The Night Prince series is a spin-off from the Night Huntress series by Jeaniene Frost. It focuses on the character of Vlad, a powerful vampire with an intriguing past. The series delves into Vlad's backstory and his romantic relationship with Leila, a woman with psychic abilities. The Night Prince series is filled with suspense, romance, and supernatural elements, making it a captivating read for fans of the Night Huntress series.