Luna Wolves (Sons of Horus)

"I thought the Luna Wolves were supposed to be the most aggressive of us all. That's how you like the other Legions to think of you, isn't it? The most feared of Mankind's warrior classes?" - "Our reputation speaks for itself, sir."

- First Captain Sigismund of the Imperial Fists Legion and Captain Garviel Loken of the Luna Wolves

The Luna Wolves were the XVI Space Marine Legion raised by the Emperor of Mankind on Terra at the dawn of the Great Crusade in the late 30th Millennium. After the Emperor discovered the Legion's Primarch Horus on the world of Cthonia, and gave him command of the Luna Wolves, Horus went on to lead the XVI Legion in earning thousands of battle honours over the span of the 200 standard years of the Great Crusade. Few other Legions could match their achievements and of those that could few could rival the XVI Legion for the brightness with which their victories shone. Spread across hundreds of Expeditionary Fleets and on countless battlefields, the Luna Wolves broke the enemies of the Imperium and pushed the Great Crusade forwards. The position of Horus as the Emperor's favoured son undoubtedly enhanced their triumphs. The Emperor fought alongside all of the Primarchs, and led all of the Legions at different times, but Horus and the Luna Wolves stood beside him for many of his greatest victories. The Luna Wolves stood with the Emperor from the beginning of the Great Crusade until the Emperor's return to Terra following the triumph of the Ullanor Crusade and the elevation of Horus to the esteemed rank of Warmaster and commander-in-chief of all the Emperor's vast armies. yet the character of any Legion was an echo of their Primarch, one can see the flaws of the father in the pride of his sons. Brutal, ruthless and unwavering but also honourable, and once loyal beyond question, the history of the Luna Wolves is the history of the ambition of the Imperium itself, and the flaws that broke its founder's dreams of unification and glory for all Mankind asunder.

The XVI Legion was originally known as the Luna Wolves during the Great Crusade. In honour of Horus' great achievements during the latter years of that era after the Imperial victory over the Orks during the Ullanor Crusade, the Emperor suggested that the Legion be renamed the "Sons of Horus" to honour his most beloved son's accomplishments. Horus at first refused, fearing that to so set himself above his Primarch brothers would lead to factional strife, but he eventually instituted this change following his conversion to the service of the Dark Gods of Chaos on the world of Davin. After Horus' treachery and final defeat at the Battle of Terra during the Horus Heresy, however, the XVI Legion was renamed the "Black Legion" by its new Warmaster, Abaddon the Despoiler, the former First Captain of the Legion and commander of its elite 1st Company. The new name was chosen after the Astartes of the Sons of Horus painted their Power Armour black in grief at the death of their Primarch and shame at their failure to overthrow the False Emperor and seize control of the galaxy in the name of the Ruinous Powers.

The Wolves of Terra
In the time when the Emperor's eye first began to fall beyond Terra, he raised new armies to fight his Great Crusade. He drew these new troops in part from the forces that had already unified Terra during the Unification Wars of the late 30th Millennium, from willing Terran volunteers like those who comprised the XVI Space Marine Legion who were implanted with the gene-seed of their missing Primarch Horus like all the Astartes of the First Founding. These recruits were also drawn in part from the Emperor's subjugated enemies, and together they represented the first generation of Space Marines. Like most of the embryonic Space Marine Legions, the XVI Legion drew all of its first recruits from the Terran population. Though it is difficult to be certain based on the existing Imperial records from this lost time, there are indications that many of the XVI Legion’s early intake came from the hunter clans of the Jutigran Bowl and the Samsatian sub-plate slums. Perpetual conflict and the harshness of life on the desolate margins of Terran society had given these people the hard edge of ruthlessness and independence that would serve a Space Marine well.

The XVI Legion made war with abrasive aggression. Perhaps through the influence of their genetic heritage or the use the Emperor put them to, the Space Marines of the XVI Legion became synonymous with sudden and overwhelming shock assaults. To the XVI Legion fell the swift prosecution of battle and the bloody termination of campaigns. Their attacks were preemptive as often as they were part of an existing conflict, their forces either the first deadly threat unleashed by the Imperium or preserved to enact a final, killing blow. The First Pacification of Luna was perhaps the most famous of these early victories for the XVI Legion, but the breaking of the Coriolis Enclaves and the Five Winter left scars in the collective consciousness of Terran society that persist even now. In the Capridian Sinks, it is still common for traders and gamblers to refer to the Legion’s ancient number of sixteen as "the counting of the wolf."

It is said that the Astartes of the XVI Legion were unleashed to begin and end wars their enemies did not know they were even fighting. They would come out of the night or in the dawn, carried in the holds of Stormbirds and Storm Eagles, flanked by squadrons of escorting Lightning Crows. Those who witnessed such attacks say that the XVI Legion were fighting eye-to-eye with the enemy before the thunder of their first volley of missiles and shell-strikes had faded. The warriors who fought these battles were of a character wholly in keeping with their reputation. Proud, little given to humour or empathy, nor to mysticism or even the ritual of the military elite, they were a breed apart from the true human forces that had fought at their side. Their aggression was clear in their every action, but so was the strength of the control that held it in check, and the needs of that ancient age easily accommodated such a belligerent and cantankerous attitude.

At some time the notion of the Emperor sending his "wolves" to break intractable or potential enemies took root in the consciousness of the new-born Imperium, with the Pacification of Luna its apocryphal source. The XVI Legion embraced the epithet "Luna Wolves" with relish. The wolf's head became a common icon among them, the link being somewhat abstract, wolves themselves having been largely relegated to existence as gene-stock for bio-weapon beasts on Terra itself, and synonymous with controlled savagery. The wearing of pelts of such augmented canid predators increasingly marked field commanders and Legion officers. The XVI would not be the only Legion to bear such a title and embrace this imagery as their own, but they were the first.

Cthonia
The Luna Wolves were the first Space Marine Legion to begin recruiting from another world beyond Terra. In this case, the new pool of Aspirants was found amongst the adolescent human males drawn from the violent hive city gangs inhabiting an ancient Mining World called Cthonia. Cthonia was located in one of Terra's closest neighbouring star systems in the Segmentum Solar and was within reach of spacecraft that could travel at only sublight velocities before the invention of the Warp-Drive. As a result, Cthonia had been colonised, built upon, tunnelled and mined since the dawn of human interstellar space travel millennia before the beginning of the Dark Age of Technology. Due to this unusually long period of exploitation by Mankind, all of the world's natural resources had been stripped away and used up centuries before, and the ancient mining technology had long since been rediscovered and removed by the Tech-adepts of Mars. The planet that remained was largely useless and abandoned, completely riddled with catacombs, crumbling industrial plant and exhausted mine-workings.

