Big Bad

A Big Bad is a term applied (mostly by fans and the show's creators, but also spoken in the Buffyverse) to describe major villains on Buffy the Vampire Slayer. Specifically, it is usually accepted to refer to the single villain that, in each season of Buffy, is the dominant and final one.

The Big Bad is typically not only dangerous (all of the Big Bads threaten some version of apocalypse) but also helps articulate the major themes of the season. Some of the Big Bads are built up and present from the season's beginning (or earlier) - i.e., The Master - and others are sprung as a surprise near the end of the season - i.e., Angelus.

Little Bad/Big Bad
For some of the show, the seasons followed a pattern known as the Little Bad/Big Bad. Through this pattern were the surprise Big Bads introduced. The pattern goes like this: near the beginning of the season, a villain is introduced who appears to be a Big Bad and absorbs much of the heroes' attention in similar fashion to a Big Bad. Then, all of a sudden, midseason this Little Bad is rid of (typically killed) and replaced by the Big Bad.

This pattern in action: Season 2: Spike->Angelus Season 3: Mr. Trick->Faith/The Mayor Season 4: The Initiative/Maggie Walsh->Adam Season 6: Nerd Trio/Warren Mears->Dark Willow

As can be seen, this pattern is rarely perfect, and the specific instances are often disputed. Unlike the other Little Bads, Spike does not die (although it is well known Joss Whedon intended the character to be offed, until James Marsters' portrayal convinced the show's creators to keep him around); the Mayor's presence is well known before Mr. Trick is killed; and Warren dies much later in the season then the other Big Bads.

Nevertheless, creative arguments can be made for different interpretations of the Little Bad/Big Bad pattern. For example, Faith may be interpreted as the true replacement for Mr. Trick in Season 3. Those wishing to conform Season 5 to the pattern might argue Dawn's uncertain identity was the Little Bad for the season, or Joyce's illness.

List of Big Bads
List of the seasonal Big Bads