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"Let nothing dissuade your Quest for Knowledge. Let none slow your pursuit and acquisition of holy technology. Let no one stand between you and the procurement of that which is rightfully the Machine God's due."

—Thusdorius Knoch, Invictus Acquisitor

Mars, also known as the "Red Planet," is the first and greatest Forge World -- the "Forge World Principal" -- of the Imperium of Man. It is located in the Sol System of the Segmentum Solar, and produces vast numbers of weapons, vehicles and other advanced technology for the Imperium and its war efforts throughout the galaxy.

Mars is also the homeworld and headquarters of the Adeptus Mechanicus and a planet sacred to the faith of the Cult Mechanicus, which is one reason why travel to the Red Planet for Imperial personnel who are not members of the Mechanicus and share its peculiar faith is restricted.

The Red Planet is the birthplace of the Cult Mechanicus, and is considered the holiest of all celestial orbs in the galaxy to the adherents of that faith. So vaunted is Mars that across the stars a hundred worlds have been terraformed and settled in exactly the same manner.

Millennia of incessant construction have turned Mars into a smog-choked hellscape. The surface is covered with massive forge complexes, sprawling refineries, towering monuments to the glory of the machine and weapons shops that scrape the skies. The massive orbital conglomeration of thousands of drydocks and other starship manufacturing facilities in a geosynchronous orbit that turn above the Martian equator are known collectively as the Ring of Iron.

It was the shipyards of the Ring of Iron that constructed the vast exploratory and Expeditionary Fleets of the Great Crusade in the late 30th Millennium and even today produce the majority of the Imperial Navy's capital ships. Spacecraft are constructed within the Ring's extensive orbital factories, and many of the ships of the Battlefleet Solar are based in its huge floating docks. The moon Deimos is absent from Mars' orbit, seconded to the Grey Knights of Titan in aeons long past.

It is possible that Mars is also the world where the ancient and terrible C'tan known as the Void Dragon has chosen to slumber the eons away.


"Sing the song of the Machine God.
- None may stay our march.
Let he merciless logic of the Machine God invest thee.
- None may stay our march.
Praise and glory be to the Machine God.
- None may stay our march.

— Translation of binaric static chorus Litany of Praise
Forge Worlds Segmentum Solar

Adeptus Mechanicus stellar cartographic map depicting the Forge Worlds of the Segmentum Solar, including Mars, home of the Cult Mechanicus.

Mars is the twin planet of Terra, and one of many long-inhabited Human colony worlds located near the Cradle of Humanity. It is the homeworld and primary power centre of the Adeptus Mechanicus, the ancient and byzantine Tech-priests of the Machine God, and the heart of their galaxy-spanning monopoly on Human science and technology.

Following the Unification Wars in which the Emperor of Mankind defeated the techno-barbarians of Terra and reunited Humanity's homeworld under a single government, He concluded the Treaty of Mars (known as the Treaty of Olympus Mons within the Mechanicus) with the Cult Mechanicus to unify both Terra and Mars under the umbrella of the newborn Imperium of Man in the late 30th Millennium.

The ancient Mechanicum government of Mars recognised the Emperor as the Omnissiah, the Machine God incarnate, and swore to lend their technology, the mighty war machines of their Titan Legions and all of their production facilities to the purpose of His Great Crusade to reunite all the scattered worlds of Mankind beneath the rule of the Imperium.

In return, the Emperor promised the Mechanicum that it could maintain its political autonomy on Mars and all of its other Forge Worlds across the galaxy and that it would remain immune from adherence to the atheistic doctrine of the Imperial Truth. This ensured that the adepts of the Mechanicum could still maintain their faith in the Machine God.

Therefore, Mars is just as important to the Imperium's survival as Terra itself, a reality reflected in the emblem of the two-headed Imperial Aquila, one head for Terra, the other for the Red Planet.

Terraforming of Mars c

Ancient Mechanicum Historical Map of Mars, circa M30; the extensive terraforming that had transformed Mars into a habitable world during the Age of Technology was slowly undone by the rampant industry of war during the Age of Strife.

