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Medusa, formally Medusa IV, is the Chapter homeworld of the Iron Hands Chapter of Space Marines and of their lost Primarch, Ferrus Manus. The Feral World of Medusa is a harsh realm of perpetual gloom, situated precariously close to the Eye of Terror in the Segmentum Obscurus.

The sun almost never breaks through the dark and polluted sky, as it constantly churns over a land of frozen mountain ranges, interspersed with volcanoes and boiling hot geysers. The landscape is under constant flux, the shifting of tectonic plates forming new mountains and seas, and destroying them as quickly as they are created.


The Medusan Inheritance

A cold, barely life-sustaining planet several times the size of Terra located in the outer darkness of the Segmentum Obscurus, Medusa is the fourth world orbiting a supergiant star known in the ancient Terran astrocartographic charts as Sthenelus.

In the lost days of human might during the High Age of Technology, the ancient lore of the Mechanicum holds that Medusa was a world deemed of great importance, its depths mined for rare core-strata deposits by vast, tireless robotic engines and its riches guarded jealously from rival species by sleepless guardians. So it was that when the shadow of the Age of Strife fell and all was given over to bloodshed and anarchy, Medusa, unlike so many other lost domains of Mankind, was not forgotten by Mars nor on Old Earth but remained a legend of glory and wealth.

The exact origins of the human presence on Medusa is uncertain, and genetic evidence reveals that it is most likely to have been the result of several different survivor groups, some perhaps dating back to the colonists of the Dark Age of Technology, others almost certainly the stranded remnants of star-wrecks and pre-Navigator sleeper ships launched by the Mechanicum during the Age of Strife to find this fabled world.

These antagonistic survivor-waves of the population, confronted by the near-unlivable surface conditions created by the planet's harsh climate, violently unstable geology and lack of native flora and fauna, devolved into techno-barbaric savages. Further forced into a nomadic existence by a constantly shifting landscape where mountain ranges and seas could be forged or unmade in a season, the Medusans retained by rote a degenerate superstition-ridden faith based around the dim memories of the Cult Mechanicus, a vastly uneven trove of weapon-crafting, cybernetic and mechanical lore, but lost all semblance of civilisation beyond that of the basest hunter-gatherer.

They formed into mobile, semi-tribal clans, the largest of which were centred on massive fortified land-crawlers (based in part on ancient STC designs for mining and harvesting engines), from which raiding and foraging parties set out to claim meagre resources and make ceaseless war on the other clans. They were a savage and unforgiving people; slavers and killers to whom the battle to survive was an unrelenting, bloody struggle in which only the strongest prospered.

As the Imperial Expeditionary fleets of the Great Crusade broke out of the Segmentum Solar in the late 30th Millennium, following the Warp-tides to the edges of the uttermost unknown, famed Medusa was high upon the Crusade's list of targeted goals, although its exact position was now uncertain. When a Mechanicum Warp-runner, more than a standard year out and alone in the darkness ahead of the main fleets first broke from the Empyrean into the Sthenelus star system and rediscovered Medusa, the sight that greeted them was both unexpected and bleak.

The whole range of the system's inner sphere was littered with the debris of shattered voidships, fogs of silicate dust, dead hulks and fractured planetoids, all as cold and silent as the grave. Around Medusa itself, the legendary Telstarax -- the colossal planet-circling orbital ring-station which had girthed Medusa in the Dark Age of Technology to plunder its riches and carry them aloft into space on immense tether-conveyors -- was a tortured ruin, much of it having fallen back to the planet with no doubt catastrophic force. As the Warp-runner closed with the planet, it found itself beset by many dangers, from sudden ionic squalls to erratically functioning mines and autonomous weapons systems -- ancient, but still deadly -- hiding in the debris fields. Wounded, it still went on, lured by the myth of Medusa.

Reaching close orbit, the Warp-runner scanned through the thick and shrouding atmosphere, casting the hard electromagnetic glare of its Auspex on the planet below. It found a world almost lifeless and shuddering with dangerous and near-constant tectonic instability. From the Warp-runner's high vantage point, it could see the worm-coring of played-out mine workings deep beneath the sheet ice and tundra, Medusa's cold ground further riven with immense scars and impact craters, although whether from sky-fallen debris from the Telstarax ring or some ancient orbital bombardment, it could not ascertain.

It also heard signals; the ghosts of Vox-traffic in half-familiar tongues and distorted tech-cant codes, and alongside this its Auguries registered the scattered heat-bloom heartbeats of crude but massive thermic reactors at the heart of huge machines crawling across Medusa's broken lands, and within these the sparse Ӕtheric signature of human life.

