Within the span of a few Terran weeks, Ork-ridden battleships reached the outskirts of the Sentia system, unloading shells and energy weapons into any hapless vessels they came across. Half a billion kilometers away, the propulsion thrusters of the Blade of Eternity thundered to life, as the stately craft and its compliment of strike cruisers slowly moved to intercept the growing ork armada. Vastly outnumbered, the space marine commanders of these vessels waited until the orkish fleet came within range of the orbital weapons platforms of Sentia before launching their counter-offensive, all in a hopeless attempt to keep the orks offworld. As the weapons platforms silently poured heavy las-fire and missles into the enemy fleet, the skeleton crew of space marines sent forth every frigate and thunderhawk docked in the their fortress to hold off the assault. However, they knew the futility of this effort, such was the vastness of the force arrayed against them.
The Blade of Eternity fought valiantly, claiming a score of Ork battleships before its voidshields overloaded and failed. To lose the fortress, with its gene banks and data-archives, would seal the Shadow Guardians’ doom, and it would need to survive if any meaningful counterattack were to be launched after the main elements of the chapter fleet returned home. Thus, with shame in their hearts, the Shadow Guardians withdrew the Blade of Eternity from the field of battle. With what few strike cruisers and gunships remained operational, the Shadow Guardians escorted the venerable fortress monastery as it made for the far side of a nearby asteroid field to assess its damage and re-establish void shields. Smaller ork fighters and ramships gave chase, but were quickly mopped up by the formidable skill and firepower of the Shadow Guardians.
Luckily for the chapter, the attentions of the orks quickly reverted to the weapons platforms as more and more battleships and kill-kroozers fell to the disciplined las-shots of the PDF. The orks were undeterred by their grievous losses, intent as they were on pillaging this feeble human world, they would salvage their burning wrecks and cobble them back together in due time. One by one, the defensive platforms fell before the horde. Somewhere in the turmoil, orks must have captured a weapons platform or imperial vessel, as the howling roars of the WAAAGH echoed across the imperial communications network, sewing fear and despair amongst the ranks of the PDF. Soon, massive landing craft teaming with greenskins careened toward the continental glaciers of Sentia Primaris. Upon landing, mekboys and their gretchin crews set to work erecting massive teleportation devices to spew forth the main bulk of the orks’ battlewagons, kans and other machines of death waiting eagerly within the holds of the ork battleships above. With terrifying swiftness the mobs of orks gathering around these rudimentary war camps became a characteristic green tide of boyz looking for a good scrap with the Emperor’s finest before salvaging as much metal as possible to build new kill-kroozers for the warboss’ growing fleet.
The hive cities of the Southern pole were overrun in a matter of days. Yet in the north, the human populace waged a fierce war over land, air and sea, augmented by a small Shadow Guardians task force. Having evaded the orks’ sloppy blockade, the Shadow Guardians bolstered the PDF’s defenses significantly by ferrying dozens of tanks and other weaponry to the surface via thunderhawk and drop pod. The few Adeptus Astartes available to fight on the ground stood shoulder to shoulder with the brave men and women of Sentia, ready to sell their lives dearly to stall the attackers until reinforcements arrived. Unbeknownst to the Shadow Guardians, the Planetary Governor had called up scores of civilians with psychic powers to join the war effort in a more extreme capacity. In a secret moment of cowardice and desperation, the governor ordered the few sanctioned imperial psykers stationed on Sentia to “train” these gifted individuals in the full use of their powers, that they might turn the tide of battle in humanity’s favor, or at least buy time until the Shadow Guardians’ main fleet had returned to the system.
The bulk of the chapter finally arrived after a series of increasingly daring shortcuts through the warp to hasten their return. Upon reaching their ancestral home, the Shadow Guardians found the Blade of Eternity badly damaged from its engagement with the enemy, and the planet’s orbital defense matrix in tatters. Planetside, the smaller continents of Sentia’s southern hemisphere had been overrun by the Green Tide, with the remaining PDF and Astartes forces pushed nearly to the breaking point securing the hive cities and manufacturing centers of the northern polar continents. As six full companies of space marines made planetfall, the Shadow Guardians’ chief librarian, Locrius intuited a strange presence in the warp, clouding his thoughts with a sense of impending doom. It would be 72 hours of brutal warfare before this dark presence revealed itself to the battle-hardened psychic.
