Dark Krakens - Cordon Impenetra: With the savage conflict known as the Octarius War between the Tyranids and Orks of the Ork Empire of Octarius spilling over into the Pankallis Sub-sector in the Era Indomitus, Space Marine Chapters have raced to the region's aid. Among these were the Dark Krakens. A powerful assemblage of these transhuman warriors fought to defend the Bianzeer's Hollow System against the Tyranid swarms.The Pankallis Sub-sector borders the Octarian Empire, Ork-held space that has been fought over by greenskins and Tyranids for many standard years. A part of the so-called Cordon Impenetra established by Inquisitor Nashir Sahansun to protect the rest of the Imperium from that deadly fight between the two alien species, the Pankallis Sub-sector was in the midst of preparing for xenos invasion when attacks came without warning.Now the xenos had finally arrived, and they had to be halted lest they break out of the Cordon Impenetra and push into the Imperial star systems beyond.By luring a tendril of Hive Fleet Leviathan into the Orks' Octarian Empire during the Third Tyrannic War, former Inquisitor Fidus Kryptman sought to have the two xenos hordes destroy one another. However, his plan backfired. The Tyranids were fed with incalculable quantities of biomass and genetically adapted to countless kinds of new and different threats, becoming even stronger.The huge scale of the conflict, which claimed millions of Ork and Tyranid lives each solar day, drew in ramshackle greenskin fleets from light years around, and the Orks themselves grew bigger on a diet of endless conflict.Many Imperial observers believed that it was only a matter of time until the roiling conflict spilled out into neighbouring Imperial systems and inflicted untold damage. One of these was Inquisitor Nashir Sahansun, who devised what he called the Cordon Impenetra. Drawing a sphere around the outer reaches of the space fought over by the Orks and Tyranids, he declared almost every Imperial world within the zone of demarcation lost, and he pushed hard for every sub-sector bordering the boundary to fortify itself and be reinforced.Many worlds in the region joined the Cordon Impenetra, which both served as a man-made boundary and was the name given to a defensive organisation made up of worlds along the border. As the worlds of the cordon were reinforced, efforts were made by Imperial troops to destabilise the warring xenos forces to ensure that neither concentrated their strength sufficiently to break through the cordon. Ultimately, these actions proved to be in vain.When the Pankallis Sub-sector was attacked, every invaded star system called for aid, and multiple forces responded. Deathwatch from the Eye of Octos Watch Fortress and Primaris Marine warriors of the Wolfspear Chapter were among the first to arrive. They were followed by a large strike force of warriors from the Dark Krakens Chapter under the command of Chapter Master Mezonyki Reio.Reio dispatched his warriors to all three planets in the Bianzeer's Hollow System, tasking Captain Krijeni Luceior and the 5th Company with fighting the Tyranids on the unusually named planet Death of Bianzeer. This frozen Death World was the furthest planet in its system from its star.After arriving in Death of Bianzeer's orbit, Captain Luceior swiftly partook in a council of war with other Imperial commanders. It included Battle Leader Rakmeyr Bluewolf of the Wolfspear, Watch Master Akrep Xie of the Eye of Octos Deathwatch and Lord General Militant Arneld Heifaast, commander of the Astra Militarum troops stationed on the planet.Before the Dark Krakens' arrival, much had happened, and much had gone wrong. The Wolfspear had slaughtered a huge horde of Tyranids by causing an avalanche that drove all the creatures that survived into the world's Mirror Sea. However, the resulting tsunami destroyed the access point for the promethium rigs on the sea's bed. On the frozen Great Lakes of Peldathusa, thousands of locals had driven swarms of Tyranids onto the weakest part of the ice, sending countless Tyranids into the freezing waters.Despite the apparent victory, many Tyranids survived the extreme temperatures, bursting out from the lakes and devouring the people who had orchestrated the trap. More mysteriously, troops from the Death of Bianzeer Trackers planetary defence militia had observed Tyranids stalking packs of the native ursun-wolves in the Herrdalo Forests north of the world's equatorial permafrost.The wolves were highly intelligent, pack-hunting alpha predators with instinctive knowledge of the local terrain and where Human settlements lay. Their genetic material would be of great value to the hive fleet.Leaving five squads with his ships under the command of Chaplain Talin and Codicier Ekko, Luceior deployed the rest of his forces to the surface. His intention was to engage the Tyranids in the Herrdalo Forests, drive them from the area and therefore stop them from consuming the ursun-wolves. Though it was an unorthodox mission for them to protect wild beasts, if the Tyranids wanted something, Luceior was determined they would not be successful. Success would also mean pushing the xenos away from the world's methane pumps and relays.When additional reports warned of Tyranid monsters attacking the now isolated promethium extraction rigs beneath the Mirror Sea, Luceior ordered Lexicanium Uari and Techmarine Eroan to aid in securing them. Deathwatch Kill-teams deployed alongside them. Akrep Xie of the Deathwatch declared that he would aid the Dark Krakens personally in the forests, alongside