The Damaroth is a Deathwatch Watch Fortress. A vast artificial ring around a glowing moon, it is the centre of Deathwatch operations in the Centaurus Arm of the Ultima Segmentum. The artificial structure wasn't built by human hands, and in fact predates the Imperium. It is one of six such structures found so far, each one converted by the Inquisition of the Ordo Xenos, into a Watch Fortress. No trace of the beings that made them has been found.