"I've always liked a good fortress: given one to sit in, most enemies are happy to stay where you might find them easily, and sleep soundly in their beds as you slip in to eat out their hearts."
- —Lady Miram Saynay, Epicure & Corsair Captain
Its orbital stations house key command and control elements for the crusade fleets, a naval repair and provender base, and the crusade's primary Astropathic Choir.
Karlack is also the keystone in a wide arc of listening posts and defence stations known as the Iron Collar spread out across the portion of the Jericho Reach bordering the Well of Night, from which the crusade's salients are supported.
The Fortress World's perimeter is littered with defences. The first layer of fortified space is a sphere of mechanised battle stations, their augur arrays constantly scanning the void. A few track on-going vessels with their plasma batteries as they pass.
These jagged spires and gargantuan orbital platforms berth everything from gleaming new fighters to the war-ravaged skeletons of cruisers who survived battles their crews did not.
Supply stations, more advanced sensorium arrays, and voidfaring troop barracks orbit closer to the faded greyish-green planet. Karlack's sky and atmosphere are thick with the smoke of industry and clouds of dirt thrown up by the ongoing construction.
Once clear of the brackish cloud layer, the landmasses are patchworks of bare earth, dull armoured fortifications, and the occasional stretch of green farmland where fast-growing crop strains are continually planted and harvested for processing into rations.
Karlack's climate has grown unstable due to the alteration of the planetary surface coupled with the rapid industrialisation and forced agriculture methods employed to feed the crusade's forces.
Karlack's seas and air are slowly being poisoned, its people increasingly suborned to the war effort, indentured and outcast on their own world.
This has led, in turn, to an increasing "resistance" movement in some outlaying areas, which has slowly gathered strength despite heavy-handed attempts to crush it by the Departmento Munitorum enforcement cadres.
These factors might turn sporadic civil unrest and incidents of sabotage -- at the moment, a minor thorn of irritation for the crusade forces -- into something far worse.
"Just as they who do not do their duty are not remembered, so too will we be forgotten should we fail. In the annals of history let it be recorded that on this day and at this time, His most divine light shone once more onto this world, shrouded in darkness and hidden from His sight for these four millennia gone."
- — First entry in the annals of the grand conquest of Karlack, meme-scribed 779.M41
Karlack now maintains the single most powerful concentration of the Imperium's military might in the Jericho Reach. Yet in the lost days of the old Jericho Sector, Karlack was little more than an outlying, largely unremarkable colony world.
Its population never rose high enough to make it a power in sector politics, nor did it possess resources of sufficient calibre to make it of particular interest to the Adeptus Terra. When the sector's "Age of Shadow" came, Karlack's relatively marginalised status protected it somewhat and cushioned its slide into isolation, sparing it much of the war and disaster that stalked worlds closer to the sector's core.
Over the centuries, it descended slowly into pre-industrial feudalism. After the discovery of the Jericho-Maw Warp Gate, Karlack's fate was decided by a simple expediency of stellar geography: it was the closest life-sustaining system of any strategic worth in the Jericho Reach in proximity to the Warp Gate.
Thus, it was the first system on which Lord Militant Tiber Achilus set his eye. The mass forces of the crusade were welcomed with open arms by Karlack's natives whose local culture had long kept alive the hand-me-down traditions of the Imperial Creed and the mastery of the Emperor.
The crusade's Adeptus Ministorum contingent quickly set about bolstering that faith and rooting out heresy and corruption in the population. Mountains were swiftly levelled to provide raw materials, rolling steppe land planed into mustering grounds for tens of thousands of troops, and vast fortifications raised both on the ground and in orbit.
Not to be outdone, the Adeptus Mechanicus hollowed out orbiting asteroids into gun-stations and crafted orbital docks to serve as the crusade's primary anchorage. Since this time, Karlack has remained the primary seat of the crusade's power and the principal rallying point and supply hub for the Imperial forces in the Jericho Reach.
In 817.M41, investigations into the disappearance of one Inquisitor Zaer Vincent of the Ordo Xenos drew the attentions of Inquisitor Adrielle Quist to the planet. In so doing, the Deathwatch would be sent to uncover a terrible truth hidden beneath the heart of the Achilus Crusade.