several of his own Kill-teams.Lord General Militant Heifaast also approved of the plan, committing dozens of Astra Militarum regiments to sweeping the forests clear while planetary defence militia regiments increased their patrols around the permafrost's industrial areas.The Imperial forces fighting in the forests faced harsh challenges from the outset. They had to scale treacherous cliff faces and wade through towering snow drifts, all while at the mercy of the bitter cold. Soldiers plunged through broken ice into freezing pools or were struck by heavy branches as they broke and fell beneath the weight of accumulated snow.This all meant little to the Dark Krakens. They had slain beasts three times their size on their homeworld of Naktis' ocean floor. On a hundred and more battlefields, many had fought all manner of xenos and abominations of the Warp in the most gruelling conditions imaginable. They had all the rugged determination, stubbornness and resilience of their gene-sire, Vulkan, and they put down any and all Tyranids they encountered, most of their squads operating in loose skirmish formations.Incursors followed the barest tracks from both xenos and ursun-wolves alike, leading Intercessors armed with Stalker Bolt Rifles to dens and nests. Reiver squads rappelled over the most arduous terrain whilst covered by the careful aim of Eliminator squads, who picked off beasts with perfectly aimed shots as ursun-wolves or other predators attempted to intercept the manoeuvring terror troops.This did not mean the fighting was straightforward. The Dark Krakens so admired the power of the ursun-wolves that they endeavoured to shield them from the Tyranids and even forbade the Imperial Guardsmen and militia from killing them, though some did so out of necessity.But the ursun-wolves cared little for that fact, and they attacked Space Marines and Guardsmen alike to defend their territory as well as claim prey. Those with young fought especially viciously, and several Dark Krakens were severely wounded or even killed when these predators successfully isolated them and struck en masse.For the Tyranids' part, broods of Hormagaunts burst from piles of snow, savaging Imperial Guardsmen and bowling into the Space Marines. Lictors emerged from hidden tunnels and cliff overhangs behind and amongst the Dark Krakens, inflicting many casualties before being brought down. Gargoyles hung perfectly still from the highest tree branches, only diving down to attack the Space Marines once the Adeptus Astartes had advanced past the trees they were hidden in.Dark Krakens and Tyranids fought bloody running battles through the forests as the xenos surged against spread-out Space Marine squads. The xenos threatened to break through Imperial lines on multiple occasions, only to be stymied at significant loss.The campaign became increasingly protracted. The ursun-wolves knew their territory well and fought ferociously to defend it. The Tyranids were equally unwilling to cede ground, launching countless raids and counter-attacks that stalled the Imperial advance across the entire front. To force any advance at all in some areas against the aliens, Imperial forces called in continuous Aeronautica Imperialis bombing runs.Marauder bombers dropped countless tons of incendiaries and mole bombs that bored several metres down before detonating. There was no simple way to achieve victory, no single foe to slay that would signal the end. The campaign was pure attrition. Fresh waves of troops were sent behind the first to ensure that cleared areas remained clear.Wherever the Dark Krakens fought, the advance moved more quickly, the Primaris Space Marines slaughtering the toughest enemies and inspiring the exhausted mortal troops who had become anxious and disquieted by the ever-present threat of ambush.The Space Marines were utterly resolute in their task. Just as stalking a megabasilosaur in the depths of the Kesuramir Ocean of Naktis required patience, this was no different. Success meant outlasting their foe and meeting its displays of strength with even greater might of their own.The Dark Krakens were as an adamantine tidewall against a ship-breaking storm. They threw back the Beast-surge of the Glonhil Valley, emerged bloody but victorious after the Night of a Hundred Horrors and held the line after five companies of the 602nd Truskan Snowhounds vanished without a trace. Even as the Space Marines' casualties mounted, they did not waver, spurred by the fiery zeal of Reclusiarch Zitadan.It was many solar months before the first Imperial forces reached the forests' northern boundaries, having finally pushed the Tyranids out. It had required more than four dozen regiments of Astra Militarum and the combined efforts of the better part of a Dark Krakens Battle Company and several Deathwatch Kill-teams. Even then, some forces fighting in other parts of the forests still had much further to advance, their progress hampered by harsh terrain and vicious fighting.Captain Luceior would only declare the mission complete when every Tyranid was driven from the forests. He was drawn away before he could. Word came from Deathwatch Kill-teams elsewhere on the planet. A huge Tyranid swarm was descending on the half-complete Glacialix, a colossal fortress under construction by the Adeptus Mechanicus close to several of the planet's larger population centres.Watch Master Akrep Xie immediately pulled his Deathwatch forces from the Herrdalo Forests. Knowing the strategic importance of the citadel, Luceior deployed some of his warriors to defend it, joining them himself.