The Primarchs.
Lion El'Johnson Primarch of the 1st legion Dark Angels.
The planet of Caliban was covered in dark forests full of chaos, twisted creatures that made life incredibly difficult for the humans that lived there. To be alone in the forests meant a certain horrific death; to survive, the inhabitants of Caliban had to live in fortresses and rely on knightly orders to be their protectors. The planet had been cut off from Terra thanks to the violent warp storms during the age of strife, and as a result, the populace devolved into a medieval feudal level of technology and civilisation. With the devolution, the majority of the people were ruled over by a small warrior elite. This noble class were great warriors, from birth brought up to be brave and to have no fear of death when facing the creatures of the forests. The knights had access to some very rare technology. They went to battle in a very basic form of power armour and used chainswords with bolt pistols. no other advanced technology existed on Caliban. The knights rode large battle horses named Destriers. They conducted long patrols into the wilderness to try and help to make life even a little better from the constant, never-ending struggle it was for the people of Caliban. It was during one of these patrols that Luther would first meet the young and feral Primarch who would go on to become Lion El'Johnson.
The young primarchs' early years have been lost to time. The only person who knows for sure has never been open about it. What is known is that he crashed into the Caliban jungle. The knights that found him said that he looked to be a decade old, but with a primarch's accelerated growth, it is unknown just how long he was there alone against the native beasts of the forest. The heavily fortified towns that lay close to the boundaries of the forest had a strange urban legend about a nature spirit of smaller stature than a man, but humanoid, that would occasionally be seen but would not approach the town border. This nature spirit was said to have been around for over a century, and at the time, it was said to be the primarch, but this has never been verified. The warp is known to play fast and loose with time and reality, but it is unknown if it played a part here. Luther adopted the young feral child and brought him into civilisation for the first time.
In a short space of time, the Lion had rapidly integrated with the knightly way of life and proved himself to be a capable fighter and strategist. Some say this is where the first seeds of jealousy were planted in the heart of Luther. After El'Johnson had reached maturity, he had managed to reach the highest ranks of the order and called for a great crusade to wipe out the beasts that featured in so many people's nightmares. After a solar decade of hard fighting and planning, the crusade was declared won. in this time, the orders ranks had swollen to numbers never before seen due to people flocking to fight with the Lion. The crusade was not universally popular with the other knightly orders on Caliban, and any that did resist were wiped out to the last man. Luthor at this point had dedicated his whole existence to the order, and at the end of the great crusade, the title of Grand Master of the Order was given to the Primarch, and Luther could only watch and burn with jealousy. Shortly after this title was bestowed upon the primarch, the fateful day of the Emperor's arrival would come to pass. When the Master of Mankind first stood in front of the Lion, the Primarch felt an instant connection and dropped to his knees, swearing fealty to the golden haloed being in front of him. On meeting some of his sons for the first time, the primarch challenged the captain of the company present. After an intense duel, the Lion would grant his sons their new name, the Dark Angels, and the Lion El'Johnson would be their Primarch and general.

Perturabo Primarch of the 5th legion Iron Warriors.
The planet of Olympia was a civilised but fractured world when the young Primarch Perturabo crashed. The details are mainly lost to time, and the fact that the lord of iron was always so secretive with his own history and inner nature. Perturabo was found outside in the wilds of the planet. The leader of the settlement he was taken to was known as the Tyrant, and he dispatched his guards to bring the unusual child who had been seen roaming the wilds. The city-state of Lochos was ruled with an iron fist by the Tyrant named Dammekos. He had heard stories of the young boy wandering the wilds, surviving by renting out his arm as a mercenary and as an artisan of phenomenal talent. The Tyrant really wanted to possess Perturabo's formidable engineering mind to crush his enemies and ensure that he would keep control of Lochos with no contenders. When the Tyrants' guards brought the sullen and taciturn boy to him, he demanded a test of his abilities. Perturabo was forced to fight multiple warriors from the Tyrant's household guard, and very taxing puzzles testing every facet of knowledge. These tests posed no threat to Perturabo; he passed through everyone easily and amazed everyone who witnessed this. The Tyrant offered the young Primarch a place in his household. The deal was struck, loyal service from Perturabo and protection from the other Tyrants and their retainers. One of the strangest aspects of Perturabo was that he could always see the cosmic scar he would come to know as the Eye of Terror. His early life was lived under the watchful eye of the people of Lochos. Perturabo learned many lessons from his adoptee culture, the art of siege warfare. He studied this form of war diligently; he learned the theory and practical skills that would go on to make him the skilled combatant he would come to be.
