Koros is tidally locked with Yridia II, the same side always facing the planet. Without an insulative atmosphere, the dark side is much colder than the starlit side. Formerly the home of House Cestus, this moon became abandoned after an outbreak of undead. While some facilities underground remain, most of the surface installation was destroyed in the orbital bombardment when the complex was closed.
Contrary to rumors, the undead infestation upon the moon of Koros is not Draugr, but actually Aptrgangr. Only a few Draugr exist upon the moon.