Killer the Butcher is a merciless leader of the Gaizok race and the primary antagonist of the series. He will use any means necessary to eradicate the human race and often comes up with despicable schemes to do so. He gets enjoyment out of making humans suffer and purposely prolongs their seemingly inevitable demise by attacking the planet little by little instead of using all of his force at once. He is extremely gluttonous and is almost always eating pieces of meat. He is also very self centered and demands constant attention from his subordinates. He becomes angry when his subordinates fail to carry out his orders but doesn't punish them severely or over-react.