Horus Lupercal
Horus, the true Primarch of the Luna Wolves, was the first of the Primarchs to be recovered by the Emperor, having been cast in his gestation capsule through the Warp much closer to Terra than the others by the Ruinous Powers, and he was found at a much younger age. Whereas the early history of many Primarchs is extensively if unevenly documented, the same cannot be said of Horus. Contradiction and omission tarnishes all accounts of Horus' formative years. It is clear that the Emperor did find Horus and also that he took command of the XIV Legion early in the Great Crusade. Beyond these manifest facts agreement between sources is decidedly lacking, some even placing Horus on Cthonia as a foundling. Like many of his brethren, these sources say that the young Primarch thrived in Cthonia's harsh environment, learning his first lessons in war and killing from Cthonia's tech-barbarian kill-gangs. Another source claims that Horus returned to Terra itself. It is said that Horus grew at the Emperor's side, learning from his father even as they took back the Sol System and forged the alliances between techno-barbarian nations and with the Mechanicus of Mars that created the Imperium of Man. Other highly creditable claims state that the Emperor found Horus, the first of his lost sons, but neither source specifies where, or the location of this finding. Surrounded in millennia of myths and allegory, the truth of Horus' origins will more than likely never be known. As a result, Horus was for many standard years the Emperor's only son, and there was a great affinity between them. The Emperor spent much time with his protege, teaching and encouraging him. Horus was soon placed in command of the XVI Legion, which he renamed the Luna Wolves -- 10,000 Astartes created from his own genetic code. With these superhuman warriors to lead, Horus accompanied the Emperor for the first thirty years of the Great Crusade that had begun in ca. 800.M30, and together they forged the initial expansion of the young Imperium of Man.

A Human Harvest
By the time the Great Crusade began in circa 800.M30, Cthonia's mines were long spent, but it had a resource that the new Imperium needed more than metals and jewels: hardened fighters and born survivors in their millions; a lean and hungry race of killers with no illusions about the horrors of the universe. Cthonia, relatively close to Terra in the void, and with whom some minor intermittent contact had been maintained even through the Age of Strife, had its murderous and strife-torn population marked by one of the first Expeditionary Fleets to leave the Sol System. To fuel the growth of the early Space Marine Legions, the Imperium took full advantage of the bounty that Cthonia provided. At the time of the First Founding, Cthonia helped provide the necessary flesh for the gene-wrights of Luna to fuel the growth of the Legiones Astartes. One report talks of so-called Imperial "recruitment squads" harvesting tens of thousands of Cthonian gangers and shipping them away, chained together in the holds of prison-shuttles, to the geno-laboratories of Luna. The majority were impressed troopers for the Crusade's Imperial Army regiment, but the finest specimens were taken for induction into the XVI Legion, later named the Luna Wolves when Horus took command of it. On Luna these chosen sons of Cthonia were reborn as the superhuman Astartes of the XVI Legion. It was more common for the first Space Marine Aspirants to be volunteers from Terra, and later, after the rediscovery of the Primarchs, from Feral or Feudal Worlds, however after the usual hypno-psychological indoctrination process, the Luna Wolves created from the men of Cthonia emerged as excellent and ferociously powerful Space Marines.

A Legion Reborn
With the induction of the genestock from Cthonia, the XIV Legion was remade, perhaps even without conscious thought. For the Terran Space Marines, their new brothers brought with them their own customs, attitudes and modes of thought, and ingrained inheritances of a thousand generations of callous violence and the ruthless pursuit of survival that the indoctrination practices of the time could modify and perhaps suppress but not erase, and after all, perhaps that was the point. As the Terrans fell in battle their voices and the more ordered military traditions they had been trained in became fewer and fainter. The marks of change were many and subtle, not overwriting entirely but bringing unique character to what had gone before. Examples of this change came slowly. Topknots and mohawks as sported by the Cthonian gang head-hunters became common throughout the ranks as armour and personal decoration. Blooding in battle to honour a worthy foe was marked often by a scratch across a helm's eye socket. Perhaps most tellingly, the Cthonian word for cutting the throat of an enemy gang-killer in a single combat "Aebathan" became a common term in the ranks to describe the completion of a campaign, and the personal charisma and reputation became a feature commanders, as if the ways of the Cthonian gang lords stained their understanding of leadership, and this applied none more so than their Primarch Horus whose cult of personality was universal within the Legion.

The character of the Luna Wolves in battle did not change, if anything it seemed to have become stronger over time. The Legion strove to maintain the flexibility to allow them to fight any war or enemy they might encounter on their own terms, but where possible the application of sudden and overwhelming force was their favoured form of attack, and that of their Primarch. As a doctrine this became bound up with a savage ferocity born of Cthonian blood, and wielded with ferocious intelligence and the matchless tactical instinct of their Primarch. Star system would often fall to the Legion in a single engagement: warships would cut in from the system's edge, forming a spear formation that would break into many smaller blade tips to strike at planets, moons and space stations. Orbital bombardment and simultaneous mass orbital drops would break the enemy's strength and will to resist. Tactical threats were systematically identified, isolated, outflanked, encircled and destroyed with merciless precision and close-quarter savagery which spoke of apex pack predators splitting a herd and gutting its members with lightning fury. The Imperial armies that followed in the Luna Wolves' wake often had little to do but scrape suddenly compliant worlds clean of the leavings of battle.

Sons of Victory
The Luna Wolves' approach to the Crusade was direct and brutal, and their results were often inelegant if unmistakably effective. Though it was bloody the Legion's progress was undoubtedly swift and laurels of victory were heaped upon the Luna Wolves and above all their Primarch Horus. Time and again, the Luna Wolves would break resistance on a world and move on to the next campaign with barely a backward glance. In this method of conquest the character of the Luna Wolves' tenacity and ruthlessness was displayed during the conquest of the Sol System, as well as their savage mentality and ferocity of the gang-wars of Cthonia where prisoners were simply unwanted mouths to feed. War was a matter of identifying the strength and leadership of the enemy, isolating it and then obliterating it. In the same way that a gang leader's eyes would find a rival and their knife would follow, so the Luna Wolves conquered. Brutal it might have been but to the Space Marines of the Luna Wolves it was a matter of necessity; wars could be brutal and short or long and wasteful. Driven by the energy of the Great Crusade their method fitted the needs of the age.

The Luna Wolves waged war for 200 years, pushing back the darkness with fire and blood. Their victories were manifold and Horus' generalship was legend, and so it was that the respect of their brother Legions rose to almost unrivalled heights. In tens of thousands of battles they were rarely defeated. In every mode of deployment they excelled, whether as the spearhead of a star cluster-sized assault or an individual squad supporting a grand formation of the Imperial Army. Other Legions, sometimes hostile to the interference of their brother Legions, would request campaign placement amongst the Luna Wolves and welcome it in return.

Much of the Luna Wolves' reputation was the reflection of the qualities of their Primarch. Horus' charisma and unequalled record lent him a measure of respect unrivalled among his brother Primarchs, while Horus himself demonstrated an almost preternatural talent for wielding the relative strengths of the other Legions to their best advantage on a strategic level. Horus was said by some to be without peer beneath the Emperor. Certainly he was rare amongst the Primarchs in that he commanded the respect and the loyalty of all, and backed it up with strategic and tactical genius. Others commanded larger Legions, saw more deeply, excelled beyond Horus in certain crafts of warfare and lore, or perhaps drew greater fraternal affection, but only Horus could hold every view and ideal in his mind. Even the most difficult of Primarchs are known to have deferred to Horus in many matters.

