Vortigaunts are a fictional extra-dimensional species in the Half-Life series of video games by Valve. In Half-Life and its three expansions, Vortigaunts are frequently encountered by the player as hostile non-player characters in Half-Life and later as allies in Half-Life 2. The Vortigaunts are depicted in Half-Life as being an enslaved race in an alternative dimension called Xen, subservient to a large creature called the Nihilanth, which itself is a slave to undisclosed masters. In Half-Life 2, the Vortigaunts have broken free of their slavery following Gordon Freeman's killing of the Nihilanth at the end of Half-Life, and actively assist the player and other humans in resisting the Combine occupation of Earth.
