The '''Emperor's Halo''' was an [[asteroid field ]] that was converted into habitable cities by the [[Imperium]]. In 834.[[M37]], the asteroid field was attacked by the ''[[Terminus Est]]'', which fired plague-ridden torpedoes through the cities force domes, which soon spread throughout the Emperor's Halo. Soon afterwards, the Imperial overlords of the cities were driven mad by the rot and death drowning their [[Imperial Citizen|citizens ]] and opened their domes to space.{{Fn|1}}