"They were forged for Mankind's darkest hour -- and that hour is upon us."
Ultramarines Primarch Roboute Guilliman, Lord Commander of the Imperium
UM Primaris Space Marine

Primaris Space Marine Intercessor of the Ultramarines Chapter in Mark X Tacticus Pattern Power Armour wielding a Mark II Cawl Pattern Bolt Rifle

The Primaris Space Marines are a new breed of transhuman warriors developed across the span of ten thousand standard years by Archmagos Dominus Belisarius Cawl on Mars on the order of Primarch Roboute Guilliman in the days immediately after the Second Founding in the early 31st Millennium. Cawl used the genetic template of the original Space Marines created by the Emperor for His Great Crusade as the starting point for the development of these new Astartes.

Primaris Space Marines are bigger, more resilient, physically more powerful and possess faster reaction times than their original Astartes counterparts. Primaris Astartes are also implanted with 22 rather than 19 gene-seed organs, and their gene-seed is more resistant to mutation than that of their predecessors. They were deployed across the galaxy by Guilliman and Cawl during the Indomitus Crusade after the opening of the Great Rift where they were used as reinforcements for existing Chapters of Astartes or were used to found all-new Chapters comprised solely of Primaris Marines.


"Through the artifice of the Martian priesthood were these warriors created. By the grace of the almighty Emperor are they given now to you. Silence your questions and instead rejoice at the honour done to you this day. You are handed the gift of hope by the immortal Master of Mankind Himself, and you will accept it with sincere and solemn gratitude lest you be taken for the traitors that you profess to hate."
— Sanash Gallimedan, Emissary Imperatus to the Hammers of Dorn Chapter
Primaris Astartes Mars

Belisarius Cawl and Roboute Guilliman, deep beneath the surface of Mars, oversee the final stages of development of the Primaris Space Marines

For ten millennia, Archmagos Dominus Belisarius Cawl has been working on a task set for him by the Primarch Roboute Guilliman before he was mortally wounded by the Daemon Primarch Fulgrim in the days after the Horus Heresy: a new legion of transhuman warriors. Developed on orders from Guilliman 100 standard centuries past, Primaris Space Marines were diligently developed and perfected by the Priesthood of Mars during the long intervening millennia.

As an optimist, but never a fool, Guilliman learned from the mistakes of the Horus Heresy, and he foresaw that the Forces of Chaos would never relent in their aim to bring the Imperium low. He anticipated that devastating times would once again engulf the galaxy and knew that warriors resilient enough to stand against them would be needed as never before. That time has surely come. Now, as the Imperium of Man is poised on the brink of annihilation at the hands of Chaos, his task is at last complete.

The Primaris Space Marine is a new generation of hero for this, the darkest age in the Imperium's history. These warriors are the next step in the evolution of the Emperor's Angels of Death -- genetically altered from their brethren to be bigger, stronger and faster -- timely reinforcements for the Imperium's armies as their enemies close in for the kill in the wake of Abaddon the Despoiler's 13th Black Crusade and the birth of the Great Rift dividing the Imperium in two.

Primaris Astartes Stasis

Nearly completed, the gene-forged Primaris Space Marines lie in stasis, waiting to be awakened from their long slumber.

To aid them in battle, these gene-forged warriors are equipped with new arms and armour forged on Mars itself, such as the Mark X Tacticus Pattern Power Armour worn by the Primaris Space Marine Intercessors, which combines the most effective elements of ancestral Horus Heresy patterns of battle-plate with more recent developments in Power Armour technology; the Mark II Cawl Pattern Bolt Rifle, the archetypal firearm of the Adeptus Astartes, now re-engineered, re-crafted and perfected; the Mark III Belisarius Pattern Plasma Incinerator, a new refined Plasma Gun; Redemptor Dreadnoughts, the Overlord gunship, and Repulsor grav-tanks.

