A Genestealer Cult is a xenos-worshipping secret society made up of and controlled by Tyranid Genestealers that thrives in the dark corners of the Imperial underworld across the galaxy. Secretive, stealthy, and utterly malignant, Genestealer Cults are the cankers growing unseen in the hidden spaces of Mankind's realm. Some cultists are truly monstrous, skulking along dank tunnels with robes or hessian sacks covering their hybrid xenos anatomies. Others are merely pallid and bald, able to pass for loyal Imperial citizens whilst their wyrm-form tattoos remain hidden. These latter-generation brethren mingle amongst the herd of Mankind like wolves in sheep's clothing, working so hard amongst the crumbling machineries of Human industry that none spare them a second glance -- but under their work fatigues and rough miner's apparel, they all bear the mark of the alien.