The Deathwatch are the elite of the elite. Recruited from the ranks of the Adeptus Astartes, humanity's power-armored Space Marines, the Deathwatch embark on the most difficult missions in the name of the Emperor. Genestealer Cults are the advanced infiltration units of the Tyranid Hive. They infiltrate human civilization and interbreed to create monstrous hybrid cultists. Deathwatch: Overkill pits these two forces against each other. The Deathwatch player controls a squad of marines plus one Terminator and one White Scar on a bike. The Genestealer Cult player controls one Patriarch, one Magus and 37 Genestealers ranging from purestrain to fourth generation cultist. Each player uses dice and cards to shoot and force the action.