Since I'm not sure of any specific 'apache caress' romance novels, in general, romance novels often have strong emotional connections between characters. They typically involve a central love story, with elements like attraction, conflict, and resolution in the relationship.
I'm not sure specifically which 'apache caress' romance novels are out there. You could try searching in large online bookstores like Amazon. They usually have a wide variety of romance novels and might have ones related to this if it's a known sub - genre or series name.
The Hunter x Hunter manga is unfortunately not complete. The author has faced various issues that have led to intermittent breaks and an unresolved storyline.