The fully reinforced marines now set upon their ancient foe with a righteous fury worthy of legend. Everywhere they trod, orks died by the hundred. Honored veterans in mighty terminator armor, equipped with hammer and stormshield smashed through orks and their war machines. Armored columns of tanks supported by PDF aircraft struck at the most heavily armed and armored components of the advancing foe attempting to slow their advance on the hive. Dreadnoughts of every classification fired upon the mobs and their battlewagons until their magazines were utterly spent, and then charged headlong into the foe, grinding them into the churned ice. In the black firmament above, the battle barges and strike cruisers of the Shadow Guardians fired every weapon at their disposal into the ork fleet. Piercing lance fire sliced through ork super-battleships whilst marines loaded in Caestus assault rams staged perilous boarding actions to sabotage several of the ork frigates.
Victory, however, would prove elusive to the valiant defenders of humanity, for just as the tide of battle turned firmly in the Imperium’s favor, at least eight confirmed warp anomalies appeared on the surface of Sentia Primaris. From these unholy portals streamed forth all manner unspeakable horrors, corrupting and slaying the remaining Planetary Defense forces and civilians in equal measure. At this moment the chapter’s ground forces had been steadily advancing at the vanguard of a sweeping assault across the northern glacial plains toward the ork-held coastline. They now found themselves trapped along with several platoons of PDF between the xenos horde reinforcing from the southern sea and a new foe spilling out from their own cities to the north. Chaos had come to Sentia, and would claim this world, or see it scoured of all life. Subsequent Inquisitorial investigations would reveal this Chaos presence to be an army led by a Lord of Change, a Greater Daemon bound to the will of Tzeentch. Likely it came to Sentia in order to claim the high number of psykers as vessels through which Tzeentch would work its dark sorcery upon the Imperium of Man. The portals used by the Chaos war host were eventually revealed to be several of the unsanctioned psykers themselves, now ripped open by the forces of Tzeentch. These poor souls, trained only briefly in the use of their powers for war, were untested and underprepared for the perils of the warp, and provided the Lord of Change with an unlocked door through which it would pour forth its madness upon this icy world full of psychic potential. Perhaps it had jealously observed this jewel of a world for millennia, gradually bending fate to bring about this very sequence of events.
Within 24 hours of the Chaos outbreak upon Sentia, the Black Ships of the Inquisition appeared in the system, ready to perform exterminatus upon the war-torn sphere if needed. A full Sisters of Battle company arrived hours later. At the Inquisition's command, they gained control of what little defensive structures remained in orbit after weeks of battle against the now-routed ork starships. At the behest of the Inquisition, the Sisters established a perimeter around Sentia, helping the Shadow Guardians to drive off what remained of the Ork fleet while ensuring that no ships could enter or depart Sentia’s atmosphere. Gleaming, ostentatious transports of the Sentian upper class could be seen occasionally rising out of hatches in the tops of the Northern hive spires, but the Battle Sisters’ blockade sent these back to the surface in flames. The Planetary Governor, along with most of his staff, probably met an ignoble end aboard such a craft, for he was never heard from again.
In this radically changing warzone, the Shadow Guardians exemplified the true tactical brilliance of their primarch, Roboute Guilliman. Their inspired usage of the Codex Astartes showed as never before. Cut off from further reinforcements from above, the planet-bound battle brothers swiftly divided into two forces tailored to their separate roles. One force mounted in Thunderhawks and Storm Eagles would race to the various warp portals to meet the Chaos threat, their librarians hoping to seal these tears in the fabric of realspace, and staunch the flow of Warpspawn over their beloved homeland. The second force would press southward through the frozen wastes, its flank protected from chaos ambush by landraiders and dreadnoughts. The goal of this second force was to engage in a series of daring hit and run skirmishes against the scattered ork mobs. Using assault squads and landspeeders, the chapter hoped to incite the orkish horde to remount its offensive, ultimately baiting them into battle with the forces of Chaos if possible.
During the next desperate hours, Shadow Guardians Chapter Master, Lord Hesiod himself, parlayed with the council of Inquisitors overseeing the Sentian quarantine, in a bid to save what little remained of this planet’s people and culture. It was Hesiod’s plan to use the insatiable battle lust of the Orks as a distraction for the Chaos warriors while the Shadow Guardians’ air support escorted transports filled with refugees up to their fortress monastery, away from the powerful clutches of Tzeentch. However, it was clear to Lord Hesiod that the Inquisition and Ecclesiarchy now viewed this system’s psyker-heavy populace as more of a liability than an asset. Predictably, the Inquisition mulled Hesiod’s rescue plans over for a time before rejecting them in favor of the more cautious approach of exterminatus, ensuring no Chaos taint would linger here as a viper in the weeds, waiting to strike at the Imperium with an army of corrupted psykers. This would need to be done quickly before the warp anomalies increased in size to create a permanent warp incursion into realspace within the system. The Inquisitorial council made one concession to the imploring chapter master, and that was to allow a final 36 hours for the evacuation of all space marines and their valuable war materiel from the surface of the planet into the custody of the Inquisition, that they might be inspected for any latent signs of Chaos corruption.