In ancient times, Mars had a fully terraformed atmosphere and ecosystems very similar to that of ancient Terra during the Age of Technology, but the constant warfare of the Age of Strife and the later rapid industrialisation of the surface after the Mechanicum secured total control over the world destroyed Mars' manufactured oxygen-nitrogen atmosphere and restored the Red Planet's surface to its primordial desert state, absent surface water and breathable oxygen. The only inhabitable regions of the planet now are the Adeptus Mechanicus' hive cities -- called "forge cities" or just "forges."

More than any other Human-settled world, Mars possesses huge repositories of technical knowledge. Its immense libraries and databanks are highly eclectic and disorganised; one delving for secrets may find a crystal storage device containing vital genetor-level data tucked inside a scrollprint for militarised locomotives.

Mars c

Adeptus Mechanicus Historical Map of Mars, circa M35; as forge temples and manufactoria sprawls spread further over the millennia, the air became toxic, the seas slowly dried up and the deserts turned barren once more.

The planet itself is a wilderness of polluted ochre desert broken by metropolises the size of tectonic plates. Here the rockcrete spires, marble arches and flying buttresses of a standard Imperial world are joined by corroded steel, iron ventilation chimneys and shining glass pipes.

Extensive travel tubes pass above crackling tesla coils that power construction sites and ancient industrial wastes alike. Shining new buildings braced with riggings of steel contrast with shattered condensation traps and the ruins of millennia-old wars. The older districts are dotted with broken plasteel slabs and twisted girders, the occasional solitary tower pointing purposelessly toward the Martian sky.

Mars is strictly stratified in its social order. The Red Planet is ruled over by the Adeptus Mechanicus' fabricator-general, and the Mechanicus possesses almost every known piece of Standard Template Construct (STC) technology or designs currently in Imperial hands. This is ostensibly so that the Mechanicus can construct better and more durable vehicles and technology for the Imperium, although it is fairly clear that the Mechanicus is simply hoarding them.

The lowest social level consists of the Martian citizens, mainly unaugmented Human populations who labour en masse at simple tasks such as sorting isotope scrap, tending hydroponics, breaking ore, stoking forges and so on.

Most citizens aspire to gain status within Mars' theocratic society by joining the Skitarii Legions. In the process, they will receive their first battle-grade bionics and perhaps a way of later entering the full priesthood of the Machine God.

Lesser citizens may sport tattoos and piercings suggestive of such bionics, but dress in common work clothes -- filthy coveralls, rad-tabards or cabled environ-suits. Regardless of station, Martians have a tendency to be burly, saturnine and shaven-headed, usually with a temper to match their dour aspect.

All sport electoos -- subcutaneous cyberware that ranges from code-patches through which personal data is monitored to thick veins of electric cabling. Through these electoo circuits can the glory of the Omnissiah be channelled. In times of great strife, the masters of Mars' populace can use these interfaces to turn even the most gormless hab-worker into a dauntless warrior of the Machine God.

It is also rumoured that the most powerful of the C'tan, the Void Dragon, considered by some savants to be akin to the ancient entity known as the "Dragon of Mars," sleeps somewhere beneath the surface of the Red Planet, in the Noctis Labyrinth.

The presence of this entity may be the reason why Necron starships briefly landed on the Red Planet in 998.M41 for unknown reasons. Should the Void Dragon awake, the very heart of the Imperium will tremble.