As his life on Lochos progressed, so did his disdain for the mortals and their petty natures that surrounded him. Against the oldest of traditions on Olympia, when Perturabo reached his majority, he refused to honour the family he had been adopted by, taking a name from their storied history and kept to Perturabo, later rumoured to be from the Age of Strife era humanity. As a result of this majority he was able to turn to war and was allowed to command troops. Only allowed small commands to begin with, after many victories from the Primarchs' brilliant command skills and understanding, he shot up the ranks at a frightening pace. Dammekos reaped the rewards of these many victories; mercenaries and war artisans flocked to his banners, wanting to learn from his unbeatable general. As Perturabos' star rose, the people of Olympia were amazed at his new weapons, munitions, and many ingenious inventions to cause death on a mass scale. He was soon given the name the Hammer of Olympia. After a period of time where Olympia stayed as violent and riven by war as ever, just more and more violent, the Great Crusade came to the planet, and it became immediately clear that another of the Emperor's sons was found. It is said that acceptance from the Primarch was immediate for his real position in the universe, and in the plans of the Emperor was immediate, and he quickly went on to take control of his legion. He named them the Iron Warriors, they would come to be a fearsome force when holding siege to enemies, and eternal dislike and eventual hatred of the Imperial Fists legion.

Mortarion Primarch of the 14th legion Death Guard.
Barbarus was a planet of steam-powered technology adapted by Warp powers used in Necromantic ways. The planet was perpetually wreathed in a poisonous fog that would become more dangerous the higher up you went. The population was split between the controlling warlords and Human settlers trapped on the planet since their original stranding there in the Age of Strife. The inhuman warlords wielded necromancy powers that constantly kept the humans in a state of abject terror. Not being happy with just abducting the humans on the planet for their hideous experiments and tortures that would make a Drukhari blink, they stitched them up in various new ways and sent them to attack the village, always making sure there was something for their loved ones to recognise them by in their new form. It was in this horror of a world that the young Mortarion would come to be found. On the battlefield of the highest ranked overlord's latest victory, a screaming child was found. This was incredibly strange, as a normal human child should have been dead in seconds. The overlord was named Necare. He took the child, intending to bring the child up as his heir. This would not be a blessing or a good twist of fate; Mortarion would be nothing other than another weapon of terror and death incarnate. Death would be ever-present in the Primarch's life from this point, even his name meant 'child of death' in the local High Gothic dialect. The future Death Lord was to grow up as a virtual captive, kept in a small tower built at the limit in the fog of what even his vastly superhuman biology could cope with. The high overlord lived at the peak of the mountain where even the Primarch could not tread.
