Deathwatch

Like the other orders of the Imperial Inquisition, the Ordo Xenos has its own Chamber Militant; the Deathwatch Space Marines. Across the galaxy there are alien civilisations that threaten Mankind, from the green-skinned Orks to the monstrous Tyranids to the spectral Necron and their C'tan masters. It is the sacred task of the Deathwatch to stand sentry against these xenos races. They are ready to act should such ancient evils ever rise against Mankind once more. The Space Marines of the Deathwatch form the first, and often only, line of defense against these inhuman horrors. Unlike other Space Marines, the Deathwatch are not a separate Chapter of the Adeptus Astartes; rather, they are a collection of Veteran Space Marines drawn from all of the different Chapters who serve together in the Inquisition's service for a period of time. To be chosen by one's Chapter to serve in the Deathwatch is a great honour for any Space Marine, as only the most elite and experienced members of a Chapter are ever chosen for this extremely hazardous duty. Deathwatch Space Marines do not usually form the standard tactical groups like squads and companies generally used by the Astartes. Instead, they tend to operate more like special forces units as small, close-knit groups of specialists called Kill-Teams. If a xenos threat is particularly dangerous, several Kill-Teams may be assigned to deal with it, but if the threat is still too much for even the Deathwatch to handle, the Inquisition will be forced to turn to a full Space Marine Chapter or to multiple regiments of the Imperial Guard to deal with it. In general, if a group of Deathwatch Kill-Teams cannot deal with a xenos incursion, that means that the Imperium has a major conflict on its hands.

History
The origins of the Deathwatch are uncertain, but following the arrival of the Imperial frigate Eisenstein at Terra at the start of the Horus Heresy when a contingent of Loyalist Space Marines from the Traitor Legions came to Terra to inform the Emperor of Mankind that the Warmaster Horus had betrayed him at Istvaan III and been corrupted by Chaos, it is implied that Captain Nathaniel Garro and his Loyalist Death Guard Space Marines, along with Captain Iacton 'Half-Heard' Qruze of the Luna Wolves, will be folded into a new Imperial organization at the instruction of the Emperor of Mankind that sounds very much like the Imperial Inquisition. While not definitive, it seems likely that the Loyalist Death Guard Space Marines formed the initial core of the Deathwatch, hence the name of the organization.

Organization
As the Chamber Militant of the Ordo Xenos, the Deathwatch is tasked with the study and, if necessary, the extermination of dangerous intelligent alien races encountered by the Imperium. They are also tasked with the observation of alien races, and the acquisition of their technology for further study by the Adeptus Mechanicus. This is because the Deathwatch are not merely intended to cleanse xenos cultures from Imperial space. They are also tasked with the recovery and study of alien devices and artefacts. Sometimes it is necessary to use a weapon against the enemy who created it, although this is not taken lightly. The Deathwatch are constantly vigilant for sabotage, or to advise if it is truly safe to use a weapon of xenos origin. The Adeptus Mechanicus are always on the lookout for alien technology; for instance, the C'tan Phase Sword, used by the Callidus Assassins, was recovered from a Necron Tomb World and successfully integrated into the arsenal of the Imperium.

The Deathwatch are uniquely organized in that the Veteran Space Marines that make up the Deathwatch are drawn from many different Chapters. They are then specially trained in small units called Kill-Teams to counter xenos threats and are sworn to serve an open-ended term with the Deathwatch. When they return to their Chapter of origin, the former members of the Deathwatch take their hard-won knowledge with them to share with their Battle-Brothers, as well as supplies of specialist anti-alien weaponry.

The Space Marine Legions and subsequent Second Founding Successor Chapters were bound by an ancient oath to provide troops to the Deathwatch. However, particularly among some of the more radical Space Marine Chapters, this can be a great test of duty, especially for those like the Dark Angels or the Black Templars that see the Inquisition as corrupt and an enemy of the rightful independence and autonomy of the Adeptus Astartes.

Although there is no question of any Chapter or Space Marine failing to fulfill their ancient pledges, Chapters like the Iron Hands, Dark Angels, Space Wolves and Blood Angels have a notoriously strained relationship with the Inquisition. It is not unheard of for Radical Ordo Xenos Inquisitors to find the secondment of Deathwatch troops to their command facilitated by aiding one of these Space Marines Chapters against the political machinations of a Puritanical Ordo Heriticus Inquisitor.

