Lore Post - the firstborn legions part one.

 

Firstborn Legions Part One.

Based on Pre - Heresy Lore.
After the nascent Primarchs were stolen away into the warp by the Ruinous Powers, the Emperor’s grand design suffered a devastating blow, one so severe that even he must have wondered whether his vision could still be realised. Yet, for reasons never fully explained, he became convinced that the Primarchs hadn’t been destroyed, but scattered across the galaxy. With that belief guiding him, he reshaped his plans. The Great Crusade would begin without his greatest generals, and the search for them would unfold alongside it. Each Legion would march with its own network of informants and covert operatives pushing ahead of the Crusade’s advance, listening for rumours, myths, or any sign of beings as extraordinary as the Primarchs. Figures of such power would never go unnoticed for long. The first waves of Legionaries were drawn from the varied populations of Terra. Still, over time, each Legion would be reforged with recruits from the worlds where their lost Primarchs were eventually found, binding father and sons together once more.




Dark Angels - 1st Legion

Primarch - Lion El'Johnson - 11th Primarch found.

Homeworld - Caliban (Destroyed), now the Rock.
Caliban was a world of dense, brooding forests, its wilderness shaped by the presence of twisted, predatory creatures touched by the warp. Human society survived in isolated pockets, organised into a feudal structure of lords and knightly orders who ruled from scattered stone fortresses. Life on Caliban was defined by a constant balance between internal rivalries and external threats: the nobles waged their ritualised wars of honour, yet all were united in the ongoing struggle to keep the monstrous denizens of the deep forests at bay.

Legion Combat Doctrine - 
The Dark Angels broadly follow other Astartes legions in their organisation and battlefield doctrine, but the character of the First Legion is unmistakable in how they wage war. Their reputation for sheer, immovable resolve is well earned. When the sons of the Lion commit to a position, they do so with a level of discipline that borders on ritual. In battle, the Dark Angels are known for holding their ground against overwhelming odds, maintaining formation long after other forces would have withdrawn. Even when a tactical retreat might offer a clearer advantage, they are inclined to stand firm, trusting in their training, their firepower, and their own unshakeable determination. This stubborn refusal to yield is not recklessness, but a deeply ingrained aspect of their identity, a legacy of the First Legion’s long history and the weight of duty they carry.

Legion Early Details - 
The First Legion was created on Terra, its gene‑seed crafted from the genetic template of Lion El'Johnson. They fought in the closing stages of the Unification Wars, proving their worth in the Emperor’s final push to bring Old Earth under a single banner. Their earliest recorded action as a Legion came during the suppression of an attempted coup, when they were deployed to eliminate a coalition of surviving Thunder Warriors and Imperial officials unsettled by the Emperor’s increasingly unilateral rule. It was the first time Space Marines had ever taken to the field, and the First Legion set the standard by which all others would be measured.

xxxxx - 2nd legion - all records deleted

Emperors Children - 3rd Legion

Primarch - Fulgrim - 5th Primarch found.

Homeworld - Chemos (Destroyed) now the Eye of Terror.
Chemos had been settled as a mining world in ages past, but during the Age of Strife, it became isolated from the wider Imperium by violent Warp storms. As the centuries wore on, the planet’s resources dwindled, and even basic sustenance became scarce. Food production could no longer sustain the population, and survival increasingly depended on a network of fortress‑factories that took over every aspect of industry. Life on Chemos became a cycle of unending labour: citizens worked the vapour mines and synthesisers without pause, while art, leisure, and any form of recreation were gradually abandoned in favour of efficiency. Shrouded by dense nebula clouds, the world knew no true day or night, only a constant, muted grey that defined existence for its people

Legion Combat Doctrine -
The III Legion pursued excellence in every aspect of their existence, holding themselves to a standard that allowed no compromise. Each warrior trained relentlessly for his designated role, whether infantryman, gunner, driver, scout, or marksman, dedicating every waking moment to refining his skills. Nothing on the battlefield was overlooked. Terrain, weather, deployment patterns, reserve placement: all were studied, assessed, and folded into their doctrine with meticulous care. 

