A Slayer in the television series Buffy the Vampire Slayer and Angel (both created by Joss Whedon), is a young woman bestowed by fate with supernatural powers and abilities that originate from the heart, soul, and spirit of a pure-demon.

The opening narration in the Buffy series states "In every generation there is a chosen one. She alone will stand against the vampires, the demons, and the forces of darkness. She is the Slayer."

While they are commonly referred to as "Vampire Slayers" within the series, even by Watchers and vampires themselves, The Slayer operates as a defender of humanity against all supernatural threats.

The reputation of the Slayer is well-known and revered even throughout other dimensions. The notion of the Slayer has been compared to the equivalent of a Demonic "Boogey-Man", incredibly feared and considered by most to be essentially unconquerable.

Rhonda Wilcox explains that the First Slayer was violated by the Shadow Men. She contrasts this with Buffy's offer of choice to the potentials. Wilcox notes that despite the message of sharing power around the world, not all women are made slayers. She then equates being a slayer with being a leader. Patricia Pender discusses the potentials and sharing of power as well, noting the cultural aspects and providing critique of the cultural portrayals.

Pender also analyzes the reception of Buffy as the slayer in early criticism of the show: "the Slayer is celebrated at the expense of the girl, and the composite character is found inexplicably wanting," going on to explain this is a flaw in analysis of the character. Pender goes on to discuss the "struggle to balance the demands of her supernatural duties as the Slayer and her desire to live what she sees as a normal teenage life. As several critics have pointed out, this struggle literalises the challenges many, if not all, adolescents experience when negotiating their entry into the adult world".

Cynthia Fuchs similarly says Buffy's character brought an understanding of teenage life, but that her "'secret identity' as the slayer exacerbates such ordeals and dreams. She explains further, when analyzing a sequence with the First Slayer, "Buffy's perpetual sense of displacement, her sense that she belongs to another "race", apart from her world (which is populated by humans, demons, and vampires, communities into which she never quite fits), is made concrete for her in the First Slayer.

"In every generation there is a Chosen One. She alone will stand against the vampires, the demons, and the forces of darkness. She is the Slayer."