Furious, but ever loyal to the will of the Imperium, Lord Hesiod returned to his flagship to take counsel from his most trusted advisors on how to handle the next few hours as Inquisitorial ships began to move into key positions around the doomed world. As Hesiod relayed the Inquisition’s orders to his ground forces, Chief Librarian Locrius defiantly continued to lead the space marines at his command back into the heart of the beleaguered hive spires, splitting the marines into a series of rescue parties, which would use their remaining Thunderhawks and other aircraft to save as many untainted souls as they could gather from the fallen cities. Wave after wave of the planet’s own citizens turned on their defenders, having succumbed to the insanity of Tzeentch. The carnage witnessed in those tunnels was great.
Simultaneously, over half of the remaining Shadow Guardians and the bulk of their tanks, terminators, and dreadnoughts engaged in a fighting retreat from the ork-held coast to draw out their remaining forces and to lead them to the heart of the Chaos menace, so as to buy time for a final escape from Sentia with any survivors their brethren could extricate from the smoking ruins of cities buried in the ice.
Mere hours away from being engulfed by the planet-cracking force of thousands of Cyclone Torpedoes, Locrius rallied his forces on a flotilla of PDF naval aircraft carriers at a secret location in the equatorial oceans of Sentia, far from any land-mass. Thunderhawks and PDF transports heavy with the last uncorrupted members of Sentia’s human populace touched down on the decks of the carriers, unloading a few hundred souls into the holds below. Half a world away, the ground army Shadow Guardians succeeded in luring their age-old, brutish adversary to Chaos’ doorstep. The Shadow Guardians then slipped away from their foes through ancient, hidden tunnels carved through the glaciers to the coast known as the White Gates. The war-torn remnants of the 10th company brought up the rear, ensuring no daemon or greenskin pursued, by detonating charges placed at key points along the tunnels in ages past. A single black transport of the Inquisition descended through the ragged grey clouds, opening its multiple bay doors as it landed. Squads of marines, their remaining tanks and holy dreadnoughts marched solemnly into the black ship, as a bitter wind carried the chittering screams of advancing Tzeentchian horrors over the snowy terrain. As soon as the last dreadnought stepped across the threshold, thrusters roared to life and the blue-white surface of Sentia disappeared beneath grey clouds. The bulk of the Shadow Guardians’ motor pool secure aboard the Inquisitorial transport, Lord Hesiod allowed himself a long sigh of relief. His planet would not survive the next three hours, but his chapter might.
Countless leagues away in the middle of a vast ocean, deep in the holds of the aircraft carriers, Chief Librarian Locrius explained the situation to the refugees in his charge. Hesiod had made clear to his chief librarian that no human would be allowed to leave the doomed world, by order of the Holy Inquisition. Locrius silently cursed the intractable Inquisitors and their lackeys as he gazed one last time upon the dark waves of the ocean before rejoining his cadre of fellow librarians below deck. In an ancient Shamanistic ritual remembered only by the Astartes, they said goodbye to their home, and issued the burial rites to the populace and the planet itself as the people of Sentia had done for their loved ones in countless centuries before space marines ever set foot on the planet. Then, through their combined psychic might, they teleported themselves and nearly four hundred human souls, the last survivors of the Sentian War, offworld to a vault deep within the titanium heart of their chapter’s fortress monastery. Such was the power of the legendary Locrius in those days, that he could carve a path directly through the warp to the heart of his waiting sanctuary and envelope his forces as they moved across it, without the notice of either Tzeentch or the Inquisition, which remained focused on monitoring the growing warp phenomena and carrying out its exterminatus protocols. Aboard the Blade of Eternity, the librarians that traveled with Locrius placed the refugees in stasis chambers until such time as Locrius himself could properly interrogate them for any taint of Chaos. However, Locrius could not be found anywhere aboard the vessel. Quite possibly the most powerful battle psyker in the Imperium at the time, Locrius did not emerge from the other side of this massive exodus through the warp. Legends among the Shadow Guardians say that he either discorporated from the psychic strain of shepherding so many minds through the warp at once, or that, in the last moment, he locked eyes with the Lord of Change himself, and charged after him over the twisting, rushing seas of the warp to sink his mighty force axe into the hide of that fell daemon in the name of the Emperor.
In the final minutes of life on Sentia, several Thunderhawks lifted off from the decks of the abandoned aircraft carriers, taking the remaining Shadow Guardian squads into orbit as Cyclone Torpedoes began to rain down from the Black Ships…