At the dawn of the Indomitus Crusade to retake the Imperium from the advancing armies of Chaos and xenos alike, Lord Commander of the Imperium Roboute Guilliman gathered his new armada, along with elements of the Adeptus Custodes, a small contingent of the Silent Sisterhood and a vast war host of Primaris Space Marines as he fought to liberate the scattered bastions of the Imperium. Some, Guilliman had forged into new Space Marine Chapters, whole brotherhoods comprised only of these new transhuman warriors. Others he offered to the existing Space Marine Chapters. Many Chapter Masters welcomed their Primaris brethren into their ranks, accepting the new reinforcements gladly. Others, though, viewed these new creations with suspicion or outright hostility, claiming that the Emperor's work should never have been meddled with by mere mortals.

Fortunately, the Emissaries Imperatus, a Shield Host of the Adeptus Custodes, the elite bodyguard of the Master of Mankind, stepped forward to intercede, stating that the gift that was the Primaris Marines was the will of the Emperor. As "Heralds of the Golden Throne," they accompanied Guilliman's Crusade, many of them taking to the air as Vertus Praetors, the quicker to deliver messages of reinforcement to the embattled Space Marines. The presence of the Adeptus Custodes also ensured that even the most traditional Chapters accepted the Primaris warriors into their ranks. One does not decline a gift from the Emperor's own hand, after all.


Primaris Space Marines of the Ultramarines Chapter help spearhead the Indomitus Crusade

The newly reinstated Lord Commander of the Imperium decreed that those Chapters most devastated by the ongoing wars should be amongst the first to be reinforced with this new breed of transhuman warrior. Starting with the Ultramarines, but also deploying these new Space Marines to every other Chapter in need, Guilliman aimed to reinforce the Imperium's scattered defenders across the galaxy. It was not just as reinforcements to existing Chapters though. Guilliman also ordered the creation of a host of new Chapters, the so-called "Ultima Founding", composed entirely of Primaris Space Marines. The warriors of these new Chapters were created entirely using the new processes discovered by Archmagos Belisarius Cawl and established with all the necessary weapons, armour and equipment that they will need to conduct their defence of the Imperium.

These Chapters still trace their genetic lineage back to the gene-seed of the First Founding, and scions of all nine Loyalist Space Marine Legions emerged from the vaults beneath the Red Planet. They benefit from three additional gene-seed organs and larger size, but it still remains to be seen if Cawl was able to successfully stabilise any of the known genetic deviations or impart any additional resistance to the effects of Chaos. Many of these new Chapters have been assigned homeworlds on the edge of the Great Rift, the Imperium's new frontline in the war against Chaos, though some have inherited the empty fortress-monasteries of Chapters that had been lost to the attrition of constant war. Many of these worlds face a continuous battle against the daemons of the Warp, as well as an unpredictable mix of xenos raiders, pirates and invaders.

During the Indomitus Crusade, Cawl's own fleet joined the Primarch, headed by his freighter-hulk, Zar-Quaesitor, a mech-ark class ship that carried within its massive hull a vast number of Primaris Marines still in stasis hibernation.

As the Indomitus Crusade penetrated deeper into the galaxy during the early 42nd Millennium of the original Imperial Calendar, Archmagos Cawl kept his automaton workers on overdrive, risking meltdowns with their accelerated speeds. Locked deep in the labyrinthine holds of Zar-Quaesitor, thousands of Primaris Space Marines -- some comprising entirely new Chapters and others designated as reinforcements for existing ones -- were awakened out of stasis and made ready to join the fray.

On battle-scarred Rynn's World, the arrival of the Indomitus Crusade broke the daemonic legions of the Daemon Prince Rhaxor. After the fighting was done, the Crimson Fists marvelled at the return of Roboute Guilliman, but were even more grateful for the arrival of Primaris Space Marines bearing their own heraldry. Here were warriors whose genetic composition was closer to their own Primarch, Rogal Dorn, than had ever before existed. For his raw material, Cawl had selected warriors of Terra, and had taken them only a few generations after the original Imperial Fists had been created by the Emperor. Indeed, some had been held in stasis since the days of the Great Crusade; a few of the Primaris Space Marines could recall having seen Rogal Dorn himself.

