Underworld is an American action horror film series created by Kevin Grevioux, Len Wiseman, and Danny McBride.

It follows characters who are caught up in a war between vampires and werewolves (called “death-dealers” and “lycans”, respectively, within the films). Most of the films star Kate Beckinsale as Selene.

The first film, Underworld (2003), introduces Selene, an elite vampire-warrior who defies her orders, and Michael Corvin (Scott Speedman), a human who gets caught up in the war. The second film, Underworld: Evolution (2006), follows Selene and Michael as they are hunted by their enemies.

The third film, Underworld: Rise of the Lycans (2009), is the prequel to the series, chronicling the origins of the vampire-lycan war. The fourth film, Underworld: Awakening (2012), is the sequel to Underworld: Evolution. In this film, humans have discovered the existence of vampires and lycans, and are trying to eradicate both species. A fifth film, titled Underworld: Blood Wars (2016), focuses on Selene who tries to stop a new war between vampires and lycans. The series received generally negative reviews from critics, but amassed a strong fan following and grossed a total of $539 million, against a combined budget of $207 million