Operation Hammerfall was the name given to the initial offensive that launched the Achilus Crusade to retake the Jericho Reach in the Segmentum Ultima in 777.M41. The operation was led by the Astartes of the Storm Wardens but included the forces of dozens of other Space Marine Chapters.
Indeed, of all the Space Marine Chapters of the Adeptus Astartes that contributed forces to the opening battles of the crusade, the Storm Wardens committed by far the largest single contingent.
By mutual assent of the crusade's ruling council and personal sanction of the crusade's designated leader Lord Militant Tiber Achilus himself, Ward-Master Lorgath Maclir, Chapter Master of the Storm Wardens, was appointed the figurehead and nominal leader of all of the Space Marine forces committed for the opening battles of the crusade.
The opening operation would achieve some of the most stunning victories, and suffer one of the most galling twists of fate, in the entire crusade.
Its initial strategic goal was the elimination of all T'au forces present in the Reach, an objective that was expected to be completed within a solar decade.
However, the Imperial forces discovered to their shock that the Human-settled worlds of the Reach, most of them former Imperial colonies, did not support the return of Imperial rule. These worlds' resistance slowed the crusade's momentum and dangerously stretched its lines of communication.
Despite an overwhelming victory led by Commander Maclir over the T'au at the world of Ravacene, the crusade's momentum was decisively halted when the forces of Chaos long present in the Reach since its Age of Shadow suddenly intervened.
A series of Chaos-directed assaults on worlds already held by the crusade ended the initial offensive of Operation Hammerfall and transformed the Achilus Crusade into a decades-long war of attrition eventually divided into three major salients.
Planning for Operation Hammerfall began in mid-773.M41, when Maclir was summoned to attend the Senatorum Imperialis on Terra. In sealed session, the High Lords of Terra bid the master of the Storm Wardens to lend their support to the man they had not an hour earlier confirmed as High Lord Militant of the Eastern Marches, Tiber Achilus.
Maclir would have fought alongside such a man regardless of the High Lords' wishes, but he knew that the undertaking at hand must be a truly epic one for the highest council in the Imperium to have summoned him in such a manner.
Then, the new Lord Militant emerged from the shadows below the High Lords' dais, and greeted his old friend. Achilus apprised Maclir of the flight of the Spear of Tarsus through the Jericho-Maw Warp Gate that had connected the Calixis Sector to the Jericho Reach at the other side of the galaxy, and of the weight of the discoveries made since.
Maclir committed his Chapter to the coming Achilus Crusade there and then, and the foundations of the operation were set down. While Achilus and Maclir laid their plans for the subjugation of the Jericho Reach, messengers were sent out to dozens of other Space Marine Chapters.
In many cases, Maclir sent his own brethren to petition his brother Chapter Masters to lend their support to the coming crusade. In other cases, Achilus dispatched his own agents and emissaries, so that in total, almost a hundred Space Marine Chapters were approached.
The requests for aid were by necessity short on details, for the need to conceal the existence of the Warp Gate was overriding. Some Chapters refused to commit based on the scant information they were given.
Others, notably those who had served alongside Maclir or Achilus in previous campaigns, agreed outright to lend whatever aid they were able, and within the year several dozen Chapters were committed to the Achilus Crusade.
A Space Marine command council was formed, consisting of the most senior officer of each Chapter represented in the force, and Maclir was elected its figurehead.
The build-up of military force and logistical support that precluded the crusade was an undertaking only the most brilliant of minds could have conceived. Achilus was a leader of prodigious will and vision, and the authority vested in him by the High Lords of Terra meant there were precious few limitations in the scope of his power.
Yet, the need to maintain secrecy remained paramount, for if the existence of the Warp Gate became known, the numerous enemies of the Imperium might utilise it to strike from one side of the galaxy to the other.
The totally unheralded arrival of Hive Fleet Behemoth on the Eastern Fringe had defied all strategic prognostications, and although most in the Imperium's highest echelons believed the threat overcome at the Battle of Macragge, others feared that another such foe might descend upon the region and, utilising the Warp Gate, strike directly towards the Imperium's heartlands.
