Due in large part to the emergence of the BookTok community (an online community in which TikTok users share book recommendations and discuss literary topics), the term “romantasy” has gained considerable traction and is now widely used to describe a subgenre that blends the elements of both romance and fantasy, with the romance aspects often dominating the plot. Although the term “romantasy” rose to mainstream popularity in the early 2020s, it was employed in common vernacular as early as 2008, and its tropes and plot patterns can be found in earlier works such as the 2005 debut of Stephanie Meyers’s series Twilight, which features a romance between a human girl and a vampire. Just as the Twilight series engages with elements of fantasy in the construction of the vampiric world and political hierarchy that serve as a backdrop to the protagonists’ romance, St. Clair also employs similar conventions in The King of Battle and Blood, crafting a world in which the Blood King Adrian reigns supreme as the original vampire from which an entire vampiric empire was spawned.

Novels within the romantasy subgenre often prioritize the central romantic relationship over other elements of fantasy world building, and this pattern can also be seen in King of Battle and Blood.