The formal definition of the Cossipae can be traced to a conference from 52991 lky which led to the founding of the Cassiopeia Treaty Organization. This began as a mutual defence pact between the Hatelese Republic (forerunner of the modern Hatelese Commonwealth), the Kafin High Court, and the Sin-koi to protect colonies on the border of territory claimed by the Kolidian Empire. The Lyrisclensiae agreed to join the CTO with observer status, although this ended some centuries later as part of the settlement of the Hatelese Autonomy Dispute. Over time, the CTO welcomed more new members, including the Ritzang (after the collapse of the Kolidian state), Xhomitz, and Twôlish, none of which had organized governments. Today only about two thirds of all species classified as Cossipian actually have some representation within the CTO, but the designation persists as a catch-all category for post-human species, especially the emancipated.
The Sin-koi are natively subterranean. They are often stereotyped as ill-tempered, but it would be better to say they are habitually laconic and do not expend much energy on politeness; indeed, they get along well with the notoriously blunt Lyrisclensiae. The Sin-koi are predominantly male (2:1), and present a higher-than-average adaptation rate. Physically the Sin-koi manifest various atavisms. Hunched figures, hand-like feet, and peculiar ichthyose skin believed to be an adaptation for life in a subterranean environment where uranium and other radioactive ores create hazards. The Sin-koi are also heavily melanistic, and some may even present black sclerae.
The Sin-koi were separated from the main human lineage some three hundred thousand years ago, long before the founding of the Trestunarion by the Lyrisclensiae. It is generally believed that this was a matter of enslavement, but it may just as well have been a result of being stranded on a world in the vicinity of a binary star undergoing a nova, which would have driven them underground, subjected them to intense bombardments of radiation, and destroyed any means of transit they previously had. Records showing that the Sin-koi have since been enslaved on several occasions reinforce the idea that the myth of their initial isolation was simply cobbled together from later incidents of capture.
The Sin-koi generally eschew conventional forms of art in favour of the abstract study of set theory and organizational structure. This has resulted in some profoundly bewildering building layouts, and makes them excellent at optimizing complex programs and machines, but further distances them from the other cultures.
The Sin-koi believe that the darkness is the same as sleep, and that the shadows cast by light are the essence of life. Albino, large-eyed cave dwellers, they must wear heavy sunglasses to cope with direct sunlight or risk being overwhelmed like a deer in headlights. Light is central in their mythologies; they are accustomed to very dim bioluminescence, and brightly glowing artefacts are often the subjects of legends. They believe in a phenomenon best translated as "inner light," which is the literal ability of the very wise to discover truth by emitting luminance both physically and mentally. This passion for dualism is the driving force behind their fascination with mathematics and geometry, as adjacent universals (existing in some unknowable cosmic medium) are the most likely to be exposed by inner light. Illogical jumps in creativity are explained this way.
Hallucinogens are important to them. Such drugs unlock much. They have a natural attraction to haspina and envy the Lyrisclensiae. This has led to a pilgrimage of sorts to Thet. They are generally solitary creatures, long-lived, but usually developing all their knowledge from scratch with little teaching. Some of the wisest know no language, instead using fantastically elaborate, ever-growing carvings as mnemonic devices, where patterns and shapes of unique design, known only to their creator, correspond to abstract ideas.
Homo sapiens kafiae
The Kafin are also short, like the Sin-koi, but instead present much more slender figures. They have pale, almost white skin, ropey tails, and non-functional eyes, for which they compensate with excellent hearing and an extremely powerful sense of smell, which together have been likened to short-range telepathy. The Kafin are slightly more likely to be female (55%) than male (40%), although a small fraction (the remaining 5%) are born with ambiguous anatomy and are treated as a third gender.
It is known with certainty that the Kafin were isolated from the Telai through enslavement around 33000 LKY, some hundred thousand years ago. Their masters used them as pilots, and deliberately engineered blindness as a way of making them dependent on specialised equipment that restored the sense of sight as desired. Eventually, however, the other senses of the Kafin evolved to such a resolution that escape and subsequent survival were practical. On Thet, most either use similar hardware to restore their sight, or have had surgery.
Culturally, the Kafin are very much like the Telai, although they are wary of anything resembling a chain of command. Their ships are hence generally run by sortition or consensus.
The Hatel are unique in that they do not descend from the Telai directly, but from the early Lyrisclensiae, before that species eliminated males from their population, about 170000 years ago. They are the largest organized human species, numbering trillions across their millions of star systems and vast colony ships, and are generally regarded as second only to the Lyrisclensiae in terms of technological development, although there are certainly more advanced non-human species. Their nation-state, the Hatelese Commonwealth, commands immense resources, and often serves the role of peace-keeper in disputes involving one or more human factions.