Achilus conceived the plan of conducting the build-up in the guise of directing troops towards the Margin Crusade on the fringes of the Calixis Sector, for while that war still officially raged, in reality it had long ago lost momentum and become a fruitless meat-grinder.
Astra Militarum regiments were raised from the worlds of the Calixis Sector and numerous others. Strategic segmentum reserves, including veteran regiments originally drawn from such famed worlds as Cadia and Mordia, were committed to the crusade.
The Orders Militant of the Adepta Sororitas pledged the zeal of their Sisters of Battle. The Adeptus Mechanicus committed Titans, Knights, and Skitarii regiments. The Imperial Navy assembled the largest fleet deployed since the Battle of Macragge.
The Departmento Munitorum, by far the largest contingent in the entire crusade, mobilised countless support formations, without which not a single las-shot could have been fired or a single trench dug. Even the Rogue Traders answered the lord militant's call, and those he trusted were promised riches beyond even their wildest dreams when it came time to apportion the prizes of war.
But mightiest of all the contingents were the Space Marines of the Adeptus Astartes. Hundreds of Battle-Brothers were gathered under the banner of the Achilus Crusade, literally, for Maclir ordered a composite Crusader Company raised. Each Chapter present contributed Battle-Brothers to an elite honour guard whose sacred task was to wield and protect the Crusade Banner.
Finally, after several solar decades of planning, years of preparation and months of build up, the crusade was ready to embark. Incredibly, the undertaking had remained secret, the cyclopean bureaucracy of the Imperium ensuring, even without deliberate effort, that the flow of troops, materiel, and information was strictly one-way.
Though never openly acknowledged, it is suspected that the Inquisition had a hand in reinforcing the issue of operational secrecy, the little-known Ordo Redactor purging the archives of any data that might compromise security and tracking down and eliminating any who might let the secret out.
The Hammer Falls
Ten solar days before the Feast of the Emperor's Ascension in 777.M41, Lord Militant Achilus gave the final, irrevocable order, and the countdown to the crusade began. The first warriors through the Warp Gate were the Space Marine strike forces assigned to Operation Hammerfall, and these were led in person by Lorgath Maclir, who had planned every aspect of the assault in person, in minute detail.
The crusade's objective was to push the T'au out of the region and reclaim the worlds of the Jericho Reach for the Imperium of Man. It was Achilus' most cherished dream that the T'au would be so undermined by the crusade that they would fall back towards their own region of space and, in time, be destroyed utterly.
But for now, Achilus and Maclir held the T'au capital in the Reach, Tsua'Malor, firmly in their sights, and nothing, or so they thought, could possibly distract them from their goal.
Operation Hammerfall ranged ahead of the bulk of the crusade, smashing aside all enemy forces that dared stand before it. As hoped, the T'au were initially unprepared for the attack, coming as it did from an entirely unanticipated quarter.
The Space Marines fought as angels of death, conducting planet-strikes, boarding actions, and massive frontal assaults in the manner of the battles of the Great Crusade. Despite the potential for destruction, Maclir ordered that those worlds occupied by Human populations be spared unnecessary suffering and allowed to rise up against the T'au and join the crusaders.
Shockingly, the Human populations failed to welcome the crusade, let alone join it. Instead, their leaders declared the Imperium the enemy, rejecting all communications and asserting their independence.
As world after world rejected the crusade, the forces of Operation Hammerfall were forced to divert around planets they had no immediate resources to suppress. Initial planning had assumed that the worlds coreward of the Well of Night would be usable as staging points for later stages of the operation.
With the worlds rejecting the Imperium, the Space Marine strike fleets were forced to operate far from their rear echelons, and their lines of communication were becoming more stretched with every world they were forced to bypass.
Despite these setbacks, Operation Hammerfall achieved countless glorious victories, overwhelming the T'au in battle after battle. At Spite, twenty T'au battle cadres were utterly wiped out, while the Battle of Kaggeran sent an entire Air Caste picket fleet burning through the skies to crater several thousand square kilometres of the surface.
At Wrath, the T'au attempted to mount a rearguard action while they evacuated several hundred thousand of their worker caste. The Battle Barges of the Storm Wardens, Black Templars, and the Dark Sons Chapters annihilated them from orbit before seven entire Assault Companies made planetfall to destroy what little resistance remained.