Again and again the Crusaders watched the same tale unfold. When those of the Ultima Founding were brought before their Chapters, it was like a meeting of brothers separated at birth. Arriving at a time of great darkness and upheaval, the new transhuman warriors' strength was welcomed. Such unusual reunions were repeated on many Astartes worlds, including Chogoris, Ultramar and Baal, where the Crusade arrived even as the proud Sons of Sanguinius were making what they thought would be their last stand against the Tyranids of Hive Fleet Leviathan during what became known as the Devastation of Baal.

Despite cleaving a wide path through the darkness that beset the Imperium, the Indomitus Crusade began to break down. When the vast holds of the Zar-Quaesitor were at last emptied, Archmagos Cawl departed, for he had many more secret vaults to activate in order to complete the Ultima Founding. Once deployed, the new Primaris Chapters -- such as the Rift Stalkers or the Umbral Knights -- remained after the initial conflicts were won, seeking to consolidate the Crusade's gains; in many cases, they did this by establishing their own new Chapter planets. In this way, the Crusade not only freed worlds from the tyranny of the Dark Gods, but also strengthened their defences against further attacks that were sure to come.

Though they are a step removed from their brothers, the Primaris Space Marines still bear the gene-seed of their Primarchs, and some dissenting voices worry how this new type of warrior will react with the known genetic quirks and flaws of some of the more unusual Chapters, such as the Blood Angels and the Space Wolves. The Primaris Space Marines offer new hope to a besieged Imperium, but the future remains a dark and uncertain place...

The Unnumbered Sons


Codex Astartes-approved Heraldry for an Adeptus Astartes Chapter after the Ultima Founding of 999.M41

The Unnumbered Sons, officially known as the Unnumbered Sons of the Primarchs, and unofficially among themselves as the "Greyshields," were nine special formations of Primaris Space Marines created by Lord Commander of the Imperium Roboute Guilliman for service in the Indomitus Crusade. Active for over a standard century well into the 42nd Millennium, they were comprised of nine Space Marine Legion-sized armies of Primaris Space Marines, all drawn from the lineage of one of the 9 Primarchs who had led the Loyalist Space Marine Legions during the Horus Heresy. Approximately half of the Primaris Space Marines created by Belisarius Cawl during the Ultima Founding were formed into entirely new Chapters of the Adeptus Astartes, while the remaining half were placed within the Legion-sized armies of the Unnumbered Sons.

However, Guilliman forced these armies to fight using squads that contained Primaris Astartes from multiple different gene-lines to better forge cooperation between the different lineages. The Unnumbered Sons served as a reserve force for Guilliman during the Indomitus Crusade, their ranks slowly reduced by attrition and the need to replenish already-extant Chapters of the Adeptus Astartes with the new class of Primaris Space Marines. Other members of the Unnumbered Sons were eventually integrated into whole new Chapters comprised only of Primaris Astartes like their brethren. By the end of the Indomitus Crusade at the Battle of Raukos, over a standard century into the 42nd Millennium, the armies of the Unnumbered Sons had been reduced to approximately 20,000 Primaris Astartes, who were ultimately disbanded and divided up into a final group of new Primaris Chapters on the orders of Guilliman before his intervention in the Plague Wars of Ultramar.

Primaris Gene-Seed

"(They are...) a perversion of the Emperor's work. He may be a rotting corpse, but he created perfection in the Legiones Astartes. I cannot imagine for a moment that some arrogant Magos Biologis will have done anything but flaw that work beyond redemption."
— D'Sakh of the Alpha Legion Traitor Legion

Though they now stand a step above their standard Astartes brethren, all Primaris Space Marines were still created using the original gene-seed of their Primarchs, like all other members of the Adeptus Astartes. Some voices within the Imperium now worry how this new type of transhuman warrior will react to the many genetic quirks and flaws found in the gene-seed of some of the more unusual Chapters, particularly given the long history of fiascoes that have resulted from attempts to alter the Emperor's original work.