However, being so close to a post-scarcity civilisation, they are incredibly susceptible to vice; a huge portion of their industrial capacity is devoted to entertainment of various sorts. At times this has interfered with the effectiveness of their military, which was historically regarded a system of brilliant artificial intellect seriously compromised by the fallibility of human beings. More recently, especially since the Hatelese Autonomy Dispute, in which formal oversight by the Lyrisclensiae was abolished after millennia of parental interference, the military has shown itself to be respectably disciplined and, at times, even intimidatingly fascist (which is quite laudable for a culture often regarded as being dangerously close to anarchy.)
Most Hatel exhibit greenish-brown skin, although their spectrum runs from the cerulean of the Ritzang to the greys of the Sin-koi. They do not have a distinctive average build, but share the unusual average height of the Lyrisclensiae, and are very manually dexterous. Most have noticeably pointed ears. As they have the technology to reshape their bodies to some extent at will, gender and sex balance is hard to assess; even one individual may vary over time, and cultural trends come and go. Birth rates are typically very close to the ancestral human biological norm of 1:1.
Histories of sexual slavery are not uncommon amongst the Cossipai. On Thet, the most prominent example of this are the Ritzang, who were subjects of the Kolidian Empire, a secluded, remote culture that was mostly known for its tendency to subsume stranded outsiders. Those who escaped servitude often ended up in indentured servitude of one form or another, or even slavery, unable to repay the high expense of the long trek from Kolidian space.
The Ritzang were largely remade in Kolidians' image, although retained the essential bipedal form of other humans. They were given blue-green skin with an unusual pattern of scales, reptilian eyes, and small nubs of bone that jutted from their elbows, knees, and shoulders, along with a ridged tail of similar genetic makeup to that of the Kafin. Standing next to a Kolidian, one might assume the two species were related, but this is merely mimicry.
Most Ritzang are female. The Ritzang are one of the few races with an abundance of true hermaphroditism, giving them a 55% female, 25% hermaphrodite, and 20% male mixture.
The Ritzang are frequently viewed with suspicion by other humans because of infamous incidents where one of their people resorted to exceptional means to escape slavery. The majority are solitary, and used to being unable to trust others, hence (rather like the Xhomitz) they do not often contest this reputation, as they feel it is better to keep others at a distance.
On Thet, the Ritzang have struggled to overcome their past, and started to form proper communities again. By the time of the Iron dynasty many were skilled musicians and bards, and the Lilitai occasionally collaborate in artistic endeavours with them.
Unlike most Cossipai, the Xhomitz have never been enslaved on a massive scale by another species. They are survivors, used to poverty and hardship aboard the many merchantile space stations and multi-species colonies of the universe; to them, Thet is just another neighbourhood. Possessing very dark grey skin, they are often slender but generally tall. The majority (70%) are male. They have gradually evolved low-light vision in the infrared range, though at the cost of pervasive red-green colour-blindness in the visible spectrum, and with a vitamin-rich diet can achieve performance superior to the Sin-koi.
The Xhomitz split from the Telai by choice some hundred thousand years ago in pursuit of personal wealth. While more than a few succeeded in building up financial empires, most of their descendants have struggled with money and survive on the fringes of society. Occasionally some will integrate with a Telaian or Kafin crew.
The Twôlish are very unique amongst the Cossipai; for a long time it was debated as to whether or not they were even human. They stand about three feet tall on average, have next to no muscle, and display a bone structure and skin texture very unlike other kinds. They reproduce exceptionally quickly, swear obedience to an impenetrably complex religion full of numerous ever-shifting rules, and have no record of their own history. From birth they are dependant on a powerful stimulant that they call Wôʔ, which appears to be responsible for much of their physiology and culture.
This would be all well and good to other cultures if they were not so terribly fond of dismantling and reassembling machines of all sorts, often with questionable utility. The Lyrisclensiae and Hatel both consider the Twôlish a pestilence, although from time to time they invent something brilliant, thus earning them amnesty for most of their eccentricities.
Regarding the Lilitai and Lyrisclensiae
Because of their cultural isolation and proud history, the Lilitai never integrated with the Cossipians, although, aside from CTO membership, they meet all of the technical criteria to be classified as such. It is generally considered a slur of ignorance to both groups to refer to a Lilitu as a Cossipa, although the line is less clear for the Slokdtabasa of Wemno, who were re-enslaved after the death of the Ksreskézai.
The Lyrisclensiae, on the other hand, are not considered Cossipae even as a technicality, as they chose to isolate themselves deliberately from the Telaian lineage while remaining in full contact with the parent species. On many worlds of mixed human settlement, there is tension between Cossipian groups and the Lyrisclensiae, a state of affairs that likely originates to the Hatelese Autonomy Dispute.