The glory of Medusa in the Dark Age of Technology had fallen into a wreckage of devolved ruins and barren rock, its wealth spent and ripped from it during the Age of Strife. But amidst the emptiness and despoil, the Warp-runner's deep searching of the radiation and signals found something else, something unique that all its kind had been tasked to quest for -- a treasure beyond price.

It found a Primarch.

Ferrus Manus

Ancient Remembrancer sketch of Ferrus Manus, Primarch of the Iron Hands Legion; illustration taken from Carpinus' Speculum Historiale.

At the dawn of the Imperium of Man, before the Great Crusade had begun, the 20 gene-children of the Emperor of Mankind, the Primarchs, were scattered across the known galaxy through the Warp in a mysterious accident due to the intervention of the Ruinous Powers of Chaos. The gestation capsules of all 20 Primarchs were stolen from the Emperor's secret gene-laboratory deep beneath the Himalazian (Himalayan) Mountains on Terra and were flung across thousands of light years, all eventually coming to rest on backwater human colony planets.

It was this first touch of Chaos before the Primarchs had even been born that may have corrupted so many of them and laid the foundation for the agonising tragedy of the Horus Heresy that was to come. One of these infant Primarchs turned up on the dark, geologically unstable Feral World of Medusa in the Segmentum Obscurus very near to the Eye of Terror, his gestation capsule burning a trail through the cloud-dominated sky as it impacted the highest mountain on the world, Karaashi, the Ice Pinnacle.

The impact shattered the mountain top, burying Ferrus deep in the ice in a tremendous explosion of steam. The land shook under the impact which could be felt the world over. Mountains were toppled and great chasms were formed as the planet rumbled under the coming of the Primarch. Medusa rumbled with such ferocity that the Medusans later said that many of the world's mountains simply shook themselves to pieces.

Years later that special infant, named Ferrus Manus (High Gothic for "Iron Hand") by the Medusans, walked unscathed and already fully grown from the uninhabited mountain ranges of the far northern wastes where the Ice Pinnacle lay. The legends of the roaming clans, taught from father to son throughout the ages, revolve around the early exploits of Ferrus, who came to be regarded as a great warrior amongst the nomadic clans of Medusa.

No one could match his strength of arm, try as he might to find a worthy opponent. He sought out every physical challenge that he could, always returning victorious. According to one oft-recounted myth, Ferrus once challenged a Storm Giant to a competition of strength. The giant lifted a mountain between his hands and set it back down a Terran mile away. The giant's laugh died when Ferrus lifted the entire mountain range on his back, carrying it to a neighbouring island. The poor, humbled giant was never seen again.

Ferrus travelled the length and breadth of Medusa, becoming well-known by all the clans and coming to know the land itself as no one ever had. He travelled areas that any other man would have found inaccessible. He climbed the highest mountains, he swam the deepest oceans, always pushing his levels of endurance and strength to levels unfathomable to mortal men. His strength and fury made him renowned and feared amongst the people of the clans who valued such qualities highly in their harsh environment.

Ferrus was eventually adopted by the Medusan clans as one of their own. He never interfered in the various clans' conflicts, believing that such competition was healthy for his people and should be allowed to thrive. Because of this impartiality, Ferrus was ultimately accepted universally as an honourary member of every Medusan clan, and great (often exaggerated) legends like the one above were told of his deeds.

One such legend was of the titanic battle between the Primarch and Asirnoth, the Great Silver Wyrm. This tale is recounted in the Canticle of the Travels, an epic Medusan poem of unknown origin that is still taught to the children of the clans at their parents' knees. The Wyrm was said to possess a skin of living metal that was stronger than any armour. It was said that Ferrus spent many days spent tracking the beast through the legendary Land of Shadows, the fearful homeland of the ancients, a place of mystery and terror.

This place, long since lost, was said to be a land forged of metal and stone relics of giant proportions, the remnants of a forgotten age in the galaxy's history. The ghost-spirits of the clans were said to roam there once they left the world of the living. Imperial academics now believe that the description of the Land of Shadows given in the Canticle makes it sound very much like the Necron ruins later encountered by the forces of the Imperium in the late 41st Millennium. As such, Asirnoth may actually have been a C'tan or Necron construct created from their Necrodermis material, which is known to act as a type of "living metal."