Triumph of Ullanor
"You are like a son and together we have all but conquered the galaxy. Now the time has come for me to retire to Terra. My work as a soldier is done and now passes to you for I have great tasks to perform in my earthly sanctum. I name you Warmaster and from this day forth all of my armies and generals shall take orders from you as if the words cam from mine own mouth. But words of caution I have for you for your brother Primarchs are strong of will, of though and of action. Do not seek to change them, but use their particular strengths well. You have much work to do for there are still many words to liberate, many peoples to rescue. My trust is with you. Hail Horus! Hail the Warmaster!"

- The Emperor of Mankind, the Triumph of Ullanor

Though the Luna Wolves had won many victories in their years of ceaseless conflict, one would eclipse all others and see them reborn once again. The greatest of the nascent Imperium's victories during the high point of the Great Crusade came in the form of the defeat of the largest Ork empire ever encountered. The Ullanor Crusade was a vast Imperial assault on the Ork empire of the Overlord Urrlak Urruk. The capital world of this Greenskin empire, and the site of the final assault by the Space Marine Legions, lay in the central Ullanor System of the galaxy's Ullanor Sector. The Crusade included the deployment of 100,000 Space Marines, 8,000,000 Imperial Army troops, and thousands of Imperial starships and their support personnel. The Ullanor Crusade marked the high point of the Great Crusade's vast effort to reunite the scattered colony worlds of humanity. The Orks of Ullanor represented the largest concentration of Greenskins ever defeated by the military forces of the Imperium of Man before the Third War for Armageddon began during the late 41st Millennium. Following the defeat of the Orks of Ullanor, the Emperor of Mankind returned to Terra to begin work on his vast project to open up the Eldar Webway for Mankind's use. In his place to command the vast forces of the Great Crusade he left Horus. In the aftermath of this Ullanor Crusade, Horus was granted the newly-created title of “Warmaster”, the commander-in-chief of all the Emperor’s armies who possessed command authority over all of the other Primarchs and every Expeditionary Fleet of the Great Crusade. Before returning to Terra to oversee the next phase of the creation of his stellar empire, the Emperor suggested to Horus that he rename the XVI Legion the "Sons of Horus," in honour of their Primarch and to show his preeminent place amongst the other Primarchs. Horus initially declined this honour, not wishing to be set above his brothers, and so his Legion continued as the Luna Wolves for a little while longer. But Horus and the other Primarchs never came to terms with the Emperor's absence. Their hurt feelings over his seeming abandonment of the Great Crusade to pursue a secret project whose purpose he chose not to reveal to his sons laid the seeds of jealousy and resentment that would ultimately blossom into the corruption that begat the Horus Heresy.

