The Strogg are a hostile cybernetic alien race featured as the main antagonists in the Quake 2 and Quake 4 video games, and recently in Enemy Territory: Quake Wars. The Strogg are cybernetic constructs of unclear origins that reproduce by taking biological components and fusing them with advanced technology in the brutal surgical process of stroggification that enslaves their minds and enhances their bodies for war.
The Strogg's need to harvest biological components for their own augmentation, and the flesh of slain enemies for the creation of stroyent, is their primary
motivation, since it is necessary for their survival. This motivation led the Strogg to Earth, which they promptly invaded, slaughtering millions of humans just to harvest their corpses. This Strogg aggression led to humanity's long war with them that has continued unabated ever since.