The Dusk Raiders were the XIVth Space Marine Legion raised by the Emperor of Mankind on Terra at the dawn of the Great Crusade in the 31st Millennium. After the Emperor discovered the Dusk Raiders' Primarch Mortarion on the poisonous world of Barbarus, and gave him command of the XIVth Legion, Mortarion changed the name of the Legion to the Death Guard after the name of the military force he had raised on his homeworld of Barbarus to overthrow the rule of that Feral World's necromantic warlords.