Notable Campaigns

 * First Pacification of Luna (Unknown Date.M30) - This early Imperial campaign was the first operation mounted by elements of the Legiones Astartes beyond the skies of Terra. The Wars of Unity were still raging across the surface of Mankind's birth world. Luna was the bastion of a conglomeration of resurrectionist gene-cults, the members of these cults believing that human nature was both fractal, fractured and transcendent. Each of these Selenar Luna gene-cults clung to a different set of archetypes. Each of these cult members was a product of creation by the gene-wrights according to the formulae born in the Dark Age of Technology. Resurrected in body time and time again they attempted to reach a true personification of a single archetype. In their subterranean complexes the cults were powerful, insular and resistant to the Imperial Truth. The Imperials would have normally dealt with the insular cults in the usual matter - by obliteration. The fact that the gene-cults had something that the growing Imperium needed complicated that position. The Selenar returned the Imperial entreaties with silence. As the threats began to outnumber the offers the Luna cults began to gird themselves for war. So it was that the Emperor ordered Luna to be pacified, their beliefs broken and their craft yoked to the needs of the Imperium. To this task the Emperor set three of his Legions most suited to his purpose on what some Imperial chroniclers name as the first true battle of the Great Crusade, the combined force of the VII, XIII (Imperial Fists & Ultramarines) and XIV Legions lifting from the surface of Terra in a scattering of rocket flame. The as yet unnamed XIV Legion had been chosen for the force's vanguard, operating in full strength. Cutting their power to their assault craft, they drifting silently towards Luna like arrows fired into the night. As the smaller wave of the VII and XIII approached the weapon system embedded in Luna's surface lashed the oncoming force. The XIV assault craft, unlooked for and unseen, struck their targets like a dagger in the night. Within six hours of the first shot being fired Luna was pacified. Faced with annihilation the surviving Selenar bent the knee instead, their surrender communique calling for the Emperor to "call off his wolves." Broken and humbled the enslaved gene-wrights of Luna would help forge the next generation of Legiones Astartes and fuel the conquest of the stars.
 * The Gorro Hollowing (Unknown Date.M30) - Within the Telon Reach was an Ork empire that rivalled that centred on Ullanor, and at its heart was the scarp sphere of Gorro. The Ork tech-caste dominated the Orks of Gorro and had made the world their own. The dominant tech-caste on Gorro seemed to be fascinated by a form of plasma technology never encountered before or since. Capable of a destructive yields of terrifying potency these plasma weapons had done much to blunt the Crusade's advance across the Telon Reach. The Emperor decreed that Gorro must be destroyed. When a thousand strong fleet dropped out of the Warp above Gorro it was the Emperor himself who gave the order to begin the assault. Horus, ever the dutiful and favoured son, stood at the Emperor's side and watched as tens of thousands of assault craft spread out from the fleet. The Luna Wolves teleported into the scrap layers beneath the planet's surface, forced to hollow out Gorro from within due to the planet's high resistance to orbital bombardment. In the vanguard was the Emperor and by his side was Horus and a guard of black armoured Justaerin Terminators and golden-clad Legiones Custodes. As they attacked, the Ork resistance they faced was near overwhelming. The Orks of Gorro were huge and augmented with scrap bionics. Some stood taller than dreadnoughts and their weaponry burned through power armour easily. At the height of the battle the fury of the Orks split the Emperor from his guards. Alone he slew hundreds of them until a blast from an Ork plasma weapon opened his guard and one of the Ork leaders seized him. The creature's strength was so great that it took hold of the Emperor and buckled his armour. As the creature's grasp closed to throttle the Emperor, Horus stormed through the press of battle and cut the Ork's arms from its body with a single blow. Together father and son led their forces deeper into the sphere until they reached the centre of Gorro. The Emperor worked to collapse the self-sustaining plasma sphere that contain a warp-fold envelope, so that Gorro would implode into the Warp. Without its power source the scrap world collapsed in on itself. A hollow skin of rusted metal around an empty void was all that remained to mark the death of the Ork world.
 * Castigation of Terentius (Unknown.M30) - When the Great Crusade entered the Ordoni Cluster they encountered the formidable warlord Vatale Gerron Terentius. Observing the forces arrayed against him, Terentius was forced to take the path of survival and surrendered. The Imperium had need of such men like Terentius, and the Great Crusade gave him opportunities and riches such as he had never dreamed. Given a small fleet of ships and a handful of Imperial Army regiments Terentius grew his forces by conquest. For five decades he rose in power and reputation, conquering worlds around the Halo Stars. At the height of his powers he had the ear of the Sigillite and the countenance of several Primarchs. When he turned against the Imperium many were shocked. Terentius began to conquer already compliant planets, his contra-crusade conquering system after system. Soon he had fleets of ships, tens of millions of soldiers and the loyalty of a hundred worlds. Ringed by fortress worlds this rebel empire began to eat up Imperial worlds around the Halo Stars. The Imperium responded by sending Horus and his Luna Wolves Legion to not only breaking the renegade but to demonstrate to any others the inevitability of a betrayer's defeat. Horus elected to not only use his Legion to complete the task at hand and sent personal requests to his brothers which saw substantial strength from the Night Lords, Iron Hands, Alpha Legion joined to the might of the Luna Wolves. Soon rebel forces were fragmented, driven by tales of culled worlds. It is said that it was at the moment that Terentius realised he could not win that the Luna Wolves came for him. As they dropped from the Warp within weapons range of Terentius' ships they annihilated half of his command fleet. Horus himself teleported onto the bridge of Terentius' flagship along with 50 of the Justaerin and slaughtered all they found there. Terentius died unrepentant as he was slain upon Horus' talon. With Terentius dead his rebellion crumbled, the castigation continued. Horus, his pride slighted, is said to have ordered the Night Lords to decimate every world within Terentius' rebel empire. Added to this the power of the Iron Hands and elements of the Ordo Reductor were brought to bear on every structure on Terentius' bastion worlds. So his realm was slaughtered, his cities smashed to dust, and his world's very air laced with toxins. The castigation complete Horus sent the gold-dipped skull of Terentius to Terra with the warning carried on the lips of the messenger that bore it, "So perish all traitors."
 * Fall of Reillis (Unknown Date.M30) - During the first thirty years of the Great Crusade, at the fortified city of Reillis, a human settlement unwilling to accept Imperial Compliance, the defenders used secret tunnels to infiltrate behind the besieging Imperial army and hundreds of enemy shock troops swamped the Imperial command encampment. Unprepared and unarmoured, the Emperor and Horus fought back-to-back until a plasma blast stunned Horus and sent him staggering to the ground. The Emperor stood over the fallen Primarch and refused to give ground until reinforcements arrived to drive their attackers back. The Emperor had returned the favour of his son saving his life on the Ork world of Gorro. This incident helped to forge an unusually close bond between the Emperor and his gene-son, closer than that between any of the other Primarchs and their father.
 * Keylek Genocide (923.M30) - Early in the Great Crusade the Luna Wolves fought against the hostile alien reptilian race known as the Keylekid on the world of Keylek, ultimately wiping these reptilian xenos from the face of the galaxy. This was a long, brutal and miserable genocidal campaign that was fought long before Horus was made the Imperial Warmaster. At this time Horus was referred to simply as "The Commander" by the Astartes of his Legion.
 * Compliance of Davin (Unknown Date.M30) - The Feral World of Davin, codified as Sixty-Three Eight (63-8), was the eighth world brought into Imperial Compliance by the XVI Legion's 63rd Expeditionary Fleet some 60 standard years before the start of the Horus Heresy. The indigenous feral warriors of this world briefly attempted to resist being conquered by the Imperium, but were forced to surrender as they were overwhelmingly outmatched militarily by the Astartes. The warrior tribes were allowed to remain mostly intact as they had impressed Horus with their courage on the battlefield and their willingness to learn to adapt to Imperial culture. The military campaign was brief, and the Luna Wolves departed after the surrender of the Davinites, taking with them their concept of the warrior-lodge, which were quickly adopted throughout the Luna Wolves fleet. A detachment of the XVII Legion, the Word Bearers (then known as the Imperial Heralds), under the command of First Captain Kor Phaeron was left to shepherd the people of Davin into the light of the Imperial Truth. The Imperial governorship of the planet was give to Commander Eugen Temba of the Imperial Army, a close friend and confidante of Horus. Long after the 63rd Expeditionary Fleet departed the star system, the new Planetary Governor soon found that the inhabitants of Davin's moon refused to comply with Imperial rule. This would eventually result in Governor Temba and his Imperial garrison force being struck down by a sorcerous attack unleashed by Davinite shamans of Chaos on Davin's moon, an attack that would twist their perceptions away from their oaths of fealty to the Imperium, succumbing to the corrupting influence of the Plague God, Nurgle. Unknown to the Imperials, the entire population of Davin had long been servants of the Dark Gods of the Warp. The corruption of Temba and his Imperial Army garrison forces would ultimately necessitate the return of the Luna Wolves Legion 60 years later, and lead to the eventual corruption of Horus.