Notable Campaigns and Events

  • Mars Expands (ca. M25-M30) - Mars overcomes strife and disaster to unite beneath the Cult Mechanicus and its ruling Mechanicum government and planetary parliament. As lulls between the waves of Warp Storms during the Age of Strife allow, the fleets of Mars travel outwards, raiding for technology and establishing new colonies of Tech-priests. With a few exceptions, such travels remain limited in scope and stay within the confines of what will later become known as the Segmentum Solar.
  • Treaty of Mars (ca. 798.M30) - The Emperor, fresh from uniting the tribes of Terra, arrives on Mars. Many of the Tech-priests of the ruling Mechanicum declare Him to be the Omnissiah, and so the Emperor forges an alliance between Terra and its old rival Mars. It is the adepts of the Cult Mechanicus that equip the Emperor's Space Marine Legions for the Great Crusade. In recognition of the fact that to achieve His galactic plans, the Emperor needs the technological and scientific aid of the Mechanicum, Mars becomes an ally to Terra rather than her subject, which is cemented by the signing of the Treaty of Olympus Mons, known as the Treaty of Mars on Terra. Of the countless worlds that the Imperium soon claims, only Forge Worlds dedicated to the Cult Mechanicus are esteemed in such a way.
  • Great Expansion (798.M30-004.M31) - The Emperor leads the massive Great Crusade outwards from Terra, with the purpose of reuniting the hundreds of thousands of lost Human-settled worlds scattered across the galaxy. At the fore are the Space Marine Legions, supported by the growing Imperial Army. All are equipped by the manufactoria and orbital fleet yards of Mars. No less important are the Skitarii Legions, the Legio Cybernetica, the Legio Titanicus, and the Imperial Knights that join the expedition. Planet after planet is reconquered and offered the same choice -- bow before the Emperor of Terra or be destroyed. On and on the expeditionary fleets push outwards. The Tech-priests often refer to this time as the "Great Expansion," for hundreds of Forge Worlds and Knight Worlds are rediscovered during this period alone.
  • Horus Heresy (005-014.M31) - Like all of the branches of the Imperium, the Mechanicum finds itself rife with corruption during the epic civil war known as the Horus Heresy. Many Forge Worlds and Knight Worlds turn from the Emperor. Indeed, the Fabricator-General of Mars, Kelbor-Hal himself declares his allegiance to Horus, and so begins the Schism of Mars, a bitterly-fought campaign that mirrors those taking place across the galaxy. Skitarii Legions square off against each other while Titan duels Titan. Those of the Cult Mechanicus that turn to the Chaos Gods are forever after known as the Dark Mechanicum. They are hated and feared in equal measure, for they dare to fuse Daemons with the Machine Spirits of their war engines, creating twisted things that mock the Machine God and his true laws of order and reason.
  • Prophet of Cogs (Unknown Date.M34) - The long-time cultural rivalry between those Tech-priests who dwell in the north of Mars and those of the Martian south flares into open war. As the conflict grinds on, both sides are assailed by the feral packs of malfunctioning servitors and burnt-out war machines that still haunt the desert wastes, many dating to the Age of Strife. The war reaches a gory conclusion when the self-proclaimed Prophet of Cogs broadcasts a control-chorus that binds millions of long-abandoned machines to his cause. Appalled by the half-living cyberghouls he sets on his foes, both the Martian north and south unite to drive him from the Red Planet. Rumours persist that he still haunts the Alpha Centauri System.
  • Moirae Schism (ca. Early M35) - During the secession of the Segmentum Pacificus in the Nova Terra Interregnum, the rebel Forge World Moirae is destroyed by retaliatory Exterminatus, but not before the Moirae Schism has split the Adeptus Mechanicus in two. The ensuing conflict draws Titan Legions and even those Space Marine Chapters affiliated with the Adeptus Mechanicus into the turmoil. The schism takes a heavy toll on the Adeptus Astartes, resulting in the destruction of dozens of companies and the excommunication of several Iron Hands clans. It takes over two millennia of desperate warfare before the Moirate doctrines are considered fully purged.
  • Occlusiad War (550-560.M37) - The northwestern fringe of the galaxy is ravaged during the devastating Occlusiad War by the Apostles of the Blind King, rogue Tech-priests who view Humanity's existence as an affront to the Machine God. War rages for a solar decade, but the tide turns when the palace-warship of the Blind King is found hidden in a fold of Warpspace. The Blind King is slain and the Apostles overcome -- not least due to the efforts of Mars itself and the founding of the heroic Dark Hunters Chapter.
