Lilith was one of the oldest vampires and also known as "The Mother" of all vampires.
Lilith came to Sunnydale with her champion, Prince Ada, to attend Dust Waltz, a ceremony to bring back an Old One by the name of Azogg-Mon. In order for her to bring back Azogg-Mon, Prince Ada had to fight Lamia's champion, Cecil. But when Lilith and Prince Ada were out hunting, Buffy Summers killed Prince Ada. Lilith captured Angel so he could replace Prince Ada as her champion, but, after some torture, she didn't find him strong enough to face Cecil. Buffy stepped in as champion so that Angel, Willow Rosenberg, Xander Harris, and Cordelia Chase, who had been captured by Cecil's werewolves, would be set free. Buffy fought Cecil and killed him with a silver dagger. In doing so, she also freed Azogg-Mon. When Azogg-Mon accidentally killed Lamia, Lilith banned him back to the hell he came from.