The Primarch had a thirst for knowledge and an intellect that was unmatched anywhere on Barbarus. His keeper made sure to keep his charge trained in every subject of lore, no matter how obscure, even arcane sciences were not off the curriculum. This would be the point that started Mortarion's hatred for psykers; his mind constantly strayed more and more towards the pitiful lives that went on down in the valleys where the poisoned fog didn't cover, but the evil of the overlords did. Mortarion broke free of his prison tower to get the answers he knew he would not get from the high overlord. On reaching the humans below, the Primarch saw that they were pitiful in their terror and squalid living conditions. He pledged to them that he would free them. They took a long time to trust him; he was just some deathly pale, unusual human-like creature from the mountains. it would not be long before he could prove his worth to them. Creatures sent by one of the other many warlords attacked the humans, and Mortarion dived in to defend them with a simple farming scythe, destroying the beasts in short order, then going on to hunt down the attacking warlord who had retreated into the fog, thinking he would find safety. After this event, he began to train the villagers and help them develop ways of defending themselves, turning their villages into strong points and unifying the scattered human survivors. The most resilient and toughest of villagers were recruited into a single band of elite fighters, which he named his Death Guard. he helped to create rudimentary armour and breathing equipment to allow them to go further into the deadly fog.
One by one, the warlords were butchered by the Death Guard until only Mortarion's adoptive father remained in his peak-top holdout. As the preparation to assault this final fortress was being undertaken, the Primarch found himself reluctant to attack and retreated into what would be his usual way of dealing with any problems or choices; he retreated into a moody silence and brooded on his pain and anger. During this time, a stranger appeared on Barbarus. He issued a challenge to Mortarion: they would both race to reach the stronghold of the high overlord, and whoever got there first and killed the overlord would be the winner; the loser would swear fealty and servitude to the winner. This proved to be a short challenge, as the Primarch climbed higher into the fog, parts of his armour were rotting away, and he was quickly being overwhelmed by the poison. As he started to blackout, the final thing he saw was a mocking Necare standing ready to take his life, until out of nowhere, the stranger appeared and killed the overlord there and then. The stranger revealed himself to be the Primarch's true father, the Emperor of Mankind. Mortarion was always quick to take offense and long to forget any slight, would consider that this was the worst outrage he had ever suffered; the High Overlord's life was his to take and not the Emperor's.

Lorgar Aurelian Primarch of the 17th legion Word Bearers.
The incredibly charismatic (even for a Primarch) Lorgar found his start on the hyper-religious world of Colchis, a desert planet once a world of advanced technology brought low by Old Night and the horrors that followed. Originally found by the nomadic tribal outcasts called 'the Declined', they adopted the infant Primarch and named him Lorgar or Rain-caller in their language. He was only with them for 17 days and was already the size of a small child when an exiled priest named Kor Phaeron and his caravan stumbled upon them. He had been exiled because his rhetoric was much more aggressive than the mainstream religious leaders of Colchis were at that point; the religion was known as the Covenant, which worshiped four deities that were actually the Chaos Gods in a kinder fashion. Kor Phaeron was instantly convinced of the Primarch's potential and future greatness. He convinced the child to join him and to become his disciple, to hide where the Primarch had initially been found. He killed the Declined and made sure that the truth would never come to be known.
Kor Phaeron was not a benevolent teacher, far from it; he forced Lorgar to endure vicious and unrelenting emotional and physical abuse. All the Primarchs were blessed with a thirst for knowledge and incredibly heightened intelligence. Lorgar's need for knowledge presented with a religious fervour and a drive to learn everything he could about the powers that the covenant worshipped, every scrap of theology he could find, he absorbed and researched. He soon came to the belief that there was a singular being ahead of the pantheon of 4 that the covenant believed in, which was routinely and severely dismissed as heresy by Kor Phaeron at first. Causing punishment and further abuse as the exiled priest tried to exert his will over Lorgar, even forcing the other members of the caravan to abuse him. Instead of harbouring resentment for Kor Phaeron, Lorgar actually became intensely loyal and would go on to save his life when the caravan members rebelled after yet again being forced to chastise the Primarch.
