High Quality Content by WIKIPEDIA articles! The Combine, also referred to as the Universal Union, is a multidimensional empire, which serves as the primary antagonistic force in the Half-Life video game series, developed by Valve Corporation. The Combine consist of alien, synthetic, and human elements and dominate Earth. They are regularly encountered throughout Half-Life 2 and its episodic expansions as hostile non-player characters as the player progresses through the games in an effort to overthrow the Combine occupation of Earth.