Crimson Castellans - Defence of Ector: There have been times when the starfaring Tyranid bio-fleets have fallen afoul of Warp Storms, never to appear again. The splinter fleet of Hive Fleet Kraken that was sent head-long into the Empyrean by the Aeldari Seers of Craftworld Iyanden had an even stranger fate.Its bio-ships later emerged from a dimensional rift into the Valedan System (known to the Aeldari as the Dûrien System), deep in the Segmentum Solar. The splinter fleet had crossed the span of the galaxy in a matter of standard years. Worse still, it had emerged right in the path of Hive Fleet Leviathan. At this time, the Crimson Castellan Space Marines were conducting their Landing of the XIV Ascension upon the Hive World of Ector.This was the Chapter's recruitment rite, which tradition and obligation demanded they undertake across five selection worlds every ten standard years. Yet, in the midst of this important event, Valendan's Astropath Prime Hostor Mazurn detected the first signs of the Shadow in the Warp. The coming of a Tyranid Hive Fleet is preceded by a smothering psychic signal that envelops entire star systems and disrupts all forms of Warp travel and communication.This disruption heralded the imminent invasion and horror that was about to confront the Valedan System. It was suspected by the Crimson Castellans that this Hive Fleet was in fact a branch of Hive Fleet Leviathan. It would enter the system periphery within a solar week. They plotted its course as best they could, and believed it would fall first upon the world of Daea, then Megus, Valedor and Ector in turn.Regrettably, the Crimson Castellans knew that the star system was already lost. They could not hope to hold the Tyranids in space, for there were too few warships in the system to mount a workable counteroffensive. There was also no time to gather sufficient reinforcements to repel them. Informing the world's Planetary Governor of their findings, they prepared for the inevitable destruction of all life and consumption of the planet's biomass.At most, the best the Crimson Castellans could do, was lay their defences and attempt to hold back the Tyranid onslaught to evacuate as much of the population as time and resources allowed. Only seven hundred thousand out of a population of forty billion people could be saved. All Imperial servants of the higher orders were to be saved. The remainder were drawn from the women and children only, no exceptions.This was done by a random lottery, allowing everyone an equal chance, or else the planet's population would be killing one another before the xenos arrived. To compound matters, it was brought to the attention of Brother-Sergeant Yoth, the Commander of the Crimson Castle of Ector by local Adeptus Arbites authorities that there was possible xenos bioforms sightings in the deepest reaches of the underhive.Taking the threat seriously, Brother-Sergeant Yoth and Senior Enforcer Schreck were led into the dank depths of the underhive by a pair of failed Neophytes. Guiding the two Imperials into the tenebrous depths, they encountered a Lictor, a Tyranid scout bioform, which brutally slew the Enforcer and nearly killed Schreck. Fortunately for the humans, they received assistance from an unexpected arrival. A small cadre of Aeldari warriors slew the Lictor with their advanced Shuriken Weapons.The leader of the Aeldari introduced himself as Isarion the Dispossed, an agent of the Hand (Asurmen, the Hand of Asuryan, the so-called Phoenix King, and most powerful deity of the Aeldari pantheon). He explained that he had no quarrel with the humans, and the Aeldari were on the planet to help fight against their common foe. The Crimson Castellans were known to be highly xenophobic, and Brother-Sergeant Yoth was quite wary of trusting anything that the Aeldari had to say. After making his explanations, Isarion and his warriors disappeared as mysteriously as they had arrived.While the Crimson Castellans and the inhabitants of the world prepared their defences as best as they could, Astropath Prime Mazurn detected the presence of another Hive Fleet en route towards Ector, the leading edge of the splinter fleet of Hive Fleet Kraken that had arrived in the system through a dimensional rift. There was little time to redeploy the world's defence grid, for much of the planet's orbital weaponry had been moved to the sunward side of the planet, which was the expected approach vector of Hive Fleet Leviathan.Against the Kraken, coming