After the mutiny attempt was violently stopped by Lorgar, the abuse would stop, and Kor Phaeron named him 'the Bearer of the Word'. From this point, the fame of Lorgar would spread around Colchis, and the caravan would roam freeing slaves all across the desert, forming a great army known as the Godsworn. This army forced its way to the capital city of Vharadesh, and after a rousing, fiery sermon at the gates, the inhabitants would turn on the leaders of the Covenant and present their bodies after opening the gates to the Godsworn. This would begin a crusade going from city to city, converting either peacefully when accepted or violently if opposed. After years of fighting, the final city lay before them. The city of Gahervaria was protected by a piece of technology from the Dark Age of Technology called the storm generator, which created a protective area around the city of a raging storm. This looked to the everyday people like a miracle from the gods, forming to deny the false prophet of Lorgar. As he approached the storm, it parted around him, allowing his army to force its way into the city and claiming it for the Bearer of the Word.
Finally completing his crusade, Lorgar named Kor Phaeron as the High Priest of the Covenant and then announced to his followers that there was more to be done. This caused a great schism to form due to the jealousy of the former covenant priests. During this time, Lorgar became convinced that a warlord in gold was coming to Colchis, and he began to preach to the people that the one true God was coming. This provoked those disaffected priests who had caused the schism to act; they declared him a heretic to the old ways, and they tried to arrest Lorgar for punishment, severely misjudging his popularity with the masses, causing them to be killed. The so-called Schism Wars lasted for 6 years and ended when the high temple of the covenant was stormed and the monks there were exterminated. It was said that a full third of the Colchis population had turned against Lorgar and his followers. Their response was without mercy, and a great purge was conducted to remove this dissenting third and allow Lorgar to reign as the Archpriest of the now reformed Covenant. Less than a year after the final peace was found, the Emperor of Mankind found his way to Colchis to reclaim Lorgar for the Great Crusade. Although Kor Phaeron was much too old to be made into a Space Marine, Lorgar made sure he was given the best Genetic and technological upgrades to make him as close to one as was possible. Named as the Primarch of the Imperial Heralds Legion made from Lorgar's own genetic material, he quickly made them his own and changed their name to the Word Bearers Legion.

Jaghatai Khan Primarch of the 5th Legion White Scars.
When the Primarchs were scattered from Terra, the Primarch who would become known as Jaghatai Khan landed on the fertile world of Chogoris. With its wide-open plains and vast expanses of grass, mighty white mountains, and deep blue seas, Chogoris was a slightly developed world, managing to rebuild itself to a late Renaissance, old-earth level of technology. The dominant power on the planet was a feudal aristocracy led by the Palatine; his army was well supplied with plate-armoured horsemen, blocks of disciplined pikemen, and arquebus-equipped troops. This great army won every battle it faced with overwhelming force. To the west lay the Empty Quarter, a vast Grassland inhabited by various wandering tribes of horsemen similar to the tribes of Mongolia in Terra's distant past. The empire of the Palatine led forces there to capture slaves or hunt these tribes for fun and practice for new troops. It was here that the young Primarch was to be found; the tribe of the Talaskers and their Khan Ong (tribe leader) were the ones to find and adopt the remarkable child they had come across. They came to see the Primarch as a gift from the gods and said that he had 'fire in his eyes'. This opinion was not shared by the other tribes of the great grass expanse; they came to resent the remarkable adopted child because he had a vision of the nomadic tribes that didn't involve warfare between them and a unified empty quarter. One of the defining moments for him was when his adoptive father was slain by a rival tribe. In revenge, he led a reprisal raid that ended with the slaughter of every single member of the tribe responsible; he burnt their yurts to the ground and mounted the leader's head on his tent. This proved to instill the Primarch with a personality of fierce honour, loyalty, and utter ruthlessness to anyone who crossed him. The assassination of his father would be the start of a unification crusade for all of the Empty Quarter. As they were defeated, the tribes would be absorbed by the Talaskers, forcing the end of tribal warfare and resolving the generational grievances and differences.
