An alien species native to a system deep within gusano space, the kopfzwei (Kopfzwei caridea xenos) are a sapient deep-sea species resembling a cross between Terran shrimp and clams in body structure. A medieval society when first encountered by the gusano, they have become slaves and servants for many gusano masters. They are a rarity in human society and only the most affluent can own a kopfzwei slave.
The kopfzwei are native to BR-55-VII, a world only visited three times by humans. It is a cold world that, were it covered in water, be coated in ice. But unlike most worlds with large liquid bodies on them, the world of BR-55-VII has oceans of liquid hydrogen fluoride. Hydrogen fluoride is the primary solvent of all life on the world and most organic compounds are derived from paraffins. Because fluorine is cosmically rare, kopfzwei in gusano and human communities are expensive to maintain. The gusano have developed suits for the kopfzwei to be immersed in chilled hydrogen fluoride. Water is deadly to all life on BR-55-VII, as it turns HF into hydrofluoric acid; a common way to execute kopfzwei is to immerse them in or inject them with water. Because of the complex biological requirements of the kopfzwei, they are never used in combat.
Kopfzwei are, as their name states, double-headed creatures. One head is linked to the digestive tract while the other is a manipulation tool, the only one the kopfzwei anatomy possesses. Both heads have eyes. The kopfzwei have twelve legs and two non-manipulator claws. They carry a large shell on their backs, containing most of their internal organs including the brain, which they can retreat into when there is danger. This shell is normally amputated when kopfzwei are given suits for operation in alien environments; the suits are grafted onto them and they can never leave. The kopfzwei are hermaphroditic and impregnate one another during reproduction; traditional kopfzwei families in the northern areas of BR-55-VII are one parent one child, while a two parent, two child system is common in the southern areas. Several devastating wars have been fought over this difference. Kopfzwei lay miniature shells which grow into the sediment; kopfzwei are sessile lifeforms in their youth, which can be attacked by predators, including mature kopfzwei. This cannibalism was ended by most civilized kopfzwei communities, as they wished to have as many young as possible for their wars. As a kopfzwei shell matures, it becomes mobile.
In the distant past, kopfzwei were nomadic and moved in great herds, but with the advent of agriculture became sedentary. Prior to discovery, kopfzwei society revolved around geothermal vents. These vents provided warmth for gestating young and bacteria-like life to feed sessile agricultural life and livestock. More recently these vents were a source of heat for cerallurgy (the manipulation of paraffin-based waxes taken from the corpses of native lifeforms). Geothermal vents were more important to the kopfzwei as oil fields were to pre-Collapse humanity; the resulting kopfzwei cultures are extremely territorial, even more than humans. Large stone and wax walls were built to defend vent areas, resembling the castles of old but much grander in scale. These castles also served as homes for families and protected the vents, nurseries and farms within. Kopfzwei wars largely focused on tearing down enemy walls and defending friendly ones. The kopfzwei domesticated large, lobster-like creatures dubbed the hummerartige by the Coalition scientists that first saw them. Hummerartige are closely related to kopfzwei, a relationship similar to that between gorillas and humans, but preyed on the kopfzwei for most of their prehistory. They were eventually domesticated and bred when the kopfzwei took hummerartige eggs and drove wild hummerartige to extinction. Hummerartige are semi-sapient and are used as draft animals and cavalry.
The gusano encountered the kopfzwei in the 2500s, according to the projections made by most human xenobiologists. Few documents about first contact are in human hands, but what is known is that first contact was extremely violent and saw the use of weapons of mass destruction. The kopfzwei “kingdoms” quickly surrendered to the gusano. The survivors were used as slaves in the slaveholding gusano cultures and sometimes used as sacrifices. They allowed the kopfzwei to settle the MP-044 system, which had a world similar to their home. Humanity first encountered the kopfzwei when a gusano ship full of them was captured by Coalition forces during the Endless War. The Coalition soldiers first believed that the kopfzwei were a related to the gusano, either as subspecies or through mutation or genetic engineering. It was only after greater analysis that the Coalition realized they were dealing with another alien species. Their origin was unknown until a Technocracy battlegroup encountered BR-55-VII. Before being forced to retreat by gusano forces, the battlegroup left with tens of thousands of mature kopfzwei and several hundred eggs. The Technocracies visited the world a second time and a slaver fleet assaulted the world shortly afterward.