Realm of Chaos: The Lost and the Damned (1990), p77 — Cosmic Monoliths

The Warhammer World is bound by storms of magic so that it remains isolated from the other worlds of the human galaxy. Elsewhere, the forces of the Imperium tenaciously fight the influences of Chaos, so that the open aggression of Chaos Champions and their forces is restricted to zones not controlled by the Imperium. On worlds where Champions of Chaos attain daemonhood or death there are monoliths to their memory just as on the Warhammer World. Cosmis monoliths are tablets, flat stones, or death caskets that float through space itself. They can celebrate a Champion whose mortal life ended while battling an engagement between space fleets. Often they orbit a world, transmitting their inscriptions to passing craft or projecting their image directly into spaceships.