Inquisitor Quist arrived aboard her starship the Angelus Invictus alongside her Vindicare Assassin and protector, Nihl Zee, as well as a Deathwatch Kill-team. Landing at Citadel Primaris, she would be greeted by Lord General Castus Iacton and a dozen guards in black flak armour.
According to Iacton, Inquisitor Vincent had left behind a lacquered box for the Lord General to deliver, under the strictest orders, into Quist's keeping. Sealed behind a small, adamantine vault, the box had been held shut by a series of warded locks even more diabolical than the one on Iacton's safe.
Though Quist was able to bypass them, it turned out to be a trap, as the box contained nothing save a virulent contact poison laced into its seal mechanism. With the attempt on her life, the Inquisitor is forced into the care of the Citadel's medicae staff under the watchful eye of Nihl Zee.
While she recovered, the Kill-team was sent in her stead to find her would-be killer as well as continue the mission.
"Let this moment mark the turning of the ages. We return the Emperor's light to this planet as we return it to this shadowed Reach. This fortress will stand as a monument to the Imperium's immortality."
- —Lord Militant Tiber Achilus at the groundbreaking of Karlack's Citadel Primaris
Tens of thousands of troops and transports stage from Karlack at any one time, regiment upon regiment preparing to replace the losses of an especially bloody battle in one of the crusade salients.
However, in addition to the many bases and emplacements in its orbit, the planet also requires a large, permanent garrison for defence and maintaining order.
Such troops occupy hundreds of stations across Karlack, but the largest, first, and most important of these is Citadel Primaris. Citadel Primaris towers like a mountain above a plain of levelled earth. Observation decks and weapon emplacements jut from the sloping walls at regular intervals.
Ships ranging from Valkyrie transports to Marauder bombers can land on one of the immense duracrete pads, leading into a large gravel yard that lies beyond the high walls. In general, several squads perform drills here under the watchful eye of a Commissar.
Cenotaph of Achilus
Rebuilt in monolithic, glittering grey-black marble over the ruins of a former Imperial cathedral destroyed during Karlack's Age of Shadows, the Cenotaph of Achilus towers over the capital city of Kar'thir.
This monument was constructed in the centre of Karlack's largest indigenous settlement as a grand tomb, intended to stand forever empty of its planned occupant, the Lord Militant. However, the Lord Militant's untimely death made this cenotaph a shrine to the crusade's first master.
It also serves as a place of devotion for its soldiers and a memorial to the fallen. The names of the lost are engraved into its soaring vaults and chambers, and many believe the Cenotaph to be the spiritual heart of the Imperial war effort.
For those who have come to see the Imperial presence on Karlack as a curse rather than a blessing, however, it is the greatest symbol of their oppression and woe.
City in the Sea
Considered little more than a local myth by most, the wide ocean that covers much of Karlack's southern hemisphere is said to contain a mysterious sunken city. There, the tormented spirits of the dishonoured dead are said to be dragged by dark-robed spectres amid its drowned towers and darkened ziggurats, to be devoured for all eternity.
All ill-fortune and disaster experienced by the people of Karlack are assigned to this watery underworld, and those natives that live on the scattered islands of the south are viewed with deep suspicion by their fellows.
Myth or not, the construction of strategically necessary defence structures and orbital batteries on the southern island chains have proven deeply problematic for the crusade forces on Karlack.
The problems stem from both local resistance and the high frequency of unexplained accidents, disappearances, power-outages and equipment failures experienced in the southern ocean zone.
Inquisitorial investigation in the area -- communicated to the Deathwatch for verification -- has failed to discern a direct cause for the incidents. However, the Inquisition's reports have revealed these problems to be steadily increasing over recent months.
They have also turned up previously unknown examples of non-Human artefacts of ancient age amongst the construction on the islands. These artefacts feature strange mathematical and geometrical patterning that have caused great concern amongst the Ordo Xenos. Until recently, Inquisitor Zaer Vincent presided over the investigation.
However, the Inquisitor went missing at the beginning of 817.M41, and he is presumed to have been slain. The Deathwatch have taken a keen interest in how matters develop here.
- Deathwatch: The Achilus Assault (RPG), pp. 14, 345-346
- Deathwatch: The Emperor Protects (RPG), pg. 52, 56-57