The icon of the Imperial Army

The original Therion Cohort was an illustrious regiment of the Imperial Army, one that has had the honour of fighting alongside the Emperor of Mankind Himself during the 30th Millennium. Attached first to the 376th and then to the 27th Expeditionary Fleets under the Raven Guard Space Marine Legion and the command of the Primarch Corvus Corax, the Therion Cohort were sacrificed in a diversionary attack on the forces of the rebellious Warmaster to allow the extraction of what remained of the Raven Guard Legion in the wake of the Drop Site Massacre.

The reconstituted and severely augmented Therion Cohort would then honour their oath of servitude and allegiance to the Emperor and officially declare for the Golden Throne. Like their tutelage Legion, the Therion Cohorts decided not to sit idle but to seek out the enemy and confront him, coordinating all of their actions with the Raven Guard during the fierce fights of the Horus Heresy. Despite their name, there is no tangible proof that the Therion Cohort followed the Solar Auxilia pattern.

Regimental History

The Therion Cohort numbers perhaps amongst the most famous regiments of the Imperial Army, its name being honoured in the same proportion as the Lucifer Blacks or Malcador's Chosen. The Therions have become a byword for discipline and faith in the Imperial cause, even having gained the selective honour of fighting alongside the Emperor of Mankind Himself. Attached first to the 376th Expeditionary Fleet, this most distinguished unit of the Imperial Army would go on to serve the Great Crusade alongside the 27th Expeditionary Fleet.

Fighting along the Raven Guard Legion, the Therion Cohort and the XIX Legion formed lasting bonds of honour and assistance, fighting together in such notorious Compliances as the initial Istvaan III Compliance some ten years before the events of the Horus Heresy. The Cohort’s history has always been one of selfless sacrifice. As the Raven Guard was trapped on the surface of Istvaan V, it was thanks to the efforts of its Praefactor, Marcus Valerius, that a successful rescue mission could be mounted. Truly miraculous, the timing of the Therions intervention saved the remaining Raven Guard from being slaughtered by the World Eaters. Corvus Corax was saved, ensuring that at least one of the Loyalist Primarchs had survived the Dropsite Massacre. To ensure that the Raven Guard would live to fight another day, the Therion Cohort did not hesitate to sacrifice itself to give Commander Branne the opportunity to save his Primarch.

With the Cohort and its attending fleet entirely destroyed, the sole survivors, Praefactor Valerius and his manservant Pelon, accompanied the Raven Guard to Terra and petitioned the Council of Terra for the permission to raise a new Cohort. With this new augmented Therion Cohort, Marcus Valerius would prosecute the war against those who had sided with the Warmaster.


Therion is a highly populous world within the Segmentum Solar located some weeks of Warp-travel from sacred Terra itself. Therion had both maintained a high degree of technology and urbanisation during the dark times known as Old Night. Therion is a world of sophistication, tradition and etiquette; an old world by all accounts as it is believed to have been colonised in Mankind's distant past. For eighty generations, the Therions ruled themselves before peacefully accepting Imperial Compliance and joining the growing ranks of the Imperium of Mankind. In exchange, Therion could maintain much of its traditions, although conservative hardliners still miss the day where time was measured by the old Therion Calendar, roughly equivalent to 2.8 Terran standard years. Therion is ruled by a highly organised and stratified military aristocracy.

To the eyes of a Terran scholar the culture of Therion would seem oddly familiar as it includes many elements drawing back to the ancient Romani-people of old Terra, Therion's Imperial Commander even claiming the title of "Caesari". As with most military aristocracies, the title of Planetary Ruler is hereditary and has remained with the Valerius-family for many centuries. Each nobleman is required to serve a time in the Therion's military, which special consideration given to the off-world regiments collectively known as the Therion Cohort.