 * Compliance of Darrowmar (Unknown Date.M30) - The Luna Wolves fought alongside the Night Lords Legion in bringing the world of Darrowmar into Imperial Compliance.
 * Compliance of Tethonus (Unknown Date.M30) - The Luna Wolves fought against an unidentified xenos-adversary whose identity is not recorded in existing Imperial records while bringing the world of Tethonus into Imperial Compliance. This Compliance action was a long siege of the xenos fortress-states on Tethonus. Horus had tasked the masters of the Forge World of Diamat to create continental siege machines; vast artillery pieces that could devastate the most powerful fortifications. But the war machines took much longer for the forge masters to complete than planned. By the time they were finished, the campaign on Tehonus had been over for over a standard year and a half, and Horus had moved on to other conquests. So the weapons were put into a depot on Diamat against the day when he would come to claim them. Fifty standard years later, Horus would reveal his perfidy at Istvaan III, and would send raiding forces to claim these siege engines for later use in his attempt to overthrow the Emperor of Mankind.
 * Assault on Dahinta (Unknown Date.M30) - On the world of Dahinta, the Luna Wolves fought against a race of self-aware machines called the Overseers, who were led by the artificial intelligence known as the Archdroid. One of the Emperor's longest-standing commands was that no sentient machines could be allowed to exist, for they had nearly caused the extinction of Mankind when they had rebelled against their human overseers during the Dark Age of Technology. Despite heavy casualties amongst, the thinking machines were wiped from the face of Dahinta by the savagery of the Astartes. Only after the campaign had ended was the full truth learned: the Overseers had been created by a vanished offshoot of humanity that had settled Dahinta, perhaps during the Age of Technology. The Overseers had cared for their lost masters' crumbling cities long after they had become extinct or left their homeworld behind.
 * Pacification of Schravaan (Unknown Date.M31) - This was a joint Imperial Compliance conducted by the Luna Wolves, Iron Warriors, Imperial Fists, and the Emperor's Children Legions against the xenos Badoon on the world of Schravaan. The Iron Warriors won a great victory when they stormed the final refuge of the Badoon. They breached the defences and held while the other Legions carried the city beyond. During the following victory feast, Horus proclaimed Perturabo the greatest master of siege warfare in the Great Crusade. Fulgrim, the Primarch of the Emperor's Children then inquired to his brother Dorn whether he thought even the defences of the Imperial Palace could resist the Iron Warriors, in which Dorn replied that he regarded the defences as being proof against any assault if well-planned. Perturabo flew into a rage and unleashed unfounded accusations against his brother. After this the two rarely spoke, and neither Legion would serve again in the same campaign for the remainder of the Great Crusade.
 * Compliance of Krypt (Unknown Date.M31) - The Compliance of Krypt was a relatively short campaign conducted during the Great Crusade by both the Luna Wolves and the Death Guard Legions against the Orks upon the frozen plains of the world of Krypt. Fighting together for more than a week across the frozen surface of the planet, the Space Marine Legions turned the blue ice dark with xenos blood. The Luna Wolves’ Captain Garviel Loken and his 10th Company are known to have fought alongside Death Guard Battle-Captain Nathaniel Garro and his 7th Great Company at this time.
 * Tyrade System Compliance (Unknown Date.M31) - The Luna Wolves served alongside a detachment of the V Legion, the White Scars, during the Imperial Compliance of the Tyrade System. This action occurred seven years before the Battle of Istvaan III and the start of the Horus Heresy.
 * Ullanor Crusade (Unknown Date.M31) - The Ullanor Crusade was a vast Imperial assault on the Ork empire of the Overlord Urrlak Urruk during the Great Crusade of the early 31st Millennium. The capital world of this empire, and the site of the final assault, lay in the Ullanor System of the Ullanor Sector, which had long been under the dominion of Urrlak Urruk's Greenskin pocket empire. The Crusade included the deployment of 100,000 Space Marines, 8,000,000 Imperial Army troops, and thousands of Imperial starships and their support personnel. The Luna Wolves spearheaded the assault into the heart of Urlakk's fortress-palace. During the height of the assault, Horus and a retinue of Luna Wolves Terminators from the elite 1st Company came face to face with the massive Ork Warlord and a retinue of 40 Ork Nobs. Horus charged into the Nobs, hacking them apart with his Lightning Claws until he finally faced the Ork Overlord himself. Urlakk was simply no match for the Primarch's skill and unnatural power. First crippling his enemy, Horus hefted Urlakk`s broken body out onto the roof of the Greenskin's palace and threw it screaming from the battlements to fall far below amongst the horde of Orks still assaulting the lower levels. Seeing their leader defeated sent a panic through the Greenskin forces, which started to fall back from the Terminators. But the fleeing mobs found they had nowhere to run, as the outer walls had been breached by the attacking Luna Wolves, and the day turned into a slaughter. In the Overlord's chamber, Horus found every Ork and Terminator dead, apart from the gore-drenched First Captain of the 1st Company, Ezekyle Abaddon, who was surrounded by crushed and Ork bodies. The Ullanor Crusade marked the high point of the Great Crusade's vast effort to reunite the scattered colony worlds of humanity. The Orks of Ullanor represented the largest concentration of Orks ever defeated by the military forces of the Imperium of Man before the Third War for Armageddon began during the late 41st Millennium. Following the defeat of the Orks of Ullanor, the Emperor of Mankind returned to Terra to begin work on his vast project to open up the Eldar Webway for Mankind's use. In his place to command the vast forces of the Great Crusade he left Horus. Horus was raised to the rank of Imperial Warmaster and given command authority over all of his fellow Primarchs and every Expeditionary Fleet of the Great Crusade. But the Primarchs never came to terms with the Emperor's absence. Their hurt feelings over his seeming abandonment of the Great Crusade to pursue a secret project whose purpose he chose not to reveal to his sons laid the seeds of corruption that would ultimately blossom into the Horus Heresy. Yet the Emperor sent word from Terra that in honour of the great victory at Ullanor, the Luna Wolves should henceforth be known as the Sons of Horus, in honour of their Primarch's singular deeds, though Horus, with typical humility, chose not to rename his Legion at this time.
 * Compliance of Melchior (Unknown Date.M31) – The Imperial Compliance of Melchior was a joint campaign that was carried out by both the XVI Legion and the Blood Angels Legion. The world was the last bastion of the xenos known as the Nephilim -- hulking entities of roughly humanoid shape who were smooth like carvings of soapstone, with abstract shapes approximating arms and legs. Their dome heads emerged from their shoulders without a neck, and an array of olfactory slits and eye-spots ringed the surface of their skulls. In the light, the Nephilim looked like objects crafted of blown glass, their semi-transparent flesh glowing in the bright day. The Nephilim possessed an unhurried, careful agility like that of sea-going creatures seen through the walls of a glass tank. They moved deceptively slowly through air as if they were swimming in water, but they could move fast if they wished, darting and spinning, becoming difficult to hit. The alien giants, mocking humanity’s great dream of peace and unity, had left a trail of destruction behind them that had claimed a hundred worlds before they had come to rest upon Melchior. Sagan, the DeCora Spine, Orpheo Minoris, Beta Rigel II; each of these planets had been denuded of all human life, populations herded into empath-chapels as big as mountains and then slowly consumed. Even their name, Nephilim, the name of the fallen seraphs, was a name taken from ancient human mythology -- that of Terra, Caliban and Barac. The true horror of it was that the Nephilim used those they preyed upon to do their soldiering for them, snaring the pliant, the lonely, the sorrowful with their ideal of an attainable godhood. They plied their victims with stories of eternal existence for the faithful, of endless sorrow for the agnostic; and they were very good at it. Perhaps the xenos really believed that what they were doing was somehow taking their victims closer to a form beyond flesh, to an