Clan Pestilens is the fanatical plague-cult of the Skaven, a brotherhood of diseased monks who worship the Horned Rat through the spreading of pestilence and rot. Their Plague Priests and Plague Monks revel in filth and contagion, their bodies riddled with sores and swellings that would kill any other creature, sustained by fervent devotion and warpstone-tainted corruption.
The clan's history is one of schism and holy war. Having discovered the secrets of disease during a long exile in the jungles of Lustria, Pestilens returned to wage a devastating civil conflict known as the Wars of the Rat against the other clans, a struggle so ruinous it nearly shattered the Under-Empire. Only the intervention of the Horned Rat and the founding of the Council of Thirteen brought an uneasy peace.
In battle, Plague Monks fight in frenzied swarms, wielding rusted, filth-caked blades and hurling censers that belch poisonous clouds. They welcome death as communion with their god, and the plagues they brew have depopulated whole cities of the surface world.