Notable Campaigns

  • Istvaan III Compliance (994.M30) - As part of the 27th Expeditionary Fleet, the Therion Cohort participated in the Compliance of the world of Istvaan III. The local Istvaanians had a highly powerful, advanced and disciplined army to call upon, numbering even renegade Psykers known as Warsingers that were so powerful that they even kept in check the might of the Emperor’s Legiones Astartes. Under the command of Corvus Corax, the Istvaanians were ultimately crushed at the Redarth Valley, the Primarch having called upon the 800 companies of Raven Guard Space Marines that comprised the XIX Legion as well as their allies from the Therion Cohort and heavy assault cadres drawn from both the Legio Victorum and the Legio Adamantus to secure this Imperial victory. In a great ceremony during which a selected delegation of Istvaanians publicly surrendered before the Primarch, Corax formally acknowledged the role of the Therions in this battle.
  • Raven’s Flight (005.M31) - Having been left behind on Deliverance by the XIXth Legion before their departure for Istvaan V, the Therion Cohort followed the steps of the Raven Guard into the Istvaan system. At the initiative of Marcus Valerius, the Therion Cohort’s Praefactor who had been plagued by prophetic dreams, the Therion Cohort and the Raven Guard’s reserve Company under Commander Branne disregarded their respective orders and decided to rush to their Primarch’s aid. However in order for the Avenger to approach Istvaan V covertly, the Therion Cohort had to be sacrificed in a diversionary attack, which marked the end of the original Cohort.
  • Siege of the Perfect Fortress (Unknown Date, circa 007.M31) - Located on the world of Narsis, the so-called "Perfect Fortress" had been erected by the III Legion, the Emperor's Children, during the Great Crusade-era. As its name may indicate the Perfect Fortress was a military base, but also a Hive city harbouring many millions of inhabitants where elegant buildings and colonnades hid both administrative buildings as well as tanks and weapons depots, and where ornate balustrades revealed themselves as redoubt and every balcony was a perfect firing position on pre-planned kill-zones. Taking the Perfect Fortress would be an arduous task, a task which in truth lay beyond the capabilities of the severely depleted Raven Guard to take alone. It was then fortunate that shortly after the Kiavahrian Uprising, the ranks of the XIX Legion were swelled by the reconstituted and vastly expanded Therion Cohort. Under the command of their newly-appointed Vice-Caesari, Marcus Valerius, the Therion Cohort would then take the brunt of the assault. Corax’s however asked for a heavy sacrifice from the Therion Cohort: to land far away from the Perfect Fortress and march on it while weathering its considerable fire power. For three long days, the Therion Cohort assailed the Perfect Fortress before their losses forced them to retreat. This was all the enemy commander, Captain Luthris, had been waiting for, as the Emperor’s Children were already positionned to counter-attack. Conducting an organised retreat while being pursued, and in many places massacred by the Emperor’s Children, only stands as a testament as to the Therions spirit and discipline, as through the sacrifice of thousands of their numbers, the Therion Cohort had achieved their mission: to draw the enemy out. As the Raven Guard finally showed themselves and descended upon the surprised sons of Fulgrim, the Emperor’s Children were swiftly defeated and the so-called "Perfect Fortress" fell within the day. This highly symbolic action would not only mark a severe defeat of the traitorous III Legion, but also heralded the return of both the Therion Cohorts and the XIX Legion to the front lines of the war against the Warmaster.
  • Reconquest of Euesa (Unknown Date, circa 009/010.M31) - Located in the Vandreggan Sector, the world of Euesa was the latest target in a series of attacks led by the joined forces of the Raven Guard and the Therion Cohort. A first attack on its capital, designated as Milivan, had failed and the Therions had lost more than seventeen hundred men in this rushed attack. However, the campaign plan dictated that Milivan and its orbital batteries be silenced within the next eighteen hours in order to allow the Raven Guard to conduct a lightning attack on the fortified complex where the planet’s rulers had taken refuge. By the time of the Reconquest of Euesa, the Therion Cohort formed the core of an Imperial Battlegroup, consisting of the Therion Cohort, the Capricon 13th Suppression Regiment and its heavy tanks and the men and women of the Lothor Pioneer Corps. The army was supported by several Titan Maniples drawn from the Legio Vindictus as well, all heeding the words of one man: Marcus Valerius. With preparations for a renewed assault well on its way, Valerius was against troubled by prophetic dreams, showing him in the clutches of a hydra. Acting upon these dreams, but not daring to mention them to anyone save for his manservant, Marcus Valerius withdrew several companies of Therions, the Iron General and two Battle Titans to act as reserve. These he placed under the command of his younger brother, Antonius. While the other officers had some misgivings towards this, as it would considerably weaken their strength for the main attack, Marcus Valerius insisted upon taking precautionary measures in case the army’s flank was unexpectedly threatened. This proved to be the case as traitorous Imperial Army regiments approached the army’s rear using recovered Raven Guard ident-tags. Forewarned by his dreams, Marcus Valerius ordered his brother to engage the enemy which was promptly wiped out. Milivan was taken within the morning and the true Raven Guard conducted the final attack unimpeded.

