Isn't a romance/horror hybrid a Gothic?
Often, yes, but Other Kingdoms
doesn't really fit that template. The protagonist and POV character is a wounded WW I vet, not an ingenue, and the plot doesn't play out like a traditional Gothic.
It's more of a twisted love triangle between a soldier, a witch, and a sexy fairy princess.
(That being said, I did ask Richard to delete one scene which I thought was too horrific for this particular book. It was indeed at odds with the overall tone of the story.)