There was also an "Elizabeth" in the book series, "Covenant With the Vampire" that also had an Elizabeth.
This Elizabeth was based on a real person who lived hundred of years ago. She was wealthy and born to the noble class. She was famous for kidnapping young girls and bathing in their blood.
The Elizabeth in "Covenant With the Vampire" was also a vampire. But she was of a different kind. Elizabeth could go out into the daylight. She was a bit of a masochist and loved to torture young women and bath in their blood.
Elizabeth and Vlad pretended to be friends in front of one another. However, they were actually enemies and constantly tried to overthrow the other.