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.
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.
Alucard could fit as a powerful outsider. His vampiric abilities like super strength, speed, and the ability to turn into mist or a bat would be very different from normal wizard magic. He could be a sort of anti - hero, helping Harry when it suits his own goals. For example, if there was a dark wizard using blood magic in a way that threatened Alucard's existence too.
The character interactions are also very distinct. Harry is a young wizard who has grown up in a world of rules and order, while Alucard is a centuries - old, more or less amoral being. Their conversations and the way they view the world around them are really interesting to read. For instance, Alucard might see the Hogwarts houses as something completely different from what they are meant to be in the original series, and his views can challenge Harry's understanding of his own world.
Harry would likely be cautious at first. Alucard is a very different kind of being compared to the wizards he knows. Alucard, on the other hand, might be intrigued by Harry's magic. He could start by testing Harry's limits. But as they get to know each other, they might find common ground in their fight against evil. Harry could learn some of Alucard's more ruthless ways of dealing with enemies, while Alucard could understand the importance of friendship and loyalty from Harry and his friends.
A common theme is the clash and eventual harmony of different power systems. Harry has his wizard magic from the Potterverse, and Alucard has his vampiric abilities. Their coming together often involves exploring how these powers interact. Another theme is the idea of redemption or transformation. Alucard, being a vampire, might be seen as a dark character, and through his relationship with Harry, he could experience a change.
There might be some. You could start by checking fanfiction websites like Archive of Our Own. Just search for 'alucard harry potter slash' and browse through the results. However, keep in mind that the quality can vary greatly.
Common themes often include the struggle between light and dark. Harry is typically associated with the light side in the Potterverse, while Alucard has a more ambiguous moral standing. There could also be themes of redemption as they influence each other. For example, Alucard might be influenced by Harry's sense of justice and Harry might come to understand the more complex nature of good and evil through Alucard. Additionally, friendship or a deeper relationship might be a theme as they learn to trust and rely on each other in the fan - created scenarios.
One interesting crossover could be a scenario where Alucard uses his vampiric powers to assist Harry in a battle against Voldemort. Maybe Alucard's super strength and ability to transform could give Harry an edge in a difficult fight.
In fanfiction, Harry's magic is more about control and finesse. He can perform complex spells for various purposes. Alucard, on the other hand, has raw physical power. However, some fanfictions might explore the idea of Harry using his magic to enhance Alucard's abilities or vice versa. For instance, Harry could use a spell to make Alucard immune to sunlight for a short time. Alucard could use his speed to help Harry get out of a dangerous magical trap more quickly. It all depends on how the author wants to blend their powers.