During a migration to the winter camps, Jaghatai was trapped in an avalanche that killed the normal men with him and he was captured by one of the Palatines hunting bands that included his son. all that would return to the empire would be a mutilated rider carrying the head of the son, with a message stating that the people of the Empty Quarter would no longer be the playthings of the Palatine. Once the snows had cleared, the Palatine sent a massive army with the mission to wipe out all of the tribes once and for all. This would prove to be a gross underestimation of the abilities of the Khan and his new tribe. The heavily armoured and clumsily moving army could not catch up with the fast-moving archers on horseback, the rain of arrows hammered into the ranks of warriors relentlessly, almost to the last man, and the Palatine managed to escape along with his bodyguard. Jaghatai was announced as the Khan of Khans and rightful ruler of his people. From this point, the conquest of the singular continent of Chogoris would begin, as the Khan's armies besieged the Palatines' cities, and a choice would be given: surrender or die. Most would surrender, but those that did not were annihilated completely, utterly removed with ruthless precision. when the army reached the Palatine's palace, a further choice was given: death or the Palatine's head on a spike. This was duly delivered by the inhabitants, and the planet's conquest was complete. As the planet's ruler, Jaghatai kept the peace with a threat of utter destruction to anyone who broke the peace. After only a short while on the throne, the Emperor of Mankind would get to Chogoris to claim another lost son, and his true destined role would begin.

Konrad Curze Primarch of the 8th legion Night Lords.
Nostramo was a cursed world of violence, misery, and perpetual darkness; it was a world in the light of a dying sun. Criminal gangs ruled the hives, screams, and gunfire accompanied people's sleep. It was a mining world of adamantium; this ore was demanded in massive quantities for use in power armour. The Primarch's arrival in this world caused a gigantic scar on the land where it ploughed through anything unlucky enough to be in its way. Curze was the only Primarch never to be adopted or claimed in any way. The harsh lessons of life were taught to him by experience and his own intuitive knowledge imparted by the Emperor's gene forging. He survived by being ruthless and determined to live; he ate any feral creature that he could catch. The Primarch was plagued by precognitive visions that showed him exactly how he would die and everything that would come to happen in the Horus Heresy.
Curze would know death intimately from a young age, as he would slay anyone who sought to prey on him. The constant screams and crime were everywhere he would come to realise that he was superior to the cattle that he killed so easily. He learned that he could learn from tasting the flesh of those he killed, but this was only partly the reason he did it. Through it, he learned the language of Nostromo, and the murders they had committed were imprinted in his mind's eye. He chose to bring this to an end by bringing his own form of twisted justice; he started by killing any who crossed his path. The thugs, thieves, and murderers began to disappear from the streets, their bodies appearing mutilated and in public places on display for all to see. Then this wasn't enough; whole gangs would go missing, their flayed skin on show for all to see. A name began to follow his deeds, whispered with dread, the fear lay heavily everywhere he had been, the name was Night Haunter, people dreaded to say it. He started by only getting involved when he saw the perpetrators of these crimes committing them; he then moved on to hunting down those he suspected of committing them. After a short period, he was no longer happy hunting the dregs of society; he began to hunt civic leaders and people of a higher station. The remains were often left in such a way it was impossible for anyone to identify. Within just a year, the crime rate fell to near zero. The whole world controlled by the fear he might appear to repay their transgressions, he would go on to be claimed as the first absolute monarch Nostromo had ever known.
The Dark King had taken the throne and brought peace and justice by the way of fear and terror. He ruled with reason and his own justice until a whisper of an injustice came to his ears; he would then hunt the offender down through the dark streets and torture them, and leave the remains mutilated but not beyond the ability to identify. Nostromo became more efficient and honest than ever before. Exports tripled, and there were no bribes or unlawful taxes taken by corrupt officials. Decades passed, and he no longer needed to hunt; the fear of him appearing at their door stopped people from even daring to be accused of misdeed. The very rare instance of someone breaking his law caused them to be tortured on live picter screens, their screams turned up for everyone to hear and know what awaited anyone who still hadn't learnt the Dark King's way. To this fearful, controlled world, the Emperor would arrive. Curze had foreseen this in his dreams. When he arrived, the golden light of the Master of Mankind blinded the people who looked too close at him. He took Curze away to join the Great Crusade, and in his absence, the people still feared.

