Keeper
The Deathwatch Keeper are Space Marines that are attached to the Deathwatch, the Chamber Militant of the Ordo Xenos of the Inquisition. Where most Space Marines who serve with the Deathwatch eventually return to their parent Chapters, the Keepers' service is for life. Hardcore.
Overview
These Space Marines are mostly seen on Watch Fortresses and stand watch over forbidden sites where they barred entry to such locations from their Battle-Brothers as well as guarded captured Xenos prisoners for 'interrogation' and 'experiments'. Their duty is held to such heights that even Inquisitors are unable to pass a Keeper without authorization from the Watch Commander. Yes, you hear us right, the nigh-omnipotent Inquisition has to ask for permission to even get past a Keeper. Awesome.
The reason Inquisitors are forced to be compliant is that they fulfill a holy duty to guard sacred or profane objects that fell into the care of the Deathwatch. Amongst the Chapters, this position is normally undertaken by Librarians, Techmarines, or Chaplains, but the small number of such posts within the ranks of the Deathwatch mean that they are too strained to be entrusted with such duties. Thus, the burden of this position is given to Battle-Brothers who have served a decades-long watch and given the important tasks of the Chamber-Militant, ranging from guarding Xenos prisoners to escorting a kill-team on board a starship. Certain regions require the deployment of a permanent detachment of the Deathwatch, which means the selection process of Keepers is crucial, as they are required to stand watch for a decades-long vigil at the edge of madness. Among the most highly trusted of all positions given to Keepers is to serve as host and guardian of either Imperial or alien doomsday weapons that are locked away in Deathwatch vaults. These duties do not restrict them from field duty as they can also be detached and sent with a kill-team. The lore and secrets available to them can be crucial in helping capture a xenos specimen, making them valuable comrades to their Battle-Brothers
Those Astartes chosen for elevation to this position are required to hold an unblemished record of service to the Deathwatch. Following acceptance, the supplicant faced a lengthy period of prayers and fasting before presenting themselves to the Watch Commander and his most trusted advisors. During this moment, the Space Marine is questioned in a long and gruelling manner with psychic probes from Librarians being used to test the potential Keepers loyalty. Temptations are provided at every opportunity until the Watch Commander is completely assured that the supplicant is completely dedicated in every fiber of his being to the Emperor and the Deathwatch.
Not all, however, passed this test with some being destroyed and even succumbing to madness in the process. In some cases, the questioning reveals deep flaws in the supplicant that are destroyed before they can spread to others in the Deathwatch. Among some, no flaws are shown but the Space Marine demonstrates a lack of determination that is needed for the role. But once convinced of their loyalty, a Watch Commander ascends the Astartes to the post of Keeper.
The initiation ceremony involves undertaking terrible and binding oaths where the newly appointed Keeper places the protection of the Deathwatch's secrets first and foremost. After this moment, the Watch Commander locks a vambrace on the right arm of the new recruit known as the Clavis which both symbolically and practically binds him to his new duties. This relic of the Dark Age of Technology is linked to his nervous system and vital signs, which means it cannot be used by another being and even deactivates when its wearer is no more. It can only be reactivated by the correct codes given by a Forge Master. The use of a Clavis allows a Keeper to open the many locks and shield barriers in Deathwatch facilities or control the auto-defences or even activate a vessel's command chapel and stir its Machine spirit. When attached to a Kill-team, the Clavis is detached and left in the care of the Forge Master until the Keepers return. Keepers are firstly veteran warriors with many long years of service that mark their records.
Typically, onboard the Watch Fortresses, they are equipped with ceremonial weapons and armour in order to highlight their status to others. These include powerful glaives, double-bladed chain blades, or even ancient las-lances. Their robes hold embroidery that covers their armour except for their helm and shoulder guards. Their hallowed power armour is amongst the earliest of its kind and holds the Imperial Eagle or Deathwatch icon which includes sigils in High Gothic.