Billy Lane was a vampire hunter. Learning self-defense to cope with homophobic bullying in high school, Billy eventually used those skills to protect his home town from the newly-emerging "zompires". Unlike most vampire hunters, Billy was directly inspired by Slayers and self-identified as such, despite having no supernatural powers. He later moved to San Francisco, where he befriended and worked alongside Buffy Summers.
- "When you find the family you're supposed to have, you know because they know when not to say anything."
- ―Billy referring to his grandmother, Sky.[src]
Billy Lane grew up in the Californian town of Santa Rosita. As a teenager, he came out as homosexual; his parents subsequently kicked him out of his home and he went to live with his grandmother, Sky, instead. His best friend at school was a girl named Katie and he developed a crush on a popular student who he and Katie privately referred to as "Cute Devon".
Despite the support of Sky and Katie, Billy also suffered frequent bullying from cruel high school students Post and Garron, who mocked him for his sexuality and his parent's rejection of him. Sky suggested home schooling, an option which Billy refused, believing he could handle the situation; instead, he started teaching himself to fight back, something his pacifist grandmother disapproved of. When Devon discovered Billy training in the school gym one morning, the boys started talking for the first time.
- "What's the right way to fight back?"
- ―Billy Lane[src]
One night, while walking home from school, Billy was again confronted by Garron. As Billy prepared to fight back for the first time, Garron was murdered from behind by Post, who had been turned into a "zompire". He was quickly pulled to safety by Devon, who explained that vampires had become more feral in the wake of the end of magic. Devon also revealed his knowledge of Slayer mythology and, having witnessed Billy's self-defense training, suggested that Billy begin training as a pseudo-Slayer. Billy was initally sceptical of his own ability, but when Post managed to break into his room and attack them again, he successfully slayed his first vampire and saved Devon's life.
- "So you're willing to try? I'll be the Watcher and you'll be the Slayer and we'll be magnificant together?"
Billy began training regularly under the guidance of Devon, who took on the unofficial role of Watcher to Billy's Slayer. As the boys spent more time together, Katie began to realize that Devon was attracted to Billy, although Billy himself remained oblivious to this fact. As the true scale of the zompire threat became apparent, Devon began to have second thoughts about letting Billy put himself in such danger. However, when the local library where Sky volunteered was attacked by a pack of zompires, Billy defied Devon to go and rescue his grandmother. Not wanting Billy to go alone, Devon followed and finally admitted his feelings for him. The boys reconciled and worked together to fend off the zompires and save the civilians, including Sky; in the aftermath, Billy and Devon became an official couple.
- "The best way to fight back is to remember you are not fighting alone. Even when it seems you are."
- ―Buffy welcomes Billy to the Scoobies[src]
Some time later, Billy travelled to San Francisco and tracked down Buffy Summers, the former leader of the Slayer Organization. Joining the Scooby Gang, Buffy's supernatural-fighting team, Billy gained the opportunity to patrol and train with a real, experienced Slayer. Sky permitted her grandson to live with Buffy on the condition that he Skype her after every patrol, and he maintained a long-distance relationship with Devon. Working with Buffy, Billy also assisted the SFPD's newly-established Vampire Task Force, run by former homicide detective Robert Dowling.