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 remained, most of the surface installation was destroyed in the orbital bombardment when the complex was closed. The moon was re-opened as a Tarentum stronghold when the old Cestus Complex was destroyed, and House Cestus was re-opened, with the wreckage of the VSD Corsair becoming the House's new headquarters and stronghold. However, following the closure of House Cestus, the Cestus Complex became simply The Corsair Facility for use by Tarentum's military. Now, Koros serves as home to it and the Yridian Military Academy at Corsair Facility.