The Guardian's Hunger. A dark sacrifice, a parasitic bond, and the monster that demands everything (en Inglés) - P Hartwell

A warrior is sacrificed as a groom to an ancient beast that lives within Shadowveil Hollow to protect his kingdom from a rotting plague. He arrives expecting a violent death but finds a cursed guardian whose physical form is tethered to his own genetic lineage. As they form a forbidden romantic connection, he realizes the creature survives by consuming the sanity and vitality of those it protects. Their growing bond triggers a parasitic hunger that begins to physically transform the warrior and threatens to devour the very citizens he swore to defend.