  • War of the Golden Cog (Unknown Date.M39) - The fabricator-general of Mars claims ownership of the riches of the Fortress of the Soulless, lair of the Culexus Temple. A disastrous civil war between Mars and Terra is averted by a sniper's bullet, but the artefact known as the Golden Cog is left in Skitarii hands.
  • Necrons Invade Mars (998.M41) Five Necron Shroud-class Light Cruisers entered the Sol System undetected by the Titan monitoring station. A commercial system freighter detected them. System defence ships were deployed on intercepting trajectories, but any that managed to enter range were destroyed. The Defence Monitor Javelin engaged the Shroud-class Light Cruisers near Mars, but the well-shielded vessel was destroyed by the xenos. The Necron squadron was able to avoid an outer minefield and and speed past the Deimos chain of orbital weapons platforms. The Phobos line damaged one, which was then scuttled by the other Necron vessels. The remaining Shroud-class cruisers attacked the subterranean mines of Mars for unknown reasons before Starhawk bombers launched by Imperial Navy vessels located and finally destroyed them. A perdita exclusion zone, enforced by an entire Skitarii Legion, was established around the Noctis Labyrinthus following this incident.
  • Indomitus Crusade (ca. 999.M41 - Present) - Following the destruction of Cadia, Warp storms of a magnitude not seen since the Age of Strife wrack the galaxy. Every Forge World is cut off from its Explorator fleets and, for a time, from each other. All suffer invasions and raids as emboldened xenos and Chaos forces test them, probing for weaknesses, eager to destroy the bastions of Mankind's empire. No fewer than seven Forge Worlds are destroyed altogether and several more remain missing, buried beneath fierce and impenetrable storms. The initial Blackness that blanketed the galaxy after the Great Rift was torn open finally lifts. In the aftermath of the Noctis Aeterna, many Imperial Crusades are launched. Although there were several successful campaigns, none could claim more triumphs than the Indomitus Crusade. From Terra, Roboute Guilliman mustered a coalition. In addition to Archmagos Dominus Belisarius Cawl, Mars sent many Skitarii Legions, maniples of the Legio Cybernetica and several lances of Knights from House Taranis. Over a dozen other Forge Worlds send supporting fleets as the expedition crosses the galaxy, and many Knight Worlds prove eager to join -- none more so than the vengeful House Krast. The crusade's many victories bring a glimmer of hope to the darkened Imperium. However, once the primary fleet of the crusade returns to aid Ultramar during the Plague Wars, the remaining forces splinter, the campaign losing impetus as some Mechanicus factions return to protect their own homeworlds.
  • Adeptus Mechanicus Unleashed (Unknown Date.M42) - With the Imperium reeling from the disastrous effects of the birth of the Great Rift, Mars commands all Forge Worlds to ramp up production to unprecedented levels. They churn through raw materials and servitors as never before, and vast armadas are launched to strip entire star systems of resources. The forges must be fed at impossible rates in order to supply the endless war materiel required.
  • Rust Fields War Begins (Unknown Date.M42) - To fuel their factories, a coalition of Forge Worlds led by Mars and Graia sends mining fleets to exploit the vast belt of asteroids known as the Rust Fields. Although its interior has never been explored, its exterior is incredibly rich in all manner of metals, minerals and promethium seas -- a tumbling horizon of asteroids that stretches across three sectors. Soon after operations are begun, however, it is discovered that Greenskin clans rule the interior of the Rust Fields. So begins a great war that draws in untold numbers of additional Imperial forces as the Adeptus Mechanicus fights to retain its foothold.
  • Bane of the Forge Worlds (Unknown Date.M42) - Although there are many theories, none understands the reason for the Necron attacks upon Forge World territories as well as Archmagos Belisarius Cawl. Both sides are seeking deposits of the strange material from which the Cadian Pylons were fashioned, and many Adeptus Mechanicus strongholds have been erected upon sites containing this precious resource. Cawl sends his own agents -- armies of Mars and House Taranis -- across the stars in an effort to combat the growing danger, and hundreds of battles are fought as more and more Forge Worlds are drawn into the conflict to aid their beleaguered brethren. Even those Tech-priests that begin to understand the reality of the dire situation are loath to call upon their Imperial allies for fear of being branded Hereteks.

