Infestation of Drashin - High Cost of Victory: Several days after the Norn-Queen's death, the remainder of the Imperial Fists arrived from the Warp. Engaged in a war against the Orks of Antigon -- a campaign dubbed the "Crusade of Steel" -- they had responded immediately to Pugh's summons, but had found their fleet harried by Craftworld Aeldari vessels launched from Craftworld Saim-Hann.Faced with the choice of abandoning a portion of his strength to the raiders, or delaying his arrival at Drashin, the 2nd Company's Captain Helion had chosen to follow protocol and vanquish the immediate threat first. Had it not been for the interference of the Craftworld Aeldari, the Imperial Fists would have stood united at Drashin, and there was not a battle-brother in the newly-arrived fleet who did not blame the Aeldari for their Chapter Master's death.Unable to vent their wrath against those deemed most deserving of it, the Imperial Fists threw themselves into the purging of the surviving Tyranids from Drashin's surface, moving with such implacable vigour that little of the work was left for the hard-bitten veterans of the Catachan XXXI.Through it all, the Adeptus Mechanicus offered little assistance, although three Knights of House Krast did go against their orders and take the field at the Space Marines' side on several occasions.As the purging of Drashin continued, more sombre duties were performed. Vladimir Pugh's body was sent back to Phalanx so that his bones might be prepared as a relic for the ages to come.Some thought Darnath Lysander the perfect successor, considering that his previous errors had been washed away by his deeds since. Yet Lysander refused the honour, knowing that he had not yet learned the lessons of his recent past and could not take the Chapter Master's seat until he had done so.Instead, he reclaimed the captaincy of the 1st Company, which was now leaderless again following Acting Captain Julan's death at Pugh's side. The decision was therefore deferred until the business of Drashin could be concluded. However, Sergeant Garadon's rise to the captaincy of the 3rd Company was immediate.Pugh was not the only brother who fell to the Tyranids, but here the Imperial Fists had been fortunate. Rogal Dorn's legacy of blood and bone ensured that for every four warriors who had fallen, only one had perished. The others, coaxed back from oblivion's brink by the Apothecaries' skill, would yet live to serve their Chapter.Some would do so only with the aid of bionic implants. Others -- Captain Terrell amongst them -- would be forced by their injuries to take up other duties on Phalanx, rather than continue as active battle-brothers. Nevertheless, of some one hundred or so Space Marines who had fallen on Bleak Ridge or within the space hulk, near seventy would fight again.As the unbloodied companies spread out across Drashin in search of Tyranid infestation, Captain Garadon oversaw the investigation of the space hulk's half-sunken remains. Working in concert with the polar base's Enginseers, Techmarines dug their way through the vessel, looking for some clue as to what had brought the vessel to Drashin.At first, it was assumed that the Tyranids had merely infested the space hulk, but this was quickly discovered to be untrue. The site where Pugh had fallen was not an infested star vessel, but a mangled Hive Ship, concealed by the asteroids and spacecraft compacted around it.Clearly, the creatures had broken free during transit, and slaughtered the hulk's crew -- who, in a development too unlikely to be coincidence, bore the same glyphs as the Orks of the Magor Rift that Lysander had been fighting during the Crusade of Thunder. But who had captured the Tyranids in the first place, and why?The colouration of the beasts matched no configuration yet observed by Imperial forces, which was worrying enough. The hive fleet code-named "Behemoth" had more or less run its course some solar decades earlier, and the thought that there were other Tyranid fleets converging on the galaxy was a worrying one.After solar days of careful investigation, the searchers discovered the emaciated remains of a Navigator. He was imprisoned within the space hulk's drive units by a many-tendrilled cybercradle, and protected by a force field that withstood all attempts to breach it for more than a solar week. When the force field was finally dissolved, the Navigator died at once, killed by some suicide mechanism within the cradle.Further investigation of the Navigator's cybernetic interfaces revealed that Drashin had not been the space hulk's intended destination. The original course had been set for Terra, and it seemed likely that the Navigator had been able to resist his implants just enough to throw the vessel from its intended heading -- though bound body and mind, still he had found a way to serve his Emperor.Garadon was sure the defences around the Sol System would have prevented the space hulk doing to Terra what it had done to Drashin, but that did not diminish the plan's audacity.With the Navigator's death, it seemed that no one would ever know the architect of Drashin's woes. However, as the wreck of the space hulk was broken apart for salvage, a brass naming plaque was found emblazoned on the ancient Horus Heresy-era cruiser embedded at its heart. It read simply Hydros.The meaning of that name was lost on Garadon and his fellow captains, but not so on Lysander. It was a word he knew all too well. In the ancient legends upon which Warsmith Shon'tu had styled himself, Hydros had been the warlord's spear. When thrown, it had unleashed an all-consuming plague that devoured everything in its path.Lysander only knew of this because it had been one of the legends Shon'tu had recounted during the terrible days on the Iron Warriors' Fortress World of Malodrax, but he knew at once it was no coincidence. If the Tyranid swarm had taken full root on Drashin, or worse yet on Terra, a new hive fleet might have one day grown in the Imperium's very heart.Upon the Chapter's return to Phalanx, Lysander's fellow captains again made the attempt to have him take Vladimir Pugh's place. This time, Lysander gave the matter more careful consideration. The Imperial Fists needed leadership, that much was true, but some instinct gnawed at the First Captain's hearts.Unable to resolve the matter through conscious thought, Lysander spent many solar days silently meditating in the Cloister of Remembrance. On the fifth such day, Haldor Marzon, the Chapter's Chief Librarian and Pugh's closest confidant, intruded upon Lysander's gloom-laden solitude. There, the mystic explained that Pugh's order for the Crusade of Thunder to strike the Orks of the Magor Rift was not the censure that it had first seemed.During his long years of service, the Chapter Master had forged many allies throughout the Imperium -- and possibly beyond. Since Shon'tu's escape from the destruction of Malodrax, Pugh had used those connections to uncover any information he could concerning Shon'tu's plans.Though the Chapter Master had never succeeded in locating Shon'tu's base of operations, he had uncovered many of the Warsmith's allies, and set his Chapter to the business of their destruction. The strike in the Magor Rift, Marzon explained, had been the latest in a long line of similar actions.