Somnara, also known as Deirdre, Osybus, The Gentleman Caller, and many other names, is a succubus that spent many years contained in the amber temple, until her amber containment was broken by soldiers under the command of Strahd Von Zarovitch. Once unleashed, she turned Strahd into the first vampire. Whether before, or from within, her imprisonment, she was able to take on a human guise with which to conspire with Rahadin while Strahd was still a child. While conspiring at this time, she was beheaded by Cherish Heiss, who had appeared from the future using Strahd's journal, enchanted with chronomancy by Baba Lysaga.
According to a Chultan couatl, Somnara and her sister are both born of Morwell. She is said to have a feud with her sister, a river spirit presumed to be Deirdre. This has caused her to dislike the feeling of running water, a trait that she has passed on to all vampires.