From publisher blurb: Some worlds in the interstellar government are what humans consider overcrowded; in many cases, this is the result of a small world with an overwhelming immigrant population that relocates to it for whatever reason. But sometimes, the native sapients have a birthrate that is so out of control that the local biome can barely cope without extraordinary biological measures. One such planet was discovered early in the interstellar government’s history, but initial contact wasn’t peaceful. In fact, the first survey crews arrived as the entire planet was undergoing what could only be described as a brutal, cannibalistic war as the inhabitants — a sapient arthropodal species — fell upon one another with abandon. Only after a year did the violence die down enough to allow the interstellar Scouts the chance to contact the natives…who welcomed the strangers warmly. Over time, the Scouts learned that the natives, called Xxn (the closest that human vocal structures can approximate the sound) are a xenophilic people whose population and breeding pressures periodically drive them to kill one another as a biological imperative to control their population. Lifeform Reading: Xxn is for 2D6 science fiction games such as Cepheus Engine and The Original Science Fiction Roleplaying Game (OSFRPG), although it’s usable with other systems with a little work.