Other Chapters such as the Ultramarines, Crimson Fists and Imperial Fists have a far closer relationship with the Inquisition as a whole and the Ordo Xenos itself. Space Marines from these Chapters are more frequently and in greater number inducted into the Deathwatch, although a Kill-Team may be made up of any variety of Marines as the resources of the Ordo Xenos Chamber Militant are moved around the galaxy. The Space Marines making up a Deathwatch Kill-Team can vary hugely in personal philosophy, culture and custom but are bound together by their loyalty to the Emperor and their zealous hatred of the alien enemies of Mankind. A Space Marine will remain with the Deathwatch until the Inquisitor leading the detachment deems that the necessary tasks have been completed so that he may return to his Chapter with honour.

Combat Doctrine
Deathwatch Space Marines will usually operate in individual Tactical Squads, known as Kill Teams. Each Kill Team will be led by an Inquisitor, Brother-Captain or Librarian. Their missions range from those undertaken alone and without support, attempting to accomplish their goals with minimal combat engagement; to open battle re-enforcing allied forces like the Imperial Guard, Sisters of Battle or other Space Marine Chapters against alien incursions.

The highly perilous and vital nature of their missions means that Deathwatch Kill-Teams have access to exceedingly rare or advanced Imperial equipment, such as Heavy Bolter Gyro Suspensors, M.40 Targeters, and numerous types of specialist ammunition, such as the fragmentation Metal Storm shells or the high-powered Kraken penetrator bolts. If the situation offers no alternative, they will utilize advanced alien weaponry and equipment to accomplish their mission. The Deathwatch often utilises unconventional means of insertion, such as teleportation, high altitude grav-chute drops and Demiurg Termite tanks.

Sometimes, the situation may be more than even a dozen elite Space Marines can handle, and because of this, Deathwatch Space Marines are able to freely requisition any and all Imperial forces they deem necessary to complete their task, from individual Brother Space Marines of other Chapters to entire regiments of the Imperial Guard. A member of the Deathwatch speaks with the full authority of the Inquisition and also possess the unlimited (in theory) authority of that organization and its servants.

Appearance
When a Space Marine is granted the honour of becoming a member of the Deathwatch, he will ritually repaint his Power Armour black, regardless of the original Chapter colour scheme. As it is believed to be an insult to the armour's machine spirit if the armour is completely repainted, the shoulder plate bearing the original Chapter's badge is left untouched and is moved to the right shoulder. The now vacant shoulder is covered with an ornate Deathwatch Chapter badge (the Inquisitorial I with a skull in its centre superimposed over lines of text) and the whole of the left arm and shoulder guard are painted silver.

Notable Deathwatch Characters

 * Artemis, Battle-Brother - Artemis has the ability to sense and recognize alien incursions and influence. He was originally of the Mortifactors Chapter but was brought into the Deathwatch to put his abilities to use. Artemis commanded Deathwatch Kill-Teams against the K'nib in the Donorian Sector. This was done at the request of the Kaslon Imperial Guard Regiment. Artemis personally slew the K'nib Alcayde and ended their attack upon Imperial space, even though the credit was given to the Kaslon Regiment . He is quoted as saying: "Do not ask, 'Why kill the alien? rather, ask, 'Why not?'" His model was released for the Inquisitor game and represents the Deathwatch there. He has his Space Marine Bolter, a Power Sword, an assortment of grenades, and his Power Armour as his equipment.


 * Uriel Ventris, Captain of the Ultramarines 4th Company - An ex-member of the Deathwatch who replaced the captain leading the Fourth Company when he was killed during the defense of Tarsis Ultra from the Tyranids. Uriel Ventris led his team into a Tyranid hive ship to kill the Norn Queen with a gene-poison derived from a Lictor, which was genetically-engineered to induce hyper-evolution in any Tyranid affected by it. He was later exiled from the Ultramarines for breaking the Codex Astartes, condemned to fulfill a death oath.
 * Cyrus, Scout of the Blood Ravens In Dawn of War II, Cyrus says many times that he served with the Deathwatch for nearly two centuries, notably in the Genestealer Outbreak on Victoria Primus.