Planetary Data

Mars Tharsis Map

Map of Mars' Tharsis region at the time of the Horus Heresy in the early 31st Millennium

  • Mass: 6.42 x 1023 kg
  • Diameter: 6787 km
  • Mean density: 3940 kg/m3
  • Escape velocity: 5000 m/sec
  • Mean distance from Sun: 1.524 AU
  • Rotation period: 1.026 solar days
  • Revolution period: 686.98 solar days
  • Obliquity: 25°
  • Orbit (inclination degree): 1.85°
  • Orbit eccentricity: .0.093°
  • Max. surface temperature: 310° K
  • Min. surface temperature: 150° K
  • Visual geometric albedo: 0.15
  • Highest point on surface: Olympus Mons
  • Atmospheric components: 95% carbon dioxide, 3% nitrogen, 1.6% argon
  • Surface materials: basaltic rock and altered materials


Mars Red Planet

Key locations of Mars, the first Forge World

Map Key

  1. Glaivid Hive
  1. Oxygos Hive
  1. Olympus Undae Hive
  1. Hyperboreae Undae
  1. Collegia Titanica
  1. Mare Chronius
  1. Tantalus Hive
  1. Milancovic Fusion Reactor
  1. Arcadia solar collector fields
  1. Omnid Apertura
  1. The Grand Temple of the Omnissiah
  1. Mareotis Forge Temple
  1. Acheron Fosse Forge Temples
  1. Arsia Mons
  1. Fabricator-General Forge Temple
  1. Temple of the Frictionless Piston
  1. Temple of All Knowledge
  1. Deep core mines
  1. Ascraeus Mons
  1. Dodecai Elevatus Prime
  1. Dodecai Elevatus Secundus
  1. Navis Imperialis assembly yards
  1. Esperanos Space Port
  1. Deus Manus Space Port
  1. Ipluvien Maximal
  1. Fortress temple of Knight House Taranis
  1. Pavonis Mons
  1. Navis Imperialis Mars Docks
  1. Xanthos
  1. Fortress temple of Legio Tempestus
  1. Noctis Labyrinthus (Anathemor)
  1. Haunted Dunes of Solis Planum
  1. Candor Casma
  1. Varnalia
  1. Mondus Terrawatt II complex
  1. Lybia Montes forge temples
  1. Lethe Zone
  1. Antionradi Forge Temple
  1. Mondus Gamma Forge Temple
  1. Mechavitae Forge Temple
  1. The Rust Wastes
  1. Cthonia
  1. Autonoct Deserts
  1. Sornia
  1. Nilosyrtis Hive
  1. Sydonian Tetrahedra
  1. Protoservitor Cradle
  1. Sydonian Mistsea
  1. Sydonian Mask
  1. Acidalia Planitia
  1. Sea of Iron Curses
  1. Vastitas Borealis