from the other side of the world, Ector's depleted defensive stations and war satellites held but briefly before collapsing. The Kraken soon enveloped the world of Ector like a hand, as multiple tendrils encircled the globe. By this time, Brother-Sergeant Yoth reported the findings of his exploration of the underhive to Brother-Captain Raankin, explaining that they had encountered a Lictor, but the beast had been slain. He also informed the Space Marine Captain of his encounter with the Aeldari.Yoth vowed to hunt down the notoriously devious xenos and wring the truth of their true purpose from their scrawny necks himself. Informing Yoth of a second Hive Fleet that was rapidly approaching the planet, Raankin countermanded Yoth's desires and ordered him back to the surface. Now was the time when the Crimson Castellans would test their mettle against the Great Devourer.The scouring of the northern pole by the Tyranids took five solar hours. After this, there was no living thing larger than a snow hyrax above the planet's fiftieth parallel. The few human installation were overrun, the fires of their demise glittering upon the carapaces of a billion Tyranid creatures. With one purpose, the Great Devourer turned south. By the ninth evening of the battle, the forces of the Kraken came upon Hive Valentis, the Ice Spire, the most northerly of all Ector's city-peaks, and the smallest.The lottery for the refugees fleeing the doomed planet was over. Those not chosen to flee their homeworld were ready to fight, propaganda broadcasts booming out of city-wide Voxes constantly, extolling their duty to the Emperor and to instill devotion to their purpose. All would fight or else all would die. At the Fire Control Center of Valentis Hive, Brother Karsikon made ready the hive city's numerous artillery and heavy weaponry emplacements. When the chitinous horde of the Tyranid swarm made their rapid approach towards the hive city, Karsikon ordered the bombardment of the swarm.For two solar hours the guns rained a hellish barrage down upon the Tyranids. Ceasing fire after the third hour of the bombardment, Karsikon wished to see what it had accomplished. The first wave of bioforms had been utterly destroyed. But there would be others.Seven solar weeks passed and the Crimson Castellans' vigilance did not cease. After the first attack they had been expecting the Tyranids to mass immediately for a second, larger assault. From what Brother-Captain Raankin said, their tactics were unsubtle but brutal. Karsikon was disturbed by this. It was at this time that he discovered the reason for xenos' delay. Multiple contacts were detected approaching the Crimson Castellans' position. The enemy was now at elevation.This new wave of Tyranids was on the Space Marines and their allies in only minutes after their detection, streaking through the cold dawn of Ector. This Tyranid horde was composed of bioforms all outfitted with wings. Some were truly exceptional in size, Harridans with broods of Gargoyles clustered at their bellies. The Tyranids were testing their defences. This was the true attack. The Defence Lasers lit the swarm red, scores of searing energy beams striking lines of Tyranids burning from the sky. But the horde moved very fast, far faster than the terrestrial creatures that had composed the first onslaught.Tens of thousands were slaughtered, but the creatures did not falter. They closed the range quickly. Shortly after, the screams began as the hideous chittering swarm assailed the ramparts of Valentis. Informing Brother-Captain Raankin of the hive's dire status, before signing off, Karsakon communicated his intentions to die a glorious death. Grimly, Raankin wished Brother Karsakon to meet the Emperor with honour. Within only hours Hive City Valentis fell, and all the remaining hive cities of Ector fell to the Great Devourer only a few solar days later.With the help of Isarion and his Aeldari cadre, Chaplain Gorth, Brother-Sergeant Yoth and the two failed Neophytes, a handful of Crimson Castellans managed to make good their escape from the doomed world aboard a Thunderhawk gunship. The Aeldari soon disappeared (presumably through a Webway portal) as mysteriously as they had come.The Crimson Castellans also managed to evacuate the majority of their Chapter Serfs and human auxilia. But despite the Castellans' heroic efforts, the world of Ector had fallen to the Tyranids, another casualty in the seemingly endless war of Mankind against the Great Devourer.