|War World, Mining World, Ice World
Muz is an Imperial Mining Ice World, that contains an airless but toxic atmosphere. Its population lives aboard Deep-miners, which are large roaming mining vehicles that drill promethium from beneath Muz's surface.
Sometime after the Great Rift's creation, the world suffered a rebellion that led the Dark Angels Chapter to arrive and begin restoring order. They soon discovered though, that Muz's population had been infected by Genestealers, which were responsible for the rebellion.