afterlife in an eternal heaven-state; it did not matter. With their advanced technology they implanted bits of themselves into their thralls to further their communion. They cut their own flesh and made living masks to mark their devotees. The Nephilim controlled minds, either through the transmitted power of their will or through the weak character of those they chose. They were an affront to the Emperor’s hope for the creation of the rationalist, secular galaxy outlined by the Imperial Truth. They represented not only an offence to the purity of a precious human ideal but in their insidious cuckoo-nest displacement of those who foolishly gave them fealty. For what the aliens fed upon, what the Scout Marines of the Blood Angels and Luna Wolves had seen and reported back, were the very lives of those who cherished them. The empty chapels were piled high with stacks of desiccated corpses, bodies that had been aged years in only hours as all living essence was siphoned from them. The Primarchs of the Legionswere disgusted as the true understanding of the enemy they faced was revealed. The Nephilim fed on adulation. In the strategium of his flagship, the Vengeful Spirit, the Horus showed his brother Sanguinius, the Primarch of the Blood Angels, the plan that he had conceived to break the will of the Nephilim. Horus wanted the Blood Angels to march shoulder-to-shoulder with their cousins, cowing the aliens with the sight of an army of thousands of powerful Astartes rolling without pause to the gates of their last bastion. And then through those gates, over the battlements, not stopping, not pausing to parley or hesitate. "Like the ocean these things sprang from," Horus had said, "we will roll over the aliens, drag them down and drown them." The sheer bombast of the plan was its greatest strength, but Sanguinius had not been easily swayed to it. This blunt, brute-force approach was better suited to their more intemperate brother Primarchs, to Leman Russ or to Angron. Sanguinius felt that neither he nor Horus were so artless, so focused upon the target to the detriment of all else, but in the end he agreed. When the time came to enact their audacious plan, Horus and his Luna Wolves met the xenos army on the sparkling white plains of the Silver Desert. Before open hostilities began, Horus attempted to parlay with the Nephilim one final time, but the overconfident xenos refused to capitulate, casually informing the humans that they could not win. Horus informed the xenos commander that it had made a grave error, for it would be the Nephilim who would fall. The Luna Wolves would be the anvil upon which the xenos would break, and the Blood Angels would be the hammer. With lightning speed, the heavens screamed as a rain of ceramite Drop Pods tore through the outer atmosphere of Melchior and fell like flaming meteors towards the Silver Desert. Falling with them were Stormbird and Thunderhawk assault gunships that turned and wheeled through the air towards the gargantuan Nephilim encampment, carrying company upon company of the IX Legion. The speed of their assault was the key to victory; the alien invaders and their zealots had successfully been drawn out to confront the massed forces of the Luna Wolves, leaving the defences on their flanks thinned and permeable. But the xenos giants were not slow in their thinking, and the moment they understood that they had been duped, they would attempt to regroup and fortify. The Blood Angels did not allow that to happen. The Nephilim were broken and cut down, their cohesion shattered by the brutal deep strike. Caught between the brutal fury of two Space Marine Legions on Melchior’s shining sands, the Nephilim were finally put to the sword.
 * Compliance of Sixty-Three Nineteen (Unknown Date.M31) - The Imperial Compliance action of the world codified as Sixty-Three Nineteen (63-19) took place in the 203rd year of the Great Crusade. Forced off course by a Warp Storm, the Luna Wolves' 63rd Expeditionary Fleet discovered a system of 9 planets orbiting a yellow sun quite by accident. After entering the system they were contacted by a technologically-advanced human society based on the third planet. This world was ruled by a self-appointed "Emperor of Mankind" who claimed to be the predestined ruler of all the scattered remnants of humanity across the galaxy. He invited a delegation from the Imperial fleet to treat and pay fealty to him. The Warmaster sent his most favoured commander, Captain Hastur Sejanus and his Glory Squad to meet with this supposed "Emperor." Though initial negotiations appeared to proceed smoothly, they irrevocably broke down when the Astartes Captain dared to suggest that there was another, true Emperor of Mankind. Perceived as an insult, Captain Sejanus and his men were taken by surprise during a diplomatic parley and cut down. The death of Horus' favourite son and Mournival member would open an emotional chink in the Primarch's psyche that would later be exploited by First Chaplain Erebus of the Word Bearers Legion upon the Feral World of Davin during Horus' corruption by Chaos in the Temple of the Serpent Lodge. Though intensely grieved by Sejanus' death, Horus miraculously did not order an immediate retaliatory strike. Instead, he mobilised an Astartes "speartip" unit to stand by and prepare for a planetary assault. Horus then attempted to negotiate a second time by despatching Maloghurst and another contingent of Luna Wolves, but this mission also ended in disaster when Maloghurst's Stormbird was shot down and presumed lost. A great fleet of over 600 warships rose up from the planet's atmosphere to meet the 63rd Expeditionary Fleet, throwing down a challenge. The Warmaster responded in kind. The great naval battle that ensued is not recorded in detail in the existing Imperial records of this time, but eventually the Imperial fleet ultimately prevailed. The massive ground assault spearheaded by the Luna Wolves was led by First Captain Ezekyle Abaddon, as well as a half-dozen Titans which provided ground support while Assault Craft provided close-air support. The Luna Wolves were eventually able to close and penetrate the capital city's defences. The Luna Wolves fought their way inside the Imperial Palace until they came face-to-face with the supposed "Emperor." The false Emperor offered to surrender to the Imperial forces, but only to their overall acting commander, not his subordinate captains. The request was transmitted to the fleet, but Captain Garviel Loken of the 10th Company quickly realised that this was merely a ruse to draw Horus down to the Throne Room to be assassinated. 1st Company Captain Kalus Ekaddon, commander of the Catulan Reaver Squad, swiftly killed the man he believed to be the false Emperor. Then the true false Emperor revealed himself, striking with deadly force against those Luna Wolves that were present, and nearly succeeded in neutralising both Loken, Ekaddon and the other members of the Catulan Squad. He was only stopped by the timely intervention of the Luna Wolves' Primarch, as Horus teleported directly into the Throne Room and slew the false Emperor with a single, well-aimed Bolt Pistol shot to the head. The main part of the campaign was concluded with the death of the false Emperor. With the death of their leader, the main resistance on 63-19 collapsed, although there were some elements of the world's military forces that continued to wage a guerrilla war around the planet as well as three other worlds within the system. These resistance elements were eventually expunged through the efforts of the 63rd Expedition's attached Byzant Janizars Imperial Army regiment over the next few months. The last pocket of serious resistance to Imperial Compliance occurred in the Whisperhead Mountains located in the southern hemisphere. This last pocket of resistance would eventually be excised by Captain Garviel Loken's 10th Company over a period of three months. These hold-outs made their final stand within a formidable fortress carved out of the rock of one of the range's highest peaks. When the 10th Company fought their way inside the mountain fortress they discovered what appeared to be several primitive religious fanes or shrines. The Luna Wolves presumed that they were somehow connected to this region's superstitious worship of a being referred to as Samus. This being turned out to be a minor daemonic Warp-entity who had dwelled on and interacted with the inhabitants of 63-19 for many millennia. During the ensuing battle Samus possessed the body of one of the 10th Company's sergeants and was able to eliminate over a dozen Astartes and a number of Remembrancers that had accompanied the Luna Wolves before being cut down by the combined Bolter fire of Captain Loken and Sergeant Nero Vipus. The two Luna Wolves fired over 90 Bolter rounds into the possessed sergeant's body and then incinerated the remains with a Flamer. This was the first recorded incident in Imperial history of its military forces encountering the malefic powers of Chaos. The entire course of events was classified on the orders of the Warmaster, in order to hide the fact that an Astartes had turned on his fellow Battle-Brothers and that it was possible for the supposedly invincible Astartes to be corrupted by the malignant powers of Warp-entities, who were themselves a well-kept secret of the Imperium. Overall governorship of the world after it was brought into Imperial Compliance was given to General Rakris of the Byzant Janizars, while the adaptation of the cities and infrastructure of the world to Imperial standards was given over to Peeter Egon Momus. 63-19 was the first world that the newly-arrived Remembrancers of the 63rd Expedition added to their own records of the Luna Wolves' exploits.

