The Slayer of Slayers was a Slayer who originally took over a large portion of his native galaxy by winning over both members of his own species and large numbers of Orks and uniting them in a so-called Slayer-Ork Horde. The Slayer of Slayers, after conquering a large portion of the native galaxy of Orks and Slayers, tried to look for extragalactic territory to conquer. He directed Horde forces to invade the Milky Way Galaxy, but the Milky Way Imperium, the starship fleet of the Spacing Guild, and Sardaukar military elements repelled the Ork and Slayer forces.