The War Hounds were the XIIth Space Marine Legion raised by the Emperor of Mankind on Terra at the dawn of the Great Crusade in the late 30th Millennium. After the Emperor discovered the Legion's Primarch Angron on an unnamed world, and gave him command of the War Hounds, Angron changed the name of the Legion to the World Eaters, in honour of the gladiator force he had led in rebellion on his homeworld whose warriors came to be known as the "Eaters of Cities" for their wrath and violence. Angron expected that his Legion would become the "Eaters of Worlds".