The (More Than) Complete Cast of CVRPG
Heroes, Villains, Low-lives, and Agents of Leisure
Born in the 17th century to the noble (if largely ignored branch of) the Bartley line, Elizabeth was an odd girl even from a young age. Odd may not be the right term. Cold-blooded. Rather murdery. Evil. Even as a child she loved to kill, to torture and maim all those "lesser" than her (which, as she was a noble was pretty much everyone). She started evil, and by the time she grew up she was straight up a serial killer.
But murder wasn't enough -- Elizabeth quickly became obsessed with the dark arts, with learning all she could about the blood she spilled and the deaths she caused. She son learned about the vampires, about how blood was a lifeforce to them that kept them eternally young and eternally powerful. Elizabeth knew she wanted to become a vampire.
Still, it wasn't as though vampires were beating down her door to embrace her, so she had to find her own way into vampirism. She managed it by killing many, many young girls. She's kill them, drain them of blood (into a tub, naturally), the bathe in the blood, coating her skin and stealing the youth from the lifeforce in the blood. In effect she became a vampire without ever drinking a drop.
Of course, killing young girls will eventually get you noticed, especially if you do it enough (...not that we're speaking from experience, honest). Eventually the king sent his men to arrest Bartley. They bricked her up in a tower, leaving her there to die. And she would have, too, if not for the intervention (finally) of a vampire.
When Elizabeth says she's the niece of Dracula, is an affectation (much like how Dracula calls Darkmoon his "son") -- Dracula embraced Elizabeth after having heard so many stories of all her killings. With her newfound vampiric powers, Elizabeth was able to escape her tower. She went with Dracula to serve as one of his lieutenants, and she swore that she would do everntyhing she could to assist her "uncle" with anything he needed.
Thus, when Dracula died, Elizabeth was there to perform the Black Mass Ritual and bring him back. She even aided her uncle by building (or taking over) several fortresses, leaving multiple locations that heroes had to fight through before they could eventually get to Dracula.
Naturally, he still lost because Dracula always loses. But Elizabeth did her best, and that's all a proud uncle can expect from his niece.