"Lords of the Underworld" is a popular paranormal romance book series written by Gena Showalter. The series features a group of immortal warriors who are each cursed to house a specific demon within them, resulting in unique powers and challenges. The stories blend elements of fantasy, romance, and adventure, appealing to fans of supernatural fiction. Set in a richly imagined world, the series explores themes of love, redemption, and the struggle between good and evil. Each book focuses on different characters, often intertwining their stories with mythological figures and creatures, such as gods, demons, and mortals.