Hester is the main antagonist of the first volume of the Buffy The High School Years graphic novels, Freaks and Geeks.
Not much is known about who she was as a human but from most of the dialogue, she and her friend were turned fairly recently with the story implying she likely sired them not long after she was turned. She and her friends having holed up in a cemetary where they mostly play board and video games at night when not hunting.
One night her friends and she tried to get into a club exclusive for vampires but were denied entry for their lowly status. Demanding to be let in she asked if there was anyway the bouncers would do so with one of them offhandedly suggesting to kill the slayer of a joke (largely out of annoyance for her attitude and hoping Hester and her friends would get staked). She took it to heart and convinced her friends to join her. They happened upon Buffy while she was hunting and attacked her, managing to catch her off guard and knock her down and escape. Embolden by this, they resolved to finish the job with Hester revealing she got a spell book offline to help them.
In the final confrontation with Buffy, Hester had her friends surround her and enacted a spell to summon a demon. However she didn't tell her friends that they were to be used as sacrifices in order to do so, much to Buffy's disgust that she callously made them pawns just to boost her own status. Hester cited them as "losers" and tried to command the demon to attack Buffy. However the demon revealed that Hester didn't read the spell entirely as she needed four sacrifices to control it, having only give up three and chastised her for using magic she wasn't familiar with before crushing her. Leaving Buffy to kill the demon.