Ferrus was unable to defeat the beast with raw strength alone, his punches and blows having no discernible effect. Ferrus was eventually able to slay the creature, drowning it in a river of molten lava despite the agonising pain this caused him, and he bore it stoically. When Ferrus removed his arms from the lava, the Great Silver Wyrm had been completely destroyed, and he discovered that his hands and forearms were covered in the same living metal as the Wyrm's skin, which had flowed across his own flesh, protecting it, even as Asirnoth had been destroyed (or dispersed) by the heat of the molten rock.

This was a substance that was as flexible as flesh yet as strong and impervious as the hardest ceramite. It is known that myths involving Ferrus and his metal hands precede the writing of the Canticle of Travels, but only in the Canticle is this explanation given as to how the living metal came to be fused to his body. The alien metal also altered the Primarch's physiology, for following the battle his eyes turned silver and seemed to lose their pupils, indicating that the necrodermis, if that is what the substance was, had also entered deep within his body.

The reigning hypothesis among Imperial scholars at present is that Asirnorth was a C'tan construct, some kind of guardian creature placed on the planet to protect a possible Necron Tomb or even the resting place of a true C'tan, made of the "living metal" alloy the Necrons called necrodermis. It is possible that Ferrus was in some way polluted or corrupted by the Necron technology in the process of slaying the Great Silver Wyrm.

Ferrus returned to the Medusan clans after his travels, filled with new and wonderful ideas, which he taught to all who wished to learn. He was able to craft strange and powerful tools and objects out of metal, shaping them with his living metal hands without even the need for a hammer or forge.

Under his tutelage, the clans of Medusa became much stronger than they had been before his arrival and became capable of wonders that they never could have imagined possible. It was a time of greatness for the people of Medusa—the civilisation of the clans advanced at a tremendous pace and the Medusan people became strong and proud.

The Coming of the Emperor

The Emperor of Mankind

When the sky was split for a second time in the history of Medusa, the clans were confused, unsure of what this sign might represent. Without a word, Ferrus left the clans immediately and travelled to the landing site of the phenomenon. Solar weeks passed with no news of Ferrus, but before the clans decided what they should do in regard to discovering the fate of their saviour, the sky erupted with titanic electrical storms and the ground shook to savage earthquakes, terrifying everyone.

These events lasted for eight solar days, after which the entire world was said to have fallen unnaturally silent. A single day later, Ferrus returned to the site of the clans' great meeting, escorting an awe-inspiring figure. Stories concerning what acts the two great men performed vary, but most revolve around the common theme of a battle or trial of powers, responsible for the unnatural storms.

Whatever had happened up in the mountains, it was clear to everybody present that there was now a close bond of mutual respect between Ferrus and the Emperor, who had arrived in search of his son. Ferrus Manus soon left with the Emperor to visit Terra, the world of his birth, and become acclimated to the customs and technologies of the Imperium of Man. Yet he promised the clans that he would always return to Medusa, the troubled world that would remain his true home.


The skies of Medusa are always dark and choked by volcanic ash, and its lands are blasted and barren. Massive mountain chains rise high above the land and the peaks of the countless volcanoes are so high that they pierce the black clouds and illuminate them from within as if they were gateways to the infernal. The poles are freezing and savage and the Land of Shadows is a silent region of this barren world that is strewn with alien ruins millions of years old that some Imperial savants believe may belong to the ancient Necrontyr civilisation.

Karaashi, the Ice Pinnacle that the newborn Primarch Ferrus Manus' gestation capsule crashed into when he first fell to Medusa, can still be seen today, though it is said to be half the size it once was. A great gaping hole at its peak that spews ash and steam into the atmosphere is evidence of where the shining light of Ferrus Manus crashed millennia ago.

Still it rumbles with the constant geological anger of Medusa -- a constant reminder to the planet's people of the need for vigilance. The clans of Medusa prepare for that day when the Ice Pinnacle ceases to rumble Medusa's unease. For that day, it is foretold, will mark the second coming of the great Primarch, and with his return, even the volcanoes of Medusa will at last be content.

The Gorgon's Forge

Even after the arrival of the Iron Hands, their homeworld remained sparsely developed, with much of the Medusan populace continuing their nomadic existence aboard vast, armoured crawlers. However, the Chapter does maintain a number of fortified facilities across the planet's surface, each serving purposes both practical and symbolic.

One such location is the Gorgon's Forge, a vast factory complex located near Medusa's southern pole. Playing host to a contingent of Adeptus Mechanicus Tech-priests and rumoured to house a handful of STC fragments, the Gorgon's Forge rings day and night with the clamour of heavy industry.