Chance had no place in their approach to war. In combat, the Emperor’s Children displayed the same courage expected of any Space Marine, but their resolve was strengthened by a personal conviction in their duty. They fought with equal commitment whether engaged in a full planetary assault or a routine patrol, and it became widely accepted that no warrior of the III Legion had ever broken in battle. Their expectations extended to those who fought beside them. Allied forces, whether mortal regiments or fellow Astartes, were expected to match the Legion’s precision and discipline, and any sign of hesitation or inefficiency was met with little tolerance. At the heart of the Emperor’s Children lay a simple guiding principle: to lead by example. It shaped their culture, their training, and their conduct in war, leaving little room for any approach that fell short of their own exacting standards.

Legion Early Details - 
When Fulgrim was finally united with the Legion that carried his genetic legacy, he did not encounter the grand host many of his brothers found waiting for them. Instead, he inherited a force reduced to barely two hundred Astartes. A catastrophic failure in the early development of the III Legion’s gene‑seed had crippled its growth, leaving it far behind its peers in strength and numbers. Until the Legion could be rebuilt, Fulgrim and his warriors were placed within the ranks of another force, fighting alongside a more established brotherhood while their own recovered. The Legion chosen for this integration was the Luna Wolves, commanded by Horus Lupercal. In Horus, Fulgrim found not only a mentor in the arts of war but a companion whose skill and presence shaped his early years as a primarch‑commander. It was under the banner of the Luna Wolves that the III Legion first began to reclaim its place among the Emperor’s sons.

Iron Warriors - 4th Legion 

Primarch - Perturabo - 12th Primarch Found.

Homeworld - Olympia - now Daemonworld Mendrengard.

Olympia was an ancient human colony located in the marches of the Ultima Segmentum, far across the galactic core from Terra. It belonged to a cluster of worlds believed to have been heavily settled during the later years of the Dark Age of Technology. Although Olympia emerged from the Age of Strife largely intact, its scientific knowledge and industrial capability had regressed to a fractured, pre‑atomic level. What remained had stabilised into a complex, highly stratified feudal society. The planet itself was rich in organic resources and a wide range of mineral forms, but its fissile materials and easily accessible conductive metals had long since been strip‑mined and exported off‑world. This depletion placed a hard limit on Olympia’s technological development. Its geography added further constraints: vast, near‑continuous mountain ranges dominated the surface, leaving little room for large‑scale agriculture or urban expansion. These conditions shaped a distinctive culture, one that developed into a mosaic of independent city‑states and subordinate satrapies, each navigating the challenges of a world defined by scarcity, isolation, and rugged terrain.

Legion Combat Doctrine -

The Iron Warriors approach warfare with a methodical clarity that defines their entire Legion. Every engagement begins with a sustained artillery barrage, delivered with precision and supported by a detailed fire plan that assigns each weapon to its most effective target. When the opportunity arises, they coordinate their bombardments with Titan Legions, adding even greater weight to their already formidable firepower. This focus on artillery and mechanised strength makes the Iron Warriors particularly effective in siege warfare and in driving armoured assaults deep into enemy territory. Fortifications play a central role in their doctrine. Wherever possible, the Iron Warriors construct fieldworks designed to tie down the largest number of enemy forces while committing the fewest of their own. By doing so, they keep the majority of their Legionnaires rested and ready for decisive assaults, allowing them to apply pressure where it matters most. In planetary invasions, their strategy begins long before the first drop‑pod descends. The Iron Warriors initiate their assaults with overwhelming orbital fire—whether nuclear, plasma, viral, or chemical—aimed at breaking the enemy’s will to resist before a single Astartes sets foot on the surface.

Legion Early Details.

For decades upon decades, the Iron Warriors were basically the Great Crusade’s go‑to battering ram, the Legion you called when some fortress was too stubborn, too proud, or too well‑built for anyone else to crack. If there was a citadel that needed levelling or a defensive line that absolutely had to fall, the IVth were the ones who made it happen. Over time, their name became shorthand for brutal, grinding warfare and an almost obsessive mastery of siegecraft, whether they were tearing walls down or holding them against impossible odds. And at the centre of it all stood Perturabo. Before the Heresy twisted everything, he already had a reputation as a cold, razor‑sharp commander, the kind of warlord who could look at an enemy position and instantly spot the flaw everyone else missed. He didn’t just exploit weaknesses; he punished them. For Perturabo, defeat wasn’t an option, and victory was worth whatever it cost in blood, sweat, or shattered stone.

