Lord Of The Vampires Royal House Of Shadows Series, Book 1.

Once upon a time...the Blood Sorcerer vanquished the kingdom of Elden. To save their children, the queen scattered them to safety and the king filled them with vengeance. Only a magical timepiece connects the four royal heirs...and time is running out.... Nicolai the Vampire was renowned for his virility, but in a twist of fate "The Dark Seducer" had become a sex slave in the kingdom of Delfina--stripped of his precious timepiece and his memory...