It is indeed common. The allure of the vampire, despite being the hunted, and the hunter's own humanity that allows for love to bloom creates a complex and interesting dynamic. This kind of relationship in these novels often explores themes of acceptance, sacrifice, and the power of love to overcome differences. It also provides a fresh take on the traditional vampire - human relationship, making the story more engaging and multi - faceted.
First, you need to study the source materials. Know the personalities, abilities, and backstories of both D and Van Helsing. For example, D is a dhampir with superhuman strength and speed, and Van Helsing is an experienced vampire hunter with a vast knowledge of vampire lore. Then, come up with an interesting plot. It could be a new threat that only they can defeat together.
You might consider giving him some space to explore the manga on his own and then discussing it together. Sharing your enthusiasm and showing how it brings you joy could potentially get him on your side.
Van Helsing from 'Dracula' is very iconic. He's a knowledgeable and fearless vampire hunter, using his medical and occult knowledge to combat Dracula. Another is Buffy from 'Buffy the Vampire Slayer' series. She's a modern - day slayer, a girl with super strength and skills to take on vampires. And D from 'The Vampire Hunter D' series, with his mysterious dhampir nature and his cool sword - fighting skills against vampires.