Notable Locationse

  • High Altar of Technology - Within the Temple of All Knowledge is the High Altar of Technology -- a vast database containing the knowledge of the Tech-priests. Even today every new discovery is dedicated to this altar. Every temple on Mars and throughout the other Forge Worlds is connected to the High Altar by means of a living Transmat link, a psychic Servitor whose mind co-joins all altars of the Cult Mechanicus into one holy machine entity.
  • Librarius Omnis - The Librarius Omnis is a vast subterranean, continent-spanning repository of knowledge located in the labyrinthine catacombs of Mars. Over the millennia, it has been the subject of several Techno-archaeologist expeditions. It was here, at the dawn of the Imperium, that the legendary Techno-Archaelogist Arkhan Land led an expedition with the intention of finding an intact, complete and still-functioning STC database. Though he was unsuccessful in this endeavour, he did make two other discoveries which revolutionised Imperial technical thinking for millennia to come -- a near complete dataslab image of STC information on what would come to be known as a Land Raider, and information on rare anti-gravitic plates, and theories on their uses, which eventually led to the construction of the first "Land Speeder."
  • Libarium Omnissiah - The Librarium Omnissiah is a large repository of knowledge said to contain large, mile-long logi-stacks which contains records of thousands of mysteries of the universe. It is said to rival even the archive-catacombs of the Adeptus Terra.
  • Mondus Occulam - Mondus Occulam was a powerful Forge Temple located in the Tharsis region of Mars. At the dawn of the 31st Millennium, it was one of the largest and most productive Forge Temples on Mars, surpassed by only Olympus Mons in size. Like many forges at the time, it was geared for war production -- exclusively manufacturing arms, equipment and Power Armour for the Legiones Astartes spread across the galaxy during the Great Crusade. As a result of their size and productivity output, Forge Master Zagreus Kane was made Fabricator Locum, the second highest-ranking individual of the Mechanicum, responsible for assisting the Fabricator-General with the governance of Mars. This particular forge was also responsible for the training of Space Marine Legionaries to become Techmarines. Only Mondus Gamma forge, under the mastery of Lukas Chrom, could replicate the quality of training offered by Mondus Occulam, but they could not match Mondus Occulam for the sheer quantity of well-trained Techmarines coming out of their forge. Following the outbreak of hostilities between the Dark Mechanicum and those Tech-priests still loyal to the Throneworld during the Schism of Mars, Mondus Occulam was one of the few forges that escaped total collapse when Chaotic scrapcode was unleashed throughout Mars' communication networks. Elements of the Imperial Fists, under the commander of First Captain Sigismund, managed to make planetfall and secure the forge's armour and weapons supplies. Despite the protestations of Fabricator Locum Kane to save his forge, Sigismund ordered the evacuation of Mondus Occulam when over sixty Traitor Titans launched an overwhelming assault on the forge.
  • Noctis Labyrinth - The Noctis Labyrinth is a region of Mars that lies between the Valles Marineris and the Tharsis Uplands. In Low Gothic, the name translates as "Labyrinth of the Night." It is here, deep beneath the Noctis Labyrinthus, that the fearful entity, known only as the Dragon of Mars in Mechanicus legend, sleeps for eternity. This being may be the C'tan known as Mag'ladroth the Void Dragon, who was imprisoned there by the man who became the Emperor of Mankind millennia prior to the dawning of the Age of Strife and is watched over by a single guardian, a Terran girl named Dalia Cythera, who has guarded it since the Schism of Mars during the Horus Heresy. It would be another 10,000 standard years before a new guardian would be drawn to the Noctis Labyrinth to take Dalia's place.
  • Olympus Mons - Known also as the "Grand Mountain" to the Titan Legions of Mars, Olympus Mons is the largest mountain on the Red Planet and is the site of the largest and most productive Forge Temple. This is the seat of the ruling Fabricator-General of Mars. It is also here that the largest structure on Mars -- the all-important Temple of All Knowledge -- lies within the massive city.
  • Ring of Iron - The Ring of Iron is the name given to the massive, ring-like orbital constructions that turn above the Martian equator. Spacecraft and other large starfaring constructs are constructed within the Ring's extensive orbital factories, and many of the starships of the Battlefleet Solar are based in its huge floating docks.
  • Temple of All Knowledge - The Temple of All Knowledge is the holiest place on all of Mars. Within the temple's plasteel shell, shining pistons hold the vaulted roof almost a Terran mile above. The shafts of each prism are so constructed that they move to raise and lower the roof, altering its acoustic properties to accentuate the hymns of praise sung to the Machine God. Within is the High Altar of Technology, the vast database containing all knowledge of the Tech-priests of Mars. Despite the massive Warp rift known as the Great Rift dividing the Imperium in two since 999.M41, the Temple of High Knowledge still receives messages daily which are down-loaded into the High Altar -- fleeting reports from the other Forge Worlds across the galaxy, data from recovered machines, confirmations of new discoveries, or desperate pleas for help.
  • Tharsis - Tharsis is the region of Mars that surrounds the capital at Olympus Mons. During the early years of the 31st Millennium, it was one of the most productive and abundant on all of Mars and was home to a number of powerful Forge Temples. By the late 41st Millennium, holding mastery of a Tharsis-based forge was still considered a valuable position for a member of the Cult Mechanicus.
  • Vaults of Moravec - The Vaults of Moravec were a depository of forbidden knowledge and techno-arcana founded by Primus Moravec of the Brotherhood of Singularitarianism, who sought to hasten the creation of a technological singularity which would create an artificial general intelligence greater than Human intelligence. Located on the Mechanicum's holy world of Mars in the Segmentum Solar, it was hidden in a sealed vault inside a maze of old tunnels and chambers nearly a kilometre deep beneath Olympus Mons -- the mighty forge of Fabricator-General Kelbor-Hal. The Vaults of Moravec had been deliberately kept locked by the Emperor of Mankind who correctly judged the knowledge it contained as too dangerous to be known publicly. When the Warmaster Horus Lupercal began to plot his rebellion against his father, he promised Kelbor-Hal to lift the Emperor's ban on the forbidden knowledge stored there, thus swaying this powerful figure to his service. The opening of the Vaults of Moravec would spark the civil war inside the Mechanicum that would become known as the Schism of Mars and mark the true birth of the Dark Mechanicum.

