- ""It matters not how I kill you mortals, as long as you die screaming. We will rip and tear, until all that remains of your meager existence is your blood staining our armour.""
- —Unidentified commander of the Gerasene Host assault on Theta-9
The Gerasene Host, were a little-known Blackshield warband that appeared during the middle years of the Horus Heresy in the 31st Millennium. The Host appeared to be the result of rapid, unsanctioned gene-seed hybridisation processes first encountered in the middle period of the Heresy. The source of the Host's gene-seed is unknown and the warriors themselves appeared unaware of their true lineage. Some Imperial strategio-savants have posited that the Host were created as a living terror weapon, wrought by an unknown hand and released into the galaxy to sow death and destruction in the ultimate furtherance of the Traitors' cause.
There is little information in regards to the origins of this mysterious Blackshield group, other than some of the actions they took part in, during the middle years of the galaxy-wide conflict known as the Horus Heresy. The Gerasene Host are known to have taken part in the infamous Treab's World campaign, a conflict that burned for four long years and which ultimately drew in and defeated a large contingent of the Salamanders Legion. While the Host operated independently, its strategies were in retrospect clearly co-aligned with those of the Death Guard and Emperor's Children forces also deployed to Treab's World.
It was often theorized that the Host were created as a living terror weapon, created by parties unknown to bring as much death and ruination upon those still loyal to the cause of the Emperor in order to further the aims of the Traitor Legions. This was in accordance with the idea that they were the result of unsanctioned gene-seed experimentation in the midst of the Horus Heresy in an effort to increase the strength of Horus' traitors.
In general, most Blackshield forces deployed only those ground units that could be rapidly set down onto a planet's surface from orbit, limiting ground vehicles to Rhino and Land Raider variants that could be carried by a Thunderhawk Transporter or within the hold of a Sokar pattern Stormbird. Nevertheless, there were several known exceptions and not every Blackshield force operated in this manner; the group known as the Gerasene Host, for example, deployed without warning into the northern sulphur deserts of Treab's World and fought for many months before departing just as suddenly using craft they are thought to have secreted in hidden caverns near the planet's northern pole.
Most of these warriors wore production Mark V pattern Legiones Astartes power armour, their source unknown. Having never borne the heraldry of any Legion, beneath the accrued weathering of a long campaign, their battle-plate displayed the bare metallic grey of unadorned ceramite.
The markings they bore were typical of the Host, each bearer applied what appeared to be arcane and idiosyncratic glyphs of unknown provenance. The "L" sigil on the right shoulder pauldron was worn by most warriors of the Host, its significance unclear to Imperial savants.
- The Horus Heresy - Book Six: Retribution by Alan Bligh, 94, 223