The Traitor Legions are the most powerful component of the Forces of Chaos. The flesh and Power Armour of these Chaos Space Marines warped and twisted into new, darker and inhuman forms under the influence of the Chaos energies they were exposed to, as well as their shapes, which morphed to embody the corrupted Astartes' new allegiance. Following their defeat during the final epic battle, known as the Battle of Terra, the Emperor pronounced judgement upon the Traitor Legions. They were declared Excommunicate Traitoris.