The Osk are quadrupedal, six-limbed beings whom humanity has had several encounters with, few of them peaceful, as the Expansion pushes into their territory. Their homeworld, Oskaran, orbits a white dwarf star which in turn orbits a red giant, forming a binary system.
The extreme weather changes and solar radiation of their home environment induced many evolutionary adaptations in the Osk. These include their dark-pigmented skin, crepuscular activity cycle (that is, they are most active during the cooler periods of dawn and dusk), and their tendency to live mostly in underground warrens.
Although they appear somewhat reptilian, the Osk are actually monotremes (egg-laying mammals). Their lithe, flexible bodies can adopt either a centauroid or fully horizontal configuration. This characteristic has led some humans to use the pejorative term “snake” to refer to the Osk, despite the lack of resemblance.