Shadowkeepers

The Shadowkeepers, known also as the 'Wardens of the Dark Cells', are a specialised Shield Host formation of the Adeptus Custodes, the stalwart guardians of the Emperor of Mankind. They are charged with the vitally important task of standing eternal vigil over the Dark Cells, where terrible things are locked away deep beneath the Emperor's Imperial Palace on Terra, eldritch terrors from the depths of Old Night that could annihilate the Imperium.

Background
To the Shadowkeepers falls the duty of standing guard over the Dark Cells, a particularly sequestered and forbidden sub-division of the deep levels below the Imperial Palace complex on Terra, unto the end of time. The Shadowkeepers hold the keys to the rune-locked portals hidden deep beneath the Imperial Palace. They alone know the ways by which the runic locks may be disengaged, the wards unbound and the sanctic circles breached. They alone know that these things must never happen, for the Dark Cells hold such horrors at bay that Mankind's sanity would not survive their release.

A full shield host is devoted to this grim responsibility, over a hundred Custodians patrolling the dark and silent corridors, vigilantly watching over the last terrors of Old Night. It is a task that would soon drive most men mad, for though neither sight nor sound can escape the forbidden cells, the air of those corridors is charged with dread.

A perpetual menace thickens the shadows and makes them crawl. Even the superhumans of the Adeptus Custodes are forever on edge in those dark oubliettes, for the sense of unspeakable threat never wanes. It is a testament to the discipline and spiritual fortitude of the Shadowkeepers that they stand their guard unflinching, sometimes for decades at a time.

The ranks of this shield host include many Custodian Wardens, whose oaths of protection help them to focus upon the task at hand to the exclusion of all else. The leaders of these forbidding sentries carry ancient weapons of mysterious provenance, their use intended as a last resort should anything ever break free from the Dark Cells.

For ten thousand years the Shadowkeepers have performed their duty, yet the coming of the Great Rift changed everything. With the power of Chaos spilling raw and seething into the spaces between the stars, new abominations have come to light. Worse still are the cells that stand suddenly empty, the entities and artefacts once contained within spirited away by some unholy force to curse the galaxy once more. Fearing the consequences of such dread remnants of the Age of Strife falling into the wrong hands, the Shadowkeepers at last sent warriors out into the galaxy. Not since the dark times of the Horus Heresy, when several sodalities of Shadowkeepers deployed as a apart of the Prosperine Censure Host during the Burning of Prospero, has this Shield Host deployed en masse. In this darkest of ages, these jailers must trammel that which should not be, slaughtering all who seek to impede them, before returning their foul prizes to the cells where they belong.

The Lockwarden
There have been many Shield-Captains charged with mastery of the Shadowkeepers. This appointment confers the title of Lockwarden, a name that is borne in perpetuity and garners solemn respect from every other member of the Ten Thousand. The Lockwarden must be the sternest of all guardians, the most unrelenting and alert gaoler on the face of Terra. Moreover, should any creature or relic escape the Dark Cells, or newly emerged threat need to be imprisoned therein, it is the duty of the Lockwarden to personally oversee the operation.

The current incumbent of this position is Shield-Captain Borsa Thursk, who has been Lockwarden for a century and a half. He is a grim and frighteningly intense warrior whose utter fearlessness and steely vigilance make him ideal for his role. It speaks volumes about the dire condition of the galaxy that Thursk left Terra but twice before the breaking of the storm, yet he has barely set foot there since the Great Rift yawned wide.

Notable Campaigns

 * The Ominous Gift (Unknown Date.M33-M39) - Halo-belt augurs reveal the Space Hulk Ominous Gift advancing inexorably out of the dark void towards Terra. Using his status as a High Lord to overrule objections by the Imperial Navy, Captain-General Aesoth Koumadra orders a strike by several shield companies to gut the craft from the inside and ensure its corruption is wholly purged. Those outside the Adeptus Custodes do not understand the significance, but the attack is led by the Lockwarden of the Shadowkeepers and a band of his black-armoured comrades. The Ominous Gift is destroyed - the wider Imperium need never know any more than that.
 * The Years of Madness (Unknown Date.M40-M41) - whispers engulfs Terra, beginning with the disappearance of the notoriously conservative Captain-General Galahoth. Battling the stagnation of Galahoth's rule, the Adeptus Custodes find themselves facing a shocking increase in cult activity - both heretical and xenophile - throughout the Sol System. Doomsday sects trigger queue-wars between the pilgrim tribes within the Emperor's palace itself, and the Custodians are forced to exercise their authority in the bloodiest fights they have seen in centuries. Reports from the Dark Cells cite a growing sense of agitation amongst the hidden inmates, and numerous support servitors have to be destroyed by the Shadowkeepers after they exhibit sudden, violent madness. Worse is to follow as possession is revealed amongst a sub-sect of the doomscryers themselves, though not until the false predictions of the fallen psykers send Captain-General Launceddre to his death at the Battle of the Gilded Pyre. It is amidst this climate of spiralling paranoia and danger that Captain-General Trajann Valoris is elevated to command the Ten Thousand, and he wastes no time in taking steps to regain ironclad control of Terra's defences.
 * Into Shadow (Unknown Date.M42) - Upon the direct orders of Trajann Valoris, a small, fast-moving force of Custodians makes haste for the ruined remains of Cadia. Details of their mission are suppressed, even amongst their comrades, but they are accompanied by a number of warriors drawn from the ranks of the Shadowkeepers.