Silver Under Nightfall Silver Under Nightfall #1

Full of court intrigue, queer romance, and terrifying monsters—this "deliciously fun" (Sangu Mandanna, author of The Very Secret Society of Irregular Witches) epic fantasy appeals to fans of Samantha Shannon's The Priory of the Orange Tree and the adult animated series Castlevania.
Remy Pendergast is many things: the only son of the Duke of Valenbonne (though his father might wish otherwise), an elite bounty hunter of rogue vampires, and an outcast among his fellow Reapers. His mother was the subject of gossip even before she eloped with a vampire, giving rise to the rumors that Remy is half-vampire himself. Though the kingdom of Aluria barely tolerates him, Remy's father has been shaping him into a weapon to fight for the kingdom at any cost.
When a terrifying new breed of vampire is sighted outside of the city, Remy prepares to investigate alone. But then he encounters the shockingly warmhearted vampire heiress Xiaodan Song and her infuriatingly arrogant fiancé, vampire lord Zidan Malekh, who may hold the key to defeating the creatures—though he knows associating with them won't do his reputation any favors. When he's offered a spot alongside them to find the truth about the mutating virus Rot that's plaguing the kingdom, Remy faces a choice.
It's one he's certain he'll regret.
But as the three face dangerous hardships during their journey, Remy develops fond and complicated feelings for the couple. He begins to question what he holds true about vampires, as well as the story behind his own family legacy. As the Rot continues to spread across the kingdom, Remy must decide where his loyalties lie: with his father and the kingdom he's been trained all his life to defend or the vampires who might just be the death of him.