The Thri-kreen are about as “native” as anyone can come to Infra. Though not a by-product of Infra, directly, their ancestors millions of years ago sought refuge in the depths of the World and have been here since. They have never gone beyond a tribal type of existence and do not farm. Their nourishment has come from years of inter-tribal warfare and out-right hunting of other species (sentient or not). This leads many of the inhabitants of Infra to believe they are evil and barbaric, but the Thri-kreen simply do not view survival as good or evil or black and white.
The Thri-kreen stand up-right but are much more insect than man and are born in clutches like insects are. These clutch-births result in tribal-familial affiliations and massive population spikes. Most Thri-kreen are malnourished unless they can goad another tribe into open combat, whereupon the victors will feast on the bodies of the fallen or they can find natural cave-dwelling creatures to hunt. They also receive stipends of food from the Human Holds who dole out all of the surface’s food deliveries.
The Thri-kreen have an outlook on life that is considered very alien to the rest of the peoples of Infra and few outsiders in any way understand their existence. Much of the way they look at existence they group into a single concept called the “Cave.” Life in the “Cave” is harsh and dark and savage. Eating a member of your tribe who has recently died is not evil — it is survival. The Cave determines who lives and who dies as much as any one person or tribe does.
The Thri-kreen have always existed on the left-over scraps of the Drow and Exiles, however in recent years there have been whispers of rising Warlords from the most far-flung tribes who have begun to unite and absorb smaller tribal bodies under their banner. They are calling for a sovereign Thri-kreen home that is not just the scrap left-overs the Exiles and Drows don’t want. As it stands, the Thri-kreen live in The Hive, a honeycombed network of tunnels and caves that are a mix-match of artificially excavated nests and naturally formed fumaroles and air pockets.