In the pursuit of his attempt to improve upon the original Space Marine template, Archmagos Belisarius Cawl collected samples of the genomes of all twenty of the original Primarchs, including those deemed Lost or Traitors, though Roboute Guilliman made clear to his overeager servant that Primaris Astartes were to be created only from the lines of those of his brothers who led the nine Loyalist Space Marine Legions.

It is known that in addition to the general advancements in their gene-seed, Primaris Space Marines possess three additional gene-seed implant organs compared to their standard brethren and that their gene-seed is far more genetically stable than that of their forerunners. Primaris Space Marine gene-seed has only a .001% chance of genetic deviancy from the original baseline with the passage of each generation, which makes it nearly immune to the severe genetic instability suffered by Chapters such as the Blood Angels and Space Wolves over the course of their existence.

Nearly every Space Marine created since the First Founding possesses nineteen specialised organs derived from this gene-seed. The Primaris Marines, however, are implanted with a further three additional organs. It was the Sangprimus Portum, a device containing potent genetic material harvested from the Primarchs, that allowed for this breakthrough. Entrusted to Cawl by Guilliman shortly after the Second Founding in the early 31st Millennium, this device resulted in a new breed of Adeptus Astartes that were deployed en masse in the Ultima Founding. Due to Cawl's interpretation of his orders and the millennia-spanning labour of his task -- during which Guilliman was injured and suspended in stasis -- the secrets of these new Primaris organs were not released until late in the 41st Millennium.

Primaris Organs

The Primaris Space Marines possess all of the nineteen gene-seed implant organs that have been gifted to their original Astartes brothers, as well as three more that only they possess, for a total of twenty-two. These new gifts of Belisarius Cawl's genius further enhance their transhuman status and ability to bring the Emperor's justice to a galaxy shrouded in darkness and despair. These additional implanted organs include:

  • Sinew Coils (The Steel Within) - The Primaris Space Marine's sinews are reinforced with durametallic coil-cables that can contract with incredible force, magnifying his strength as well as giving his body another layer of defence. A Primaris Space Marine can crush a man's skull in his hand, break Flak Armour to flinders, or even bite through a metal cable should the need arise.
  • Magnificat (The Amplifier) - A small, thumbnail-sized lobe that is inserted into the brain's cortex. The Magnificat secretes hormones that increase the body's growth functions whilst also intensifying the function of its other transhuman implants, especially those of the Biscopea and the Ossmodula. In truth, the Magnificat is but half of the true, dual-valve Immortis Gland (the so-called God-Maker) that the Emperor created for His Primarchs. However, Archmagos Cawl could only find materials and genetic blueprints to build the Dextrophic Lobe (the right half of the Immortis Gland), while plans for the Sintarius (the left half) that would complete the original super-organ had been wholly eradicated from Imperial records of the Primarch Project. Whether this was done by the Emperor's own hand or by some nefarious source, Cawl could not tell.
  • Belisarian Furnace (The Revitaliser) - This is a dormant organ that connects to both Astartes hearts. In times of extreme stress, or should the warrior's body undergo violent, damaging trauma, it expels great blurts of self-synthesized chemicals -- a hyper-cocktail that simulates the biological action of combat stimms while also aiding in the rapid regrowth of tissue, bone and muscle. The gland then falls dormant again, and takes some time to metabolically build itself up once more for the next usage.

Primaris Space Marine Organisation

Rank Structure

The Primaris Space Marines that form their own Chapters were established with a slightly variant Chapter hierarchy as a result of the changes made to the Codex Astartes by Roboute Guilliman, though many positions remained identical to those that had been long-established within the standard formations of the existing Adeptus Astartes.

