Codex: Chaos Space Marines (2007), p57 — The Unholy Harbinger

As well as ancient Chapter or Legion warships, Chaos Space Marines make use of space hulks to travel the Warp. Space hulks are massive vessels comprising asteroids, derelicts and other debris that have been smashed together into a single immense structure by the tides of the Warp. Most space hulks drift randomly upon warp eddies, but sometimes Chaos Renegades will activate antiquated engines and employ the power of Chaos Sorcerers to steer a space hulk towards a target.

One of the most infamous space hulks is known by the Inquisition as the Unholy Harbinger. The Unholy Harbinger is used as a mobile base by a large contingent of Chaos Space Marines, at various times including warriors from the Black Legion, Death Guard, Sons of Vengeance, Anointers of Blood and the Pyre. Its first appearance is recorded in a request for aid and advice from the Cloras system - a request that was not met in time, with the Black Templars arriving some four weeks later to find the system in ruins and half of its population taken into slavery.

The Unholy Harbinger was also reportedly sighted in the later stages of the Gothic War, and before the Sacking of Garipedes during the three-centuries-long schism in the Segmentum Solar known as the Tournament of Fear. Most recently, the ill-regarded vessel has been sighted several times near the Cadian Gate, presumably drawn to the sector by the launch of Abaddon's 13th Black Crusade. It was positively identified by Inquisitor Czevak as part of the invading fleet that attacked Belis Corona, and is believed to have also participated in fleet actions around Dentor.