Pre-Heresy
First as the Luna Wolves and later as the Sons of Horus, the XVI Legion kept much of their outward structure as it had existed since the wars for Terra and Solar unity, which had adhered closely to the Terran pattern laid down by the Officio Militaris before the unification with the Primarchs. The smallest formation within the "Logos Terra Militia" and therefore within the Luna Wolves was the squad. This consisted of a group of Luna Wolves under the command of a sergeant. Squads varied widely in both size and specialisation, with the majority of the units ranging between 10 to 20 Space Marines within the XVI Legion. Conversely very specialised squads, such as reconnaissance units, or those that might have suffered heavy casualties, might only consist of a handful of Space Marines in active service.

The specialties and equipment of squads in the Luna Wolves included all of those generally found in other Legions, including those designated Destroyer and Seeker units, shunned by some in lesser quantities. They also maintained considerable resources in terms of armour and vehicles, with tithed industrial worlds they had brought into compliance and good relations with the Mechanicum ensuring a steady supply of munitions and materials for the Legion, which spent such coin readily. Ever the gernalist and pragmatist Horus, upon his reconnection with his Legion, is thought to have adopted new squad formations having seen their effectiveness in other Legions. For example, it is noticeable that until the Lactrical Onslaught the number of shield-equipped Breacher squads was relatively low in the XVI Legion. The contribution of such units amongst the Imperial Fists forces cannot have escaped his notice. After the annihilation of the Lactrical, the number of such squads in the ranks of the Luna Wolves rose noticeably. Other anecdotal evidence of this adaptability and willingness to embrace new weapons of warfare can be found in Horus' vocal backing of the Tactical Dreadnought Armour project, with the result that his Legion was one of the first and most widely equipped with Terminator Armour and at the forefront of the development of tactics for its use in assaults.

The XVI Legion showed a preference for the use of Tactical Squads. Squads configured in this form within the Sons of Horus outnumbered all other squad types combine throughout the Great Crusade. Horus remarked on several occasions that there were few challenges of war that could not be met by, or did not require, the use of such units. The presence of Tactical-type squads designed to be held in reserve and unleashed once a weakness in an enemy line had been identified, trained in fire saturation and carrying additional close combat weaponry for use in overrunning enemy positions - the so-called Despoiler Squads - shows again the dominance of the Tactical Squad in Horus' tactical thinking. Such was the effectiveness of this subdivided tactic that its use was copied in several different Legions, such as the White Scars and Iron Warriors, who field Despoiler squads of their own.

The heart of the Luna Wolves Legion was the Company as the principal military division. Made up of a grouping of squads under the leadership of a captain, the Company was the base currency of campaigns and battles. There was no fixed strength for a Company within the Sons of Horus. While other Legions codified and enforced strict limits on the size of similar formations, this was not the case amongst the Sons of Horus, which had begun in more regimented form, but had become increasingly ad hoc in structure and disposition over time. Company strengths as small as 36 and as large 972 were recorded by datafactors during the Legion's action against the Dasim Patrimony, for example.

The configuration of squad types within a Company varied widely as its strength. Some comprised almost exclusively of Tactical Squads with a few Support Squads. Others were an eclectic mix based on the varied requirements of campaigns and the will of Horus. Tactical Squads made up half this strength numerically (with the Legion placing in general great importance on the use of Tactical Squads in every deployment). the rest consisted of two veteran units, three reconnaissance units, a heavy support squad and multiple batteries of support weaponry. The 1st Company showed even greater variation. Small in number it contained two distinct sub formations: the Justaerin Terminator squads formed one part and the Catulan Reaver Assault Squads the other. Both sported the black armour worn only by this elite company and each was led by a captain under the overall command of the First Captain. Used in combination the 1st Company exemplified Horus' predilection for precise and overwhelming attacks against strategic targets.

In other Legions a Company would form par of further layers of organisation, variously referred to as battalions, cohorts, chapters, regiments or by any number of other titles. Horus seems to have preferred to avoid this extra layer of fixed organisation, which eroded over time in the Legion and was largely academic by the time of their transition to the Sons of Horus. Instead of a formal structure he would group Companies and individual units together as required for the execution of a particular campaign. The commander of such a formation would usually be a senior captain. If the formation was especially large then other captains would take on the role of lieutenants to the overall commander until the completion of the campaign. These formations rarely had formal titles, but the Luna Wolves commonly referred to formations intended to prosecute a rapid assault as "Speartips." In eschewing formality and fixed structure above the basic level of the Company, Horus demonstrated his pragmatism and his preference for waging war with judged precision. Within the Luna Wolves squads also commonly had their own honorific or epithetic titles rather than simple numerations: Illuminators Prime, Death Makers, Jerrok's Reavers, the First Sons, and similar, while some were name for the sergeant or chieftain that led them where their leader's own reputation was strong enough alone. Many of these titles betrayed the culture of Cthonian gang honours and the tradition of reputation and internecine warfare from which they sprung. This had over the years grown steadily stronger within the rank and file of the Legion's intake.

Legion Command Hierarchy
As with all Legions Horus' command over his own Legion was absolute. Beneath Horus were his captains, beneath them were the unit sergeants, and where a formation of squads came together for a purpose, the informal rank of "Chieftan" was given to the sergeant granted field command authority, a matter not always of seniority, but rather selection of the best or most suited for the task at hand; an approach which fitted well within the Legion's pragmatic and sometimes impulsive approach to warfare. Beneath them were the battle-brothers of the Luna Wolves. This simple hierarchy belied the truth of matters when applied in practice within the Luna Wolves. Within each rank prestige and personal reputation counted for much within the brotherhood of Space Marines. There were distinctions between those who fought with the Legion for longer, between those who had fought in different campaigns, between those who had received certain honours, and between ordinary squads and those who formed a captain's honour guard. Beneath the surface of this simmered other divisions, not easily visible to the outsider, divisions of blood and origin, divisions that the mere act of becoming a Space Marine should have washed away, but for the redubbed Sons of Horus it did not in many cases and would eventually bear bitter fruit.

The rank of captain within the Legion also held subtle variations of authority. Generally those in command of a lower numbered Company outranked those who had once had overall command of a campaign was superior to those he had commanded. At the top this no-explicit, but very real hierarchy, were those captains who were Horus' closest advisors and in particular the Captain of the 1st Company, who served as his Primarch's principal field officer. This was the Legion's Mournival, the quartet of Astartes who served as Horus' closest advisers and companions within the XVI Legion that existed outside the regular command structure. Before the Heresy the final Mournival included members Garviel Loken, Horus Aximand, Tarik Torgaddon and Ezekyle Abaddon. The Mournival served as an advisory body to Horus in both military and political matters, but in truth its members held no formal power above that of the other company captains.

Held together by Horus' personal charisma and brilliance as a leader, the command structure of the Luna Wolves proved highly effective, adaptable and resilient. Combined with the Legion's skill in rapidly concluding campaigns it allowed it to flow from one victory to another, forming and reforming to meet each new challenge. Each Luna Wolf knew his capabilities and the capabilities of those around him, both by given rank and personal repute, capabilities that were enshrined in a hierarchy determines by deeds rather than the demands of formality. Effective as it was one cannot help but notice the importance of personal prestige and the pack-like sorting of authority as a hallmark of the Legion, and upon occasion the source of some conflict and vendetta within the ranks, a seed of division to come. As the character of the Legion was an echo of its Primarch, so one can perhaps see the flaw of the father in the pride of his sons. So it was that when Horus fell from grace, so too did his sons, and their faults, long-sleeping, multiplied and grew to consume them: pride, ambition, the desire to be greater than any other and the savagery and merciless will to make such dark dreams manifest.