It is here that Iron Hands vehicles damaged during battle are brought to undergo repairs, and that the majority of the Chapter's Dreadnought sarcophagi lay at rest between battles. Here also are wrought the finest weapons of the Chapter, masterwork examples of the armourer’s art constructed specifically for use by the Iron Hands' mightiest heroes.


"As iron sharpens iron, so truth cuts, and war makes right."

— Ancient Proverb of the Medusan Clans

The people of Medusa are truly a product of their difficult environment. Harsh and unforgiving in nature, Medusans are a fierce and hardy people who cannot afford to brook weakness of any kind in their ranks. Those who are too weak or sick to survive without aid voluntarily surrender themselves to die amidst their world's elements so that their lives will not drain the existing resources and put their friends and family at risk.

The people are organised into nomadic clans and while in ancient times they trudged across the ever-shifting landscape on foot or astride the backs of sturdy beasts of burden, they now travel in vast processions of ramshackle tracked vehicles each as large as a fortress, the acrid stink of a thousand new engines adding to the sulfurous pollution already present in the atmosphere. It is from these hardy and stoic people that the Iron Hands Space Marines exclusively recruit their Neophytes, for the world, its people and the Chapter are one and inseparable.

The Primarch Ferrus Manus saw that weakness could kill the people around him, and came to believe that infirmity of any kind was a plague. He believed that it was better for the weak links of humanity to be destroyed than to have them pose a threat, an unnecessary frailty that would pose a burden to the rest.

On Medusa, weak children were routinely exposed to the elements so as not to place an unnecessary encumbrance on the rest of a clan's community. So too, when the time came that an adult was incapable of providing for the community, that person left their clan. Those who accepted the Emperor's Divine teachings were embraced. Those who did not were cut down without pity. The ruthlessness of the Legion and its Primarch terrified those who stood in the way of their relentless approach, and many worlds turned to the Emperor out of the overwhelming fear of retribution that these callous warriors were becoming renowned for.

Noteworthy Domains

  • Sthenelus System (Primary)
  • Sixteen other star systems held in tributary fiefdom since the closure of the Great Crusade, numerous independently operated outpost waystations and holdfasts established -- full number and position remains unknown.

Notable Locations

  • Felgarrthi Mountains - This is a great mountain range that rises high over the basin of the plains of Medusa. It consists of ten big peaks, each hundreds of metres in height, towering from the storm-blasted summit.
  • The Eye of Medusa - The Eye of Medusa is place sacred to the clans of Medusa deep in the Felgarrthi Mountains region.
  • Karaashi, the ice Pinnacle - Karaashi is the name given by native Medusans to the great Ice Pinnacle where Ferrus Manus originally crashed onto Medusa. However the Ice Pinnacle in the late 41st Millennium is said to be only half the size it once was when the Primarch first came to Medusa.
  • Oraanus Rocks - The Oraanus Rocks is the name given to a mountain ridge that extends for several hundred kilometers, stretching north to south, and consists of ultra-hard lumps of diorite, a metamorphic crystal found only on Medusa. The Oraanus Rocks is where the Trial of Rocks traditionally is held, an early test for Neophytes of the Iron Hands Chapter.

Notable Fauna

  • Mountain Yarrk - The mountain yarrk resembles a cross between a giant leopard and a large primate of Terra.It stands several metres tall with broad shoulders. Its long arms and powerful body are covered with black, shaggy hair and its head was encircled by a lion-like mane. A yarrk was a very fierce beast and was frequently hunted by the young Medusan clansmen in attempts to impress the Iron Hands into recruiting then as neophytes.
  • Oryx - An oryx was a large quadruped that possessed a great rack of antlers that was native to Medusa.



Warhammer 40,000 Grim Dark Lore Part 13 – Lost and Found


  • Black Legion - A Codex: Chaos Space Marines Supplement (6th Edition), pp. 39-40
  • Codex: Space Marines (6th Edition), pg. 68
  • Codex: Space Marines (5th Edition), pg. 30
  • Deathwatch: First Founding, pp. 7-8
  • Index Astartes III, "Hand of Justice - The Iron Hands Space Marine Chapter"
  • Index Astartes IV, pp. 47-48
  • The 13th Black Crusade (Background Book) by Andy Hoare, pg. 73
  • The Horus Heresy - Book Two: Massacre, pp. 64-67, 70-71
  • The Eye of Medusa (Novel) by David Guymer, Chs. 2, 5, 7
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