Well, in 'harry x draco vampire fanfiction', a frequent theme is power dynamics. As a vampire, Draco might have certain powers that change the balance in his relationship with Harry. Another is the exploration of the unknown. Vampirism is something new and different in the Harry Potter universe, so the stories often explore how Harry and Draco deal with this unknown element. And of course, there's the theme of loyalty. Their loyalty to each other is tested as they face the challenges of Draco being a vampire.
A sense of mystery and the unknown is a big part of it. Vampires are associated with mystery, and in these fanfics, that mystery is often transferred to the relationship between Draco and Harry. How did Draco become a vampire? What are the rules and secrets of his vampiric existence? And how does Harry deal with all these new elements? These are all questions that the fanfictions might explore, making the overall theme of mystery a significant part of the genre.
One popular 'harry x draco vampire fanfiction' is 'Blood Ties'. It delves into an alternate universe where Draco is turned into a vampire and his complex relationship with Harry unfolds. Another is 'Vampiric Entanglement' which has a really interesting take on how the magical world deals with vampires in the context of their relationship.
One popular plotline is the struggle between Draco's vampiric nature and his feelings for Harry. For example, he might be torn between his thirst for blood and his love for Harry. Another plotline could involve them facing the wizarding world's prejudice against vampires together. They have to prove that their relationship can work despite Draco being a vampire.
You can start by looking on fanfiction platforms like Archive of Our Own (AO3). It has a large collection of fanfics in various categories, including Draco x Harry vampire-themed ones. Just use the search function and type in relevant keywords.
Some authors depict their relationship as a slow - burn one. At first, Harry might be wary of Draco because of his vampiric side. But as they interact more, they start to understand each other better. Draco could use his vampire senses to protect Harry, and Harry could offer Draco the acceptance he's never had. Their relationship might also be shown as a forbidden love in the wizarding world, which adds to the allure.
One idea could be that a vampire infiltrates Hogwarts and Snape, Draco, and Harry have to put aside their differences to deal with it. Maybe the vampire has a special connection to the dark arts, which Snape is intrigued by while Draco is initially tempted by the vampire's power, and Harry is just determined to protect the school.
I'd recommend 'Draco Malfoy and the Mortifying Ordeal of Being in Love'. This fanfic does an amazing job of portraying Draco's internal struggle with his feelings for Harry. It's full of humor and heart - warming moments, and the author has a great way of making the relationship seem both believable and exciting.
One great 'Draco x Harry fanfic' is 'All Our Secrets Laid Bare'. It delves deep into their relationship, exploring how they might overcome their initial enmity in the Hogwarts setting. It has a really engaging plot that keeps you hooked from start to finish.
There's also 'Harry and the Vampire Prince'. This one stands out because it shows how the wizarding society reacts to Draco being a vampire and his relationship with Harry. It has a unique plot where they have to face many challenges together, both from within Hogwarts and from the outside magical community. It's a story that really makes you think about acceptance and love in a different context.