Officers and Specialists

Primaris Captain
The Primaris Captain is a stoic, indomitable commander. He is as much a strategist and tactician as he is a warrior, possessing masteries in both ranged and close quarter combat. The Primaris Astartes Captain is identical in function to the standard Space Marine rank and commands a full company of 100 Primaris Space Marines.
Primaris Chaplain
40kPreviewJuly23 Chaplain8h
The Primaris Chaplain is the latest imposing iteration of a classic Space Marine hero. His Mark X Power Armour has been decorated with the symbols of his office, including a grim skull mask and Iron Halo. In one hand, he carries his signature Crozius Arcanum, while the other wields a high-calibre Absolvor Bolt Pistol. The Primaris Chaplain is a brutal melee combatant and can drive his fellow Primaris Astartes into a killing frenzy.
Primaris Apothecary
Primaris Apothecary
The Primaris Space Marine Apothecary serves as combat medic, physician and biomedical researcher; identical in function to standard Space Marine rank though better armed with an Absolvor Bolt Pistol and a Reductor Pistol to aid in the extraction of gene-seed from mortally wounded Astartes.
Primaris Librarian
Primaris Librarian
The Primaris Librarian blends the noble bearing of the Primaris Captain with a wealth of occult detail and baroque cybernetics indicative of a darker, more mysterious kind of warrior. He serves as both a combat psyker and Chapter lorekeeper and is identical in function to the standard Space Marine rank.
Primaris Lieutenant
Serves as a sub-company leader with two assigned per company of 100 Primaris Space Marines; this new rank has now been introduced to all Adeptus Astartes formations as Roboute Guilliman begins revisions to the Codex Astartes.
Primaris Ancient
The Ancient serves as a Standard Bearer for a company or full Chapter of Primaris Space Marines.

Squad Specialities

Squad Type
An Intercessor is the standard multirole heavy infantry of the Primaris Space Marines and is similar in combat function to a Tactical Squad of standard Astartes or a Legion Tactical Squad of ancient Astartes Legionaries.
An Inceptor is the standard Jump Pack-equipped heavy assault unit of the Primaris Space Marines who wear the Mark X Gravis variant of Mark X Power Armour; Inceptors are similar in combat function to an Assault Squad of standard Astartes.
Hellblasters are Primaris Space Marines who are intended to serve in the role of heavy fire support and are armed with Mark III Belisarius Pattern Plasma Incinerators. They serve a similar combat function as the ancient Legion Tactical Support Squads and to present-day Devastator Squads found among standard Astartes.
Reivers are a new type of Astartes combat specialist unique to formations of Primaris Space Marines who are tasked for close-combat stealth operations. Their Mark X Tacticus Power Armour has been modified to display a skull-faced helm, to possess enlarged left-side pauldrons and to run completely silently. Reivers are armed primarily to engage in close combat, and all make use of Combat Knives, Power Swords, heavy Bolt Pistols and handheld, deadly versions of the Bolt Rifle. Reivers can also stun enemy infantry with Shock Grenades or deploy deep behind hostile lines via Grapnel Launcher or Grav-Chutes.
The Aggressors are a new type of Astartes heavy combat support specialists unique to formations of Primaris Space Marines. They are tasked with heavy long-range fire support and have been outfitted with modified suits of Mark X Gravis Power Armour refitted to carry shoulder-mounted missile launchers that can be automatically reloaded from internal stores within their battle-plate. They also wield Flame Gauntlets that unleashing blazing streams of Promethium upon any foes that get in close.

See Also


Primaris Space Marine Forces
Command Primaris CaptainPrimaris LieutenantPrimaris Ancient
Specialists Primaris ApothecaryPrimaris LibrarianPrimaris Chaplain
Battleline Intercessor
Close Support InceptorReiver
Fire Support HellblasterAggressor
Combat Walkers and Vehicles AstraeusRedemptor DreadnoughtRepulsor
Aircraft Overlord



Warhammer 40,000 Introducing the Primaris Space Marine

Warhammer 40,000 Introducing the Primaris Space Marine

Warhammer 40,000 New Heroes for a Dark Imperium

Warhammer 40,000 New Heroes for a Dark Imperium