Regimental Doctrines

For most of its operational history, the Therion Cohort has operated alongside the XIX Legion of the Emperor's Legiones Astartes; first as part of the 27th and then of the 376th Expeditionary Fleet. Whilst it is widely known that the Therion Cohort has been granted the rare privilege of fighting alongside the Emperor of Mankind, records as to its organisational pattern in these early years of the Great Crusade have been entirely lost. What is known is that the modern-era Therion Cohort, which fought alongside the Raven Guard Legion during the latter part of the Great Crusade and the years of civil war, mostly operated as a single heavy infantry regiment. The Therion Cohort is known to have used the now commonplace Sentinel walker for scouting and patrolling missions, but its true strength resided in its plethoric ranks: spearheaded by Raven Guard strike squads and usually supported by heavier units such as the Titans of the Legio Vindictus, the Therions were mostly required to take to the field en masse and crush or draw out the enemy with its numbers. The Therion Cohort was well-known for its discipline even under the direst of circumstances and their tenacity in the face of the enemy has always been justly famed.

The basic organisational unit of the Therions has always been the Company, a unit of a hundred men which were banded together into larger battalions of two thousand men which were commonly designated as Phalanxes. Each Phalanx was commanded by a Praefactor, which was the highest rank within the Therion Cohort until the Warmaster’s rebellion. This may well indicate that indeed the original Cohort was a mere two-thousand strong infantry regiment, but records indicate that by the time of the Istvaan III Compliance, the Cohort’s numbers easily reached into the tens of thousands. Historically, the Therion Cohort exclusively consisted of volunteers, which stands as a testament to the Therion’s discipline and loyalty to the Golden Throne. Indeed such was the demand within Therion’s population that for years on end, Therion’s ruling Caesari had to refuse the enrollment of many volunteers. As the civil war soon engulfed the Imperium and the Therion Cohort was sacrificed to save what remained of the Raven Guard Legion, the Therion Cohort was founded anew on its homeworld. More akin now to an entire Battlegroup than to a single if oversized regiment, this third incarnation of the Therion Cohort - which nevertheless kept its original name - would distinguish itself even more than its predecessors.

