offer him shelter and food, while others are suspicious of him and his motives, which adds more complexity to the story.