Genestealers (Corporaptor Hominii) are a fictional alien species in the Warhammer 40,000 universe, and the opponents of the marines in the Space Hulk board game. In more recent versions of that universe, Genestealers are a biological subgroup of the Tyranids, a nomadic alien race comprising many genetically engineered forms.
In 4th Edition of the wargame, there are two subgroups of the Genestealers: the Broodlord and the Genestealer. In the 2nd Edition of the game, there are five subgroups, representing the Genestealer Cult variant army: Genestealer Patriarchs, Genestealer Magus, Genestealers, Genestealer Hybrids, and Brood Brothers. For information concerning biomorphs and other mutable genetic characters of the Genestealers in the game, see Tyranid Genetics (Warhammer 40,000).