Volume 1: Hyperborea Prime
Hyperborea Prime, a Frontier World situated in the Hyperborea System of the Outer Reaches Sector, Segmentum Obscura. It's climate is one always on the brink of near total freezing, but a temperate belt in between the southern and northern hemispheres exists which experience an average day temperature of 20°C, but drops below -40°C at night, making night lethal to most life. This cold drop -- Known as the 'Feral Winter' to the natives, and 'Frostfall' to the settlers -- Is responsible for a lot of the strife on this planet, and makes it impossible for the ill-suited to survive long.
The temperate zone is a stark contrast to much of the planet which is primarily formed of arctic oceans and desolate frozen wastelands. The Temperate Zone on the other-hand is a warm belt composed of rolling hilly planes, volcanic lakes, and dense fir and pine forests. The forests and volcanic lakes is where much of the planet's life dwells, including rich and varied game which the planet's Native and Settler population sustains itself. The weather of the temperate belt can vary greatly, from light downpours to relentless torrential rainstorms, to even freak ice blizzards which can flay flesh from bone. Machinery seldom lasts long on the planet, even the vehicles of the Astra Militarum fall victim to any number of issues, forcing those that have tried to tame the hostile world to adopt practical ways of getting around -- Including horses.
The Hyperborea System is composed of Hyperborea Prime and it's meteorite-formed moon Hyperborea Minor, Hyperborea Secundus a low atmosphere barren world, Hyperborea Tertiary a small desolate planet close to the sun, and the heavily volcanic exo-planet Ionia which was for a time host to a vibrant Feudal Society, before the planet was rendered barren and desolate by volcanic activity. Hyperborea Minor has undergone an indefinite quarantine to contain a virulent blight, rendering much of Hyperborea Prime's PDF stranded in the planet's sprawling military complexes. The Voidstation 'Maelstrum Indomine XVII' which hangs in Ionia's orbit is where the system is governed from.