Specialist Ranks & Formations

 * The Mournival - The Mournival were Horus' most trusted advisors and confidants. Consisting of four chosen captains, the Mournival existed outside the rest of the XVI Legion's command structure. Together the Mournival functioned as the soul of the Luna Wolves, and later the Sons of Horus, supporting their Primarch and steering the Legion's temperament and decisions. The Mournival had many important responsibilities which included making sure that the Legion and its Primarch lived up to their standards of moral excellence and the Emperor's vision of the Imperial Truth in prosecuting its duties and helping the Primarch devise strategies for more effectively carrying forth the Great Crusade. The Mournival on occasion even provided Horus the means to posture politically as a means to save face or present a certain united front when in the presence of the XVI Legion's Imperial allies and enemies alike. Horus relied on the Mournival to balance his decisions with questions and different perspectives. In this way the four captains were a combination of counsellors, confidants and naysmiths. It is known that here was an element of ritual to the bond between the Mournival brothers: meetings of the Mournival took place in moonlight, a different phase of the moon was graven on the helm of each brother, and its oaths of brotherhood were made over the reflected image of a moon. The origins of the Mournival are unclear although there are parallels with the rites of brotherhood amongst the Jutigran clans of Terra and the practice of the gene-cults of Luna. Whatever the Mournival's origins its existence within the Legion certainly lies in in the early decades of the Legion's creation, and it is known to have persisted even after the Istvaan III Atrocity.
 * Justaerin Terminator Squads - The Justaerin Terminator Squad was one of two distinct sub formations of the elite 1st Company. Led by the Legion's First Captain, the black-armoured Justaerin were the pride of the XVI Legion. Tasked with forming the "point of the spear" of the Legion, they went where the fighting was thickest, their attack directed usually at destroying the heart of an opposing target or conducting the decapitation strike of an enemy force. Early proponents of the use of Tactical Dreadnought Armour, many entered combat as Terminators, relying on the resilience this gave them to smash aside any resistance and close in for the kill.
 * Catulan Reavers Assault Squads - The Catulan Reavers Assault Squads were the other sub formation of the elite 1st Company. They too, sported the signature black armour which denoted their specialisation in harrowing actions and hit-and-run tactics. They were led by a captain under the overall command of the First Captain. They also made extensive use of Terminator Armour, taking advantage of its additional protection and ability to smash aside any opposition. Used in combination, these two elite formations of the 1st Company exemplified Horus' predilection for precise and overwhelming attacks against strategic targets.
 * Despoiler Squads - These Tactical-type squads were designed to be held in reserve and unleashed once a weakness in an enemy line had been identified. Trained in fire saturation and carrying additional close combat weaponry for use in overrunning enemy positions, these so-called Despoiler Squads showed the dominance of the Tactical Squad in the Warmaster's tactical thinking. Such was the effectiveness of this subdivided tactic that its use was copied in several different Legions.
 * Destroyer Squads - Considered dishonourable by some Legions who made little use of them or eschewed them altogether, Destroyers were equipped with and expert in the use of otherwise proscribed and forbidden weaponry. Alongside certain factions of the Adeptus Mechanicus, only Destroyer cadres had the license to use these weapons in the forces of the Imperium by the Emperor's command. Rad-weapons, bio-alchem munitions and the burning horror of Phospex were amongst the forbidden weapons in a Destroyer Squad's dark arsenal, weapons which irrevocably tainted the ground upon which they were used. Marked by their fire-blackened and chem-scalded armour, Destroyers were often shunned and deemed somehow tainted by their fellow Battle-Brothers in many Legions and were considered at best a necessary evil, although the effectiveness of their relic-weapons in cracking especially difficult enemy defences could not be denied.
 * Seeker Squads - Seeker Squads are comprised of a specialised force of Space Marines whose principal task on the battlefield is to identify an enemy's command structure, its warlords, officers, priests, demagogues, whatever they may be, and slay them with a well-placed bolt round while the battle rages round them. The Alpha Legion are said to have first crystallised this tactic and squad configuration, which had since, with the Emperor's approval, spread to the other Legions, although its use sat poorly within the combat doctrine of some. Equipped with special issue ammunition to assist their efforts, Seeker Squads are primarily composes of the finest shots within the Legion, as a Seeker strike force will often only have small window of opportunity to take down their targets at close range, rather than have the luxury of distance.

Notable Legion Members

 * Iacton Qruze, "The Half-Heard" - Iacton Qruze was the Captain of the Luna Wolves 3rd Company, a very old Space Marine who was a native of Cthonia. By the time of the Horus Heresy he was one of the only Cthonian Astartes still serving in the XVI Legion who remembered what it was like when the Luna Wolves had served only the Emperor before Horus had been rediscovered by his father. Qruze had been a captain of the Luna Wolves since the Legion's inception and was even a veteran of the Unification Wars on Terra. Considered ancient by dint of his length of service to the Legion as well as his continued die-hard loyalty to habits of the Legion from the time of its Terran past that he could not seem to break. Qruze, like most Terran Astartes in the Traitor Legions, remained loyal to the Emperor when his Horus turned to the service of Chaos in pursuit of his own ambitions. Recognising that the Sons of Horus no longer represented the Astartes he had once known, Qruze rescued the civilian Remembrancers Mersadie Oliton and Euphrati Keeler as well as the Senior Iterator Kyril Sindermann from Horus' massacre of civilians on his flagship the Vengeful Spirit and fled with them to the Frigate Eisenstein during the virus-bombing of Istvaan III. During the flight of the Eisenstein to Terra, Qruze formed a firm bond with the former Death Guard Battle-Captain Nathaniel Garro, the pair were told by Malcador the Sigillite, the Regent of Terra, that they, along with the Sister of Silence Amendera Kendel, were to form the beginnings of an organisation that would utilise "men and women of an inquisitive nature, hunters who might seek the witch, the traitor, the mutant, the xenos" -- later known as the Imperial Inquisition.

Legion Colours
As if to mark a break from the wars of the past the armour that the first warriors of the Legiones Astartes went to war in was cast in storm cloud grey, and bore only the thunderbolt and lightning marks of Imperial unity. Over time Legions gained their own marks of distinction and character, and names. When the XVI Legion were given the epithet of the "Luna Wolves" following the successful First Pacification of Luna they began to wear pale off-white ivory coloured armour with black trim. The two renowned squads of the elite 1st Company, the Justaerin and Catulan Reaver squads wore black coloured Power Armour, in sharp contrast to the white of the rest of the Legion. One avatar of the increasing influence of the Legion's Cthonian brothers was the late reemergence of Cthonian gang-sigils graven into particular Space Marine's armour recording notable kills and deeds, as well as to which Company they belonged.

Legion Badge
The XVI Legion's badge was a wolf's head imposed over an inverted crescent moon when they were known as the Luna Wolves.