Perhaps the greatest battle honour won in those opening months was that earned by Maclir himself, when he held the line at Epiphany Rock against a massive T'au counterattack. The xenos fielded heavy battlesuits, whose weapons were capable of punching straight through Adeptus Astartes Power Armour and which accounted for dozens of casualties before Maclir took the initiative.
The Storm Wardens Chapter Master led a teleport assault of the massed Terminator squads of a dozen Chapters, materialising in amongst the enemy formation and tearing it apart before the heavy battlesuits could re-deploy.
With Epiphany Rock smashed wide open, Maclir scented blood and drove Operation Hammerfall on still further, pushing the T'au back along the Hyades Ebb Warp route and down the length of the Arethusa Flux all the way to the Death World of Ravacene.
First Battle of Ravacene
There, amongst the ash forests and volcanic chains, the forces of Operation Hammerfall fought their largest and most costly battle to date. The T'au threw every asset they had into a last ditch effort to repel the Space Marine advance, committing Fire Warrior cadres, thousands of battlesuits, and massed grav tank wings.
Alien mercenaries not seen before or since swelled the T'au's numbers still further, and soon the ash coating the forest floor turned to a glutinous mire as the blood of xenos and Space Marine alike was spilled.
The First Battle of Ravacene raged for three solar weeks, neither side able to gain the initiative or strike a telling enough blow against the other. During the darkest days of the battle, it is said that Maclir was everywhere, bolstering the defence, leading bold counter-attacks, and taking the fight directly to the enemy without rest or respite. The Storm Wardens drew on every single one of their traditions.
Riding their mighty armoured Land Raiders and Predators in the manner their ancestors rode their huge Sacrisan steeds to war, the Storm Wardens smashed aside whatever T'au forces stood before them, dismounting to engage the enemy in the brutal melee of close combat and continuously testing themselves against the very best the T'au could field.
Maclir is said to have dreamed of seeing the white domes of the T'au capital in the distance, knowing that Operation Hammerfall was mere light years away from its objective and that one final push would see the crusade attain its primary goal. Achilus had always planned for a solar decade of war, yet Maclir sensed that victory could be won within mere months if one final push could be made.
Knowing that a second wave of Space Marine strike forces followed by a third of front line Astra Militarum regiments was fighting its way down the Hyades Ebb, Maclir ordered all available forces to mass at Ravacene and smash the T'au aside, so that the advance on Tsua'malor could begin without delay. Lord Militant Achilus signalled his assent and the final phase of Operation Hammerfall was ordered.
The Hand of Chaos
But Maclir's order was never enacted. All across the Jericho Reach, those worlds that had refused to yield to the crusade rose up, millions-strong armies and ramshackle fleets of ancient system defence vessels smashing into the crusade's exposed and over-stretched lines of communication.
Worse, it soon became apparent that the recalcitrant populations were not motivated by notions of mere misguided isolationism. Underlying the resistance was the hand of Chaos, the poison of the Ruinous Powers lending the armies strength at the very moment when the Imperium could have pressed home its assault and driven the T'au from the Jericho Reach.
Maclir's reinforcements never arrived at Ravacene. Instead, transport fleet after transport fleet was ambushed, encircled, and destroyed, entire regiments of the Astra Militarum perishing in the cold void before setting foot on a single world of the Jericho Reach.
Maclir raged in the face of such perfidy, swearing to avenge himself of the Traitors who had cost the Imperium its victory, for he saw there and then that Achilus had, if anything, been overly optimistic in his estimation that the conquest of the Jericho Reach would take a decade.
With Chaos raging in the central zones, Maclir knew the crusade might not complete its objective even in his own lifetime.
Ironically, it had not been even partially completed by the end of the lord militant's lifetime, for Achilus died in tragic, and some have said suspicious, circumstances when his flagship Proclamation of Wrath suffered a catastrophic Gellar Field collapse in 786.M41.
In truth, the longstanding friendship between Achilus and Maclir had soured by the time of the lord militant's death, both warriors deeply embittered by the crusade's descent into a gruelling war of never-ending attrition.
- Deathwatch: Honour the Chapter (RPG), pp. 18-22