Forces of Mars

Legiones Skitarii

"Broadcast the psalms of war to drive the macroclades to triumph."

— Excerpt from Canticles of War Doctrine Alpha
Skitarii Cohort1

A Skitarii Cohort of Mars

Mars' Skitarii Legion is the most glorious of all its cybernetic kind. Its warriors consider it a great privilege to wear the ancient heraldry of the Red Planet, and are fiercely defensive of their Forge World despite its unchallenged position of power in the Cult Mechanicus. Perhaps because of the acquisitive nature of their masters, the red, silver and black of Mars' Skitarii War Cohorts is a common sight in each segmentum of the Imperium.

Each Skitarius is but a single cog in a war machine that spans the entire Imperium. Controlled by the neurosync imperatives of their Tech-priest masters, the Skitarii are organised into regiments called "War Cohorts" capable of overcoming any foe. They work in glorious concert, every footstep or twitch of the trigger finger optimised to further the cause of the sacred Cult Mechanicus.

Mars Skitarii

A Martian Skitarii warrior

The original maniples that crossed the desert reaches of Mars on foot were armed only with Galvanic Rifles. They escorted their masters from north to south across an equatorial belt infested with cannibal servitors and rogue machine intelligences. As the standard centuries marched past, these escorts were refined over and over again until they evolved into the Battle Maniples of the 41st Millennium. Many variants have been codified, from the Maniples Automata of the Legio Cybernetica to the teeming Auxilia Ordinatus, but the core fighting formation remains the War Cohort.

Like its fellow Forge Worlds, Mars' Skitarii Legion is divided into a number of "macroclades," which are in turn broken down into smaller units called "cohorts" and "maniples." The vast majority of Skitarii War Cohorts are not borne into battle by armoured machines or aircraft, but simply stride to the front line without stopping, even should they have to start the journey solar months in advance of their allies. They will wade through poisonous swamps and bubbling lakes of tar to arrive at the front line on schedule, rank upon rank of Skitarii marching around chains of Onager Dunecrawlers in imitation of Mars' nomadic caravanserais. Their tireless pace echoes the constancy of their dutiful souls -- it is said that a Skitarius would rather walk themself to death than disobey a direct imperative.

Forge World Dogma

Glory to the Omnissiah

In all the Cult Mechanicus, there are no Forge Worlds more holy or more blessed than Mars. The favour of the Machine God can be seen in the powerful optimisation granted by every static-ridden psalm incanted by his most faithful followers.

Forces of Mars Appearance

Mars Iconography

Mars Forge World

The official Imperial stamp of the Forge World of Mars, used on all of its manufactured goods.

The holy cog-and-skull of Mars, the Cog Mechanicum, graces many Martian Skitarii warriors and vehicles, a reminder that all must play their part in the greater war machine of the Adeptus Mechanicus.

Mars Forge World Colours

Like other Forge Worlds, Mars maintains its own Skitarii forces to protect its interests, annihilate the enemies of the Tech-priests, and fight at the vanguard of the Quest for Knowledge. The Skitarii cohorts of Mars wrap themselves in flapping crimson robes which are reminiscent of the rolling toxic deserts of their homeworld.

Long ago, this was doubtless a means of camouflage among the ruddy landscapes of the Martian wilderness, but it has since become a symbol of the might of the Adeptus Mechanicus across the length and breadth of the Imperium. Adorning the hems of these crimson robes and the sculpted chest plates of the Skitarii are ancient symbols and icons, each one heavy with meaning sacred to the Cult of the Machine God.

The white toothed iconography which rings the hoods, sleeves and hems of their robes is reminiscent of the teeth of a cog, a symbol of great significance to the Tech-priests of the Cult Mechanicus. This pledges their allegiance to the Machine God, and is thus important to all his servants.

Mars Skitarii Alpha

A Mars Skitarii Alpha proudly displaying the colours of his Forge World.

Skitarii Vanguard and Skitarii Rangers alike wear combat robes emblazoned with the icon of their Forge World. Skitarii infantry usually have their squad number emblazoned upon the hem of their robes for easy identification, while Sicarian Princeps and Skitarii Alphas bear their unit's maniple sigil, and sometimes a skull marking their status as overseers. Lower-ranked Sicarians often bear no markings other than the colours of Mars.