Notable Therion Cohort Personnel

  • Caesari Valentinus Valerius - Valentinus was a proud member of the Valerius-family, the planetary rulers of Therion and the youngest Caesari to have ever been elected. Father to both Marcus and Antonius, Valentinus was only in his late fifties when Warmaster Horus turned against the Imperium. Short of build and fair of hair, Valentinus was a competent and beloved leader, a former Praefactor of the Therion Cohort and an experienced officer. Valentinus had fought in a great many battles of the Great Crusade, both alongside the Raven Guard and the Emperor of Mankind. These battles had however left their mark on him -- he had lost one leg, half of his hand and one of his ears to the enemy, all of which required augmentic replacement. Wishing nothing more than to return to the battlefield, the pressing matters of ruling Therion and the insistence of his wife, kept him from waging war alongside his sons.
  • Sub-Caesari Marcus Valerius - Oldest son of Therion's ruling Caesari, Marcus was, however, not the Caesari's first child, yet as first male and eventual heir to the title of Caesari, Marcus has always had to follow in his father's footsteps. As Valentinus Valerius before him, Marcus would lead the planet's most honoured regiment, the Therion Cohort to fight amongst the stars and in the Emperor's name. Drilled and prepared for this task since birth, Marcus Valerius was directly promoted to commanding officer of the Therion Cohort with the grade of a Praefactor of the Imperial Army. Although it is unclear when this change of leadership occurred, Valerius saw much action alongside the Raven Guard Legion until the dire events which have since entered history known as the Dropsite Massacre. Although Imperial Army units would take to the black sands of Istvaan and Valerius and his Therions volunteered to do so, the Primarch of the XIX Legion flatly refused -- in a war between Astartes, his argument went, a mere human would simply be swept aside. Ordered to remain on Deliverance, the Raven Guard's headquarters orbiting their homeworld, the Therion Cohort would rest, reequip and wait for news of what everybody expected to be a swift Imperial victory. As the weeks extended into months, Marcus Valerius began to be plagued by dreadful and recurring nightmares. The images these nightmares carried with them were all laden with impending doom -- a burning horizon and a blood-covered raven brought low. The recurring nature of these dreams which for a lack of a better world seemed prophetic bore heavy on Valerius' mind. Unable to stand it any longer, Valerius entrusted his visions to his manservant, Pelon, a man of trust which was oath bound to keep his master's secrets at all costs. Valerius then took his doubts to Commander Branne, the commanding officer of the Company of Raven Guard that Corvus Corax had ordered to remain on Deliverance as a precautionary measure. Infuriated by what he considered was Valerius' lack of faith in the Emperor's finest warriors, Commander Branne refused to take any action or even join the punitive expedition over astropathic choir to confirm their current status. Yet, the dreams still continued to visit Valerius each and every night, and still no news of the expected victory came down through the communication channels. Confronting Commander Branne with his dreams, Marcus Valerius narrowly missed being executed for witchcraft, but his words had awoken Branne's own doubts. Still the Raven Guard refused to go against his Primarch's order. Instead, Branne used his full authority as Regent of Deliverance to get the Therion Cohort and Valerius to stay put. However the situation could not last. With still no news of the XIX Legion's fate, Marcus Valerius single-handedly decided for the Therion Cohort to mobilize. If Commander Branne would not move to aid his Primarch, the Therion would. At the last possible moment, after a tense stand-off where Commander Branne threatened to blast the Cohort's ships from Deliverance's sky if they did not heed his words, Marcus Valerius took to the vox and convinced Branne to join them. He would take full and sole responsibility for the violation of their orders and would resign from his tenure if his actions would prove unnecessary. However, as events would come to pass, Marcus Valerius' prophetic dreams were correct. Far from winning the battle against Horus and the three Legions he had gathered around him, the Raven Guard, Iron Hands and Salamanders Legions had been betrayed by their brothers and almost completely annihilated. Those remaining Raven Guard, now numbering less than 3,000 warriors, were being mercilessly hunted down by the World Eaters, and had been prolonging their dire fate for nearly ninety days, but their time was measured. Commander Branne and Praefactor Marcus Valerius arrived just in the nick of time to extract the Raven Guard, which were gathered for a final, if ultimately, futile last stand against Angron's blood-maddened hordes. As the Therion's supporting aircraft held back the World Eaters, Legion Thunderhawks and Storm Eagles extracted the Primarch and the rest of the survivors, but to reach the planet unheralded Valerius had to sacrifice his entire flotilla in a diversionary attack on Istvaan III. None of the Therions survived except for Marcus Valerius and his manservant Pelon, which Commander Branne had ordered transferred to his own Battle Barge, the Avenger. Resolute to continue the fight, Marcus Valerius would travel back to Therion and raise a new augmented Therion Cohort which he would then command throughout the rest of the Horus Heresy.
  • Praefactor Antonius Valerius - Second son of Valentinus Valerius and younger brother of Marcus, Antonius Valerius was an important figure within the Therion Cohort. Taller than his father and his brother, Antonius' face radiated confidence, an ability that had not been diminished by the gunshot wound that crossed his right cheek. Ascending to the rank of Praefactor of the Therion Cohort following his brother's nomination as Vice-Caesari, Valerius proved to be a sound tactician and a good fighter, quickly becoming a figure of inspiration for his men. Serving under his brother did not seem to bother him, the two siblings working in tandem would help to gain much honor as they were both covered in glory throughout the bloody battles of the Horus Heresy.
  • Praefactor Magellius - Commander of the Therion's Second Phalanx during the Siege of the Perfect Fortress. Slain by the Emperor's Children during the Siege of the Perfect Fortress on Narsis.
  • Praefactor Tigurian - Commander of the Therion's Third Phalanx during the Siege of the Perfect Fortress on Narsis. Slain in the Emperor's Children-led counter-attack.
  • Tribune Calorium - Assigned as Marcus Valerius aide in the wake of the second foundation of the Therion Cohort, Tribune Calorium was Valrius' designated communication specialist, keeping the Sub-Caesari appraised of the overall situation and relaying his orders to distant parts of the battlefield. As stoic as every Therion-born, Tribune Calorium stood ever at Valerius’ side, not above firing his own weapon or to retrieve a lasgun in order to fight. Tribune Calorium was wounded during the Siege of the Perfect Fortress on Narsis.
  • Vice-Tribune Callista - Tactical advisor and member of Marcus Valerius' entourage on Narsis. Believed slain in the fierce counter-attack during the Siege of the Perfect Fortress.
  • Sub-Tribune Pelon - Manservant and aide to Marcus Valerius, Pelon has swiftly learned to mind his place amongst the higher echelons of Therion's high aristocracy -- a privilege considering his own humble origins. Having accompanied Marcus Valerius since his tenure with the Therion Cohort, Pelon accomplishes the every-day mundane task and maintains many contacts within the Expeditionary Fleets and the black market as to ensure his master lacks of nothing. Driver, dry-cleaner, secretary and cook of the Praefactor, Pelon and Marcus have reached some kind of friendship, the Praefactor occasionally asking for his manservant's advice and opinion. Pelon became the true confident of his master when Marcus Valerius began to have his visions. As he himself, was a convert of the Lectitio Divinitatus, Pelon would introduce his master to its teaching, confirming his beliefs that the Emperor was sending him these visions. His enduring loyalty has allowed him to be rewarded with the title of Sub-Tribune, an extraordinary feat for a man of such humble origin as Pelon.

