Melusine is a creature derived from the classical lamiai figure. Stories claimed she was the daughter of King Elinas and his fairy wife. Angry at her father, she and her sisters turned their magic against their parents, and for her actions, her mother turned her into a serpent from the waist down.
Melusine would remain this way until she found a man who would marry her on the condition that he would never see her on Saturday (when her serpentlike body reappeared).
She found Raymond of Poitoi. When they married, Melusine used her magic to help him rebuild a kingdom.
When they had children, each were deformed. The situation came to a head when one of the children burned an abbey and killed a hundred people. In his anger, Raymond revealed that he knew Melusine’s secret. She reacted by accepting the curse upon her, realizing that she was condemned to fly through the air in pain until the day of judgement.
Until the castle fell, Melusine would appear before the death of each of Raymond’s heirs to voice her lament. She thus became a banshee- the wailing spirit of the House of Lusignan.
After the castle fell to the French crown, people reported Melusine appeared before the death of a French king. She was not a vampire, but did show the direction in which at least one of the older vampires evolved.