White Scars - 5th Legion

Primarch - Jaghatai Khan - 15th Primarch found

Homeworld -  Chogoris (Known to the Imperium as Mundus Planus)

According to the old Liber Historica Vangelia, Jaghatai Khan first set foot on a world Imperial maps called Mundus Planus, though the people living there simply knew it as Chogoris. Chogoris itself was a lush, beautiful place: rolling green plains, sharp mountain ranges, bright blue seas. When the Great Crusade reached it, the planet was sitting at a late‑medieval, early‑Renaissance level of tech, black powder weapons were only just becoming a thing. At the time, most of the world was ruled by a powerful feudal empire led by the Palatine. His armies were disciplined, well‑armed, and very good at winning wars. Heavy cavalry in full plate and tight ranks of infantry had carried him through every campaign. Out west, though, the empire met the “Empty Quarter,” a huge, windswept steppe roamed by nomadic horse tribes. These riders lived in tents, followed the seasons across the grasslands, and spent their winters tucked into the sheltered valleys of the Khum Karta Mountains.

Legion Combat Doctrine.

The White Scars have spent ten thousand years sharpening their way of war, but at their core, they still fight like the old Chogorian steppe tribes. Those nomads might have looked wild to outsiders, but they were sharp‑minded hunters and masters of reading the land. A White Scar doesn’t charge in like a berserker. He strikes like a perfectly balanced hunting spear, fast, precise, and aimed exactly where it hurts most. Their whole style is built around terrifying speed and crushing impact, but never at the cost of control. Preparation is everything to them. They scout hard, plan carefully, and line up every contingency before they commit. When the moment comes, the strike lands clean, coordinated, and devastating. Each White Scars brotherhood basically operated as its own fast‑moving strike force, fully equipped to get its warriors onto a battlefield at the blistering speed the Legion was famous for. Because of that, they leaned hard into anything that flew or skimmed above the ground. Smaller craft were their favourites,  easier to maintain, quicker to deploy, and far more agile. Everyone knows about their jetbike swarms, Scimitar, Shamshir, Falcata, the whole lot,  but the brotherhoods didn’t stop there. They fielded plenty of Land Speeders, Fire Raptor gunships, and even select armoured vehicles when the situation called for it.

Early Legion Details.

Back then, the title Master of the Vth Legion didn’t mean much. The White Scars were scattered across the galaxy, fighting a hundred different wars with no real centre. Jaghatai Khan basically inherited a Legion of wanderers, a situation that would’ve frustrated most of his brothers, but suited the Great Khan perfectly. Just like he’d done on the plains of Chogoris, he set out to forge a unified army from scattered, independent warrior bands. He started with his own people, recruiting Chogorians old enough and tough enough to survive the transformation into Space Marines. 

They became the new heart of the Legion. At the same time, he sent out a great summons, calling every far‑flung company of the Vth, the Pioneer Companies roaming the galaxy, to gather under his banner. That call travelled slowly, carried by astropaths and courier ships. After his rediscovery in 865.M30, Jaghatai waited almost a decade for most of his warriors to return to Chogoris. Some were so deep in war zones or so far from Imperial space that they didn’t make contact until the early 31st Millennium. The force that finally gathered above Chogoris in Jaghatai’s early years wasn’t a Legion in any real sense. Each company stuck to its own, eyeing the others with suspicion and a fair bit of disdain, more strangers than brothers. When the Khagan brought them together on the plains of the Empty Quarter, he saw warriors from a hundred worlds, each carrying their own colours and traditions, connected only by shared gene‑seed. Jaghatai fused those thin genetic ties with the culture of Chogoris, using the rituals of the hill tribes to bind them into something new. Through blood, pain, and sworn oaths, they became the White Scars, loyal to the Khagan and, finally, to each other.