Notable Wargear

The initial Therion Cohort was a single Regiment of the Imperial Army, however with the outbreak of the galactic civil war known as the Horus Heresy, the reconstituted Therion Cohort was more akin to an Imperial Battlegroup. Following the Therion’s and Raven Guard’s first victories, other loyalist Imperial troops soon rallied around the Cohort, warranting Marcus Valerius’ promotion to Vice-Caesari. With the progressive increase in manpower and material, the Therion Cohort was soon able to field sizeable war-engines.

  • Contemptuous - The Contemptuous was a Capitol Imperialis, a super-heavy command vehicle used as his headquarters by Vice-Caesari Marcus Valerius during the assault on Milivan, the capital-city of the world of Euesa. Commanding from the front-lines as he prefered to do it, Marcus Valerius ordered the Contemptuous to attack the city’s main defence - a so-called lightning shield which had already repelled one of the Therion’s assaults -, overwhelming its generators through the firepower of its Behemoth Cannon. Taking fire from an enemy Warlord-class Battle Titan, the Contemptuous’ shields held long enough for allied Titans of the Legio Vindictus to destroy it. The origins of the Contemptuous and its twin - the Iron General - remain mysterious as it is unclear under which circumstances and indeed when the Therion Cohort acquired these powerful engines of war.
  • Iron General - The Iron General is the second Capitol Imperialis in service to the Therion Cohort. Usually commanded by Antonius Valerius, brother to the Vice-Caesari, the Iron General was kept in reserve during the assault on Milivan, thus ensuring the full destruction of an enemy force that had threatened the army’s flank and succeeded in approaching through the falsification of allied identification-tags.

Therion Appearance

Records on the appearance of the Therion Cohort are fragmentary at best, and few detailed accounts have survived the eons between the 30th Millennium and today. It would appear that the Therions favoured a combination of gold and red, both colours being extensively represented on its banners. The officers such as Praefactor Valerius commonly wore a red sash as part of their uniform and as a mark of their rank. In fact, at the time of the Great Crusade, wearing the red sash of the nobility without being entitled to do so consisted the sole capital crime still enacted on Therion. Flak-vest and other pieces of armour seemed to have been golden as a matter of tradition, whilst bodyguards to the Therion nobility were rather issued with golden and heavily decorated suits of Carapace Armor. These same bodyguards have also been noted to wear white trousers, which must have made for quite a sight on the battlefield. As a regiment of long-standing and noble history and proud martial traditions, it is quite probable that the Therion Cohorts has entirely eschewed the use of camouflage techniques as some Chapters of the Adeptus Astartes still do in the 41st Millennium.


  • Deliverance Lost (Novel) by Gav Thorpe
  • The Divine Word (Short Story) by Gav Thorpe, in Legacies of Betrayal (Anthology)
  • Raven’s Flight (Audio Book)
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