The Deathwatch Space Marines serve the Ordo Xenos of the Imperial Inquisition as its Chamber Militant, the warriors of last resort when the Inquisition needs access to firepower greater than the Astra Militarum or a team of its own Acolytes or even Throne Agents can provide.
Across the galaxy there are innumerable hostile alien civilisations that threaten Mankind, from the green-skinned Orks, to the monstrous Tyranids, sadistic Drukhari, spectral C’tan, and undying Necrons. It is the sacred task of the Deathwatch to stand sentry against all of these terrible xenos races. They are ready to act when such ancient evils rise to threaten Mankind once more. The Space Marines of the Deathwatch form the first, and often only, line of defence against these inhuman horrors.
Unlike other Space Marines, the ones serving in the Deathwatch are not truly a separate Chapter of the Adeptus Astartes; rather, they are a collection of Veteran Space Marines drawn from all of the different extant Chapters who serve together in the Inquisition’s service for a discrete period of time.
Watch Fortress Hellsong
The Deathwatch is the most vigilant defender the Imperium has to guard its borders. It operates from remote stations known as Watch Fortresses, each absent from Imperial records, as to the Deathwatch, obfuscation is another moat with which to keep its castles strong.
Each space-borne Watch Fortress is a sovereign domain ruled by its Watch Commander. On his authority, entire sectors are put to the torch without question. These strikes are so effective that the grand crusades of attrition which typify humanity’s approach to war are made unnecessary — many growing threats are contained and expunged before the wider Imperium is even aware of them.
Each Deathwatch stronghold operates under a shroud of secrecy, standing as a hidden sentinel over a select area of the Imperium’s dominion. Some are space-borne fortresses that monitor a specific threat — i.e. Castilos Nullifact watches for the rise of the long-slumbering Necron dynasties in the north of Ultima Segmentum, whereas Fort Pykman monitors the Ghoul Stars and the horrors that lie beyond. Others instead keep watch over a specific area in which aliens have been sighted in great measure. There are those smaller outposts called “Watch Stations” which house a garrison of only a handful of Battle-Brothers, whilst the largest of Watch Fortresses play host to entire Watch Companies. Regardless of size, these space stations bristle with weaponry — islands of sanity and strength in the midst of the endless sea of stars.
Watch Fortress Hellsong is orbiting the planet Kishdoc, in the Kishdoc system in the Virago Sub-sector, close to Fenris and the Nachmund Gauntlet.