Some specialist units, such as Sicarian Ruststalkers and Infiltrators, may wear a number on their helm or chestplate. The armour plates of Skitarii vehicles are the same hue as those worn by the Legion's Sicarians.

The Tech-priests Dominus of Mars may wear variants of their Forge World's heraldry, but always incorporate the dull silver of industrial sprawl, the matte black of scorched carbon residue, and the deep red of the Martian sunrise.

The Electro-priests of Mars wear robes the deep red of their home planet, in keeping with the traditions of the Cult Mechanicus. Congregations may be distinguished by different decorative metals or markings upon their robes.

Each Kastelan-class Robot is a totem of the Omnissiah's might and so is accorded a unique recognition symbol, commonly borne upon the knee and shoulder. Maniple sigils may also be applied to robots and the armour of their attendant Legio Cybernetica Datasmiths.



  • Battlefleet Gothic - 2002 Annual, pp. 10-11
  • Codex: Adeptus Mechanicus (8th Edition), pp. 6, 8-10, 12, 14-23, 29-35, 39, 41, 45, 48-49, 52, 54, 61, 72, 74, 82, 95, 98-99, 100-101
  • Codex: Adeptus Mechanicus - Skitarii (7th Edition), pp. 22-27, 55-64
  • Codex: Adeptus Mechanicus - Cult Mechanicus (7th Edition), pp. 6, 8-9, 25-26, 36-38, 52, 60-66, 68, 70
  • Codex Imperialis (2nd Edition), pg. 42
  • Codex: Necrons (3rd Edition), pg. 11
  • Cult Mechanicus Painting Guide - Crusaders of the Machine God (Painting Guide), pp. 4-17
  • Heralds of the Siege (Anthology) edited by Nick Kyme and Laurie Goulding, "Myriad" by Rob Sanders
  • Horus Heresy: Collected Visions, pg. 369
  • Imperial Armour Volume One - Imperial Guard & Imperial Navy, pp. 81, 160
  • Skitarii Painting Guide - Legions of the Omnissiah (2015), pp. 3-19
  • The Horus Heresy - Book One: Betrayal (Forge World Series) by Alan Bligh, pg. 16
  • Titan Legions (2nd Edition), pg. 10-13
  • Warhammer 40,000: Rulebook (8th Edition), pp. 25, 27, 33, 40-42, 48, 50, 60, 73-74, 277-279
  • Warhammer 40,000: Rulebook (5th Edition)
  • White Dwarf 246 (UK), "Steel Chariots - The Space Marine Land Raider"
  • White Dwarf 178 (UK), "The Titan Legions," by Rick Priestley
  • Mechanicum (Novel) by Graham McNeill
  • The Hunt for Vulkan (Book Seven) (Novel) by David Annandale
  • The Last Wall (Novel) by David Annandale, Ch. 9


Raven Rock Videos
Warhammer 40,000 Overview Grim Dark Lore Teaser TrailerPart 1: ExodusPart 2: The Golden AgePart 3: Old NightPart 4: Rise of the EmperorPart 5: UnityPart 6: Lords of MarsPart 7: The Machine GodPart 8: ImperiumPart 9: The Fall of the AeldariPart 10: Gods and DaemonsPart 11: Great Crusade BeginsPart 12: The Son of StrifePart 13: Lost and FoundPart 14: A Thousand SonsPart 15: Bearer of the WordPart 16: The Perfect CityPart 17: Triumph at UllanorPart 18: Return to TerraPart 19: Council of NikaeaPart 20: Serpent in the GardenPart 21: Horus FallingPart 22: TraitorsPart 23: Folly of MagnusPart 24: Dark GambitsPart 25: HeresyPart 26: Flight of the EisensteinPart 27: MassacrePart 28: Requiem for a DreamPart 29: The SiegePart 30: Imperium InvictusPart 31: The Age of RebirthPart 32: The Rise of AbaddonPart 33: Saints and BeastsPart 34: InterregnumPart 35: Age of ApostasyPart 36: The Great DevourerPart 37: The Time of EndingPart 38: The 13th Black CrusadePart 39: ResurrectionPart 40: Indomitus