Space Wolves  - 6th Legion

Primarch - Leman Russ - 2nd Primarch found 

Homeworld - Fenris 

Native Fenrisians have long accepted the cycle of destruction that sweeps across their world every Great Year. They meet the planet’s endless upheaval with a fierce, almost joyful warrior pride, embracing the mutability of the land as part of their identity. Only on the northern polar continent of Asaheim are Human communities shielded from the worst of Fenris’ murderous climate. There, life clings on — and evolves into forms found nowhere else on the Death World. Asaheim teems with colossal ice bears, towering elk, and shaggy mastodons, but also stranger beings: snow trolls lurking in frozen caverns, shape‑shifting dopplegangrels stalking the blizzards, and the great white wyrms that burrow through glacier and fjord alike. Yet the most dangerous of all are the native Fenrisian Wolves. Semi‑sentient and cunning, their minds are as sharp as their fangs, and the largest among them rival any apex predator that prowls the frozen wastes.

Legion Combat Doctrine.

The Space Wolves don’t fight quite like the other Space Marine Chapters. Each Great Company is composed of different kinds of squads and Packs, each with its own role on the battlefield. As a Space Wolf gets older and survives more battles, he moves up through these roles, gaining experience (and longer fangs) along the way. If he proves himself brave and deadly enough, he might be invited to join the Wolf Guard, or even rise to become a Wolf Lord. Most Space Wolves start out as Blood Claws. They’re young, loud, and absolutely desperate to prove themselves.

 Blood Claws charge into battle in big, howling groups, usually leading the assault and throwing themselves at the enemy with zero hesitation. If they manage to survive long enough to cool their heads a bit, they become Grey Hunters, solid, reliable warriors who’ve learned to balance ferocity with discipline. Eventually, when a Space Wolf has seen centuries of war and his hair has gone grey, he might join the Long Fangs. These Veterans are calm and steady even when everything around them is exploding, which is why they’re trusted with the heavy weapons. They’re the ones laying down precise, devastating fire while everyone else is in the thick of it. The strongest and most heroic warriors can go even further. After performing some awe-inspiring feat of courage or skill, a Space Wolf might be elevated to the Wolf Guard. These elite fighters either lead younger Packs into battle or serve as the personal bodyguard of a Wolf Lord. Armed with the best gear in the Great Company, they’re terrifying in close combat, and very few enemies can stand against them.

Early Legion Details. 

When the Emperor finally took Leman Russ from Fenris, He wasted no time teaching the Wolf King about the wider Imperium, its technology, its armies, and the sheer scale of the galaxy beyond his icy home. Russ picked things up fast. In just a few short weeks, the Emperor decided he was ready to take command in the Great Crusade. That’s when Russ met the warriors of the VI Legion, Space Marines created using gene‑seed grown from his own DNA. From that moment on, he became their father and their lord, and the Legion took on the name they’re known by to this day: the Space Wolves. The Emperor equipped Russ for war with a blessed suit of Power Armour and replaced his old blade with the legendary Frostblade Mjalnar,  forged using the teeth of the Great Kraken Gormenjarl. 

According to the sagas, the weapon was sharp enough to split Fenris’ ice mountains clean in half. When Leman Russ left Fenris, he didn’t go alone. Several hundred Fenrisian warriors went with him, men who, despite their age, had survived the brutal process of becoming Astartes, at least in part. Plenty died trying, but far fewer than anyone expected. There were two big reasons for that. First, Russ’ own gene‑helix stabilised the VI Legion’s gene‑seed, fixing most of the problems that had plagued earlier recruits. Second, Fenrisians themselves were unbelievably tough, shaped by generations of surviving a world that really shouldn’t support human life at all. These warriors became Russ’ first Varagyr, sometimes called “Varangii” in old Imperial records, but more literally “Wolf Guard.” They were his sworn companions, loyal enough to follow him off their frozen homeworld and into the stars, even though they barely understood what that meant. 

Their devotion mattered more to Russ than the raw power of the VI Legion Astartes he’d been given to command. Those warriors might have been strong and savage, but they hadn’t earned his trust yet. This was the first lesson Russ taught the VI Legion: loyalty and proven brotherhood mattered more than engineered strength. And it was an early sign that under the Wolf King, his Legion would never be quite like any other.