Angron Primarch of the 12th legion World Eaters.
To call the world of Nuceria a civilised world would depend on which side of the social ladder you belonged to; the wealthy oligarchs of the planet lived a decadent lifestyle of opulence and pleasure, able to enjoy all manner of luxury that could be found. The technologically advanced world offered a multitude of pleasures and enjoyments. On the other side of the scale, the poor lived in abject poverty, constantly reminded of their betters by the towering manors and villas watching over them all around. The only escape offered to them was the gladiatorial games, which were provided to act as a distraction, also to try and trick the populace into thinking that at least they were not at the very bottom of the ladder. The Gladiators were cybernetically enhanced and their aggression goaded by all manner of twisted methods, from drugs and punishments to the worst of all, called the Butcher's Nails. These archaic cortical implants were driven into the brain to artificially force increased adrenaline production to swamp the brain of the fighter, causing greater strength and aggression at the cost of all emotion apart from hate. By rewarding anger and violence with a brief reprieve from the pain it also caused a complete lack of care for one's own mortality, and injuries were ignored, anything to get the all too brief flickers of pleasure.
These Gladiators were provided by slavers who roam the planet looking for ideal candidates to drag into this living hell for other amusements. As fate would have it, or maybe by the will of the blood god itself, Angron was found by one of these. The slaver chanced upon him as he lay severely injured with the corpses of many xenos all around him; it is thought now that they were Aeldari. The psychically attuned beings may have known what was to come from the young Primarch in the future, maybe not, the fae creatures would never give a direct answer if asked for an answer. The boy was taken to the ruling elite of the planet known by everyone as the 'High-Riders'; they would come to name him Angron, meaning 'child of the mountain'. Before he had even healed properly he was thrown into the arena to face his first challenge, the arenas would change with every bout to add a challenge to add to the excitement, this particular one was a tall single ziggurat in the middle, the arena would slowly fill with acid and the winner would have to fight his way to the top, getting through hundreds of other slaves. Angron won this inhuman challenge and shed the last tear he would ever allow himself. Proclaimed as a promising new talent to the arena, he was cast into the pit they kept the gladiators were kept and nursed back to health for the next bout and torture.
As with all of his brothers, he grew at an accelerated rate and to a fearsome size. He became a firm favorite known as the 'lord of the red sands', unbeaten in any bouts. He formed an incredibly strong sense of honour and bond with the other gladiators he had been adopted in a way by an older, more experienced gladiator named Oenomaus. They would become a duo that would conquer any put before them, but never with malice or in a way to prolong the pain. Angron would always spare those who fought well. A tradition of the gladiators was to form a victory rope of there own bodies, they would cut themselves deep enough to scar, if they had won it would be left to heal clean but if it was a loss then they would rub dust from the area unto it so it healed red, Angron had the only completely clean rope of all the other gladiators, proving his superiority. The Primarch never accepted his slavery; he would repeatedly try to escape but never succeeded. His unbroken spirit would constantly test his captors; maybe this led to what happened next, an attempt at humbling the unconquerable spirit of Angron.
The unstoppable pair were thrown into combat against two fearsome Ogryn that had suffered the Butcher's Nails treatment, in a thrilling battle, the pair won a well fought victory, but the High-Riders were not satisfied with that they demanded that straight after that fight that the adoptive father and son duo fight to the death, Angron refused and with his already fiery temper flaring openly insulted his masters as a result he was made a example of by forcing him to be implanted with the nails. Shortly after he healed from the surgery, he was sent again against his father figure, but this time, he tore him apart with a whirlwind of berserk fury. Once Angron realised what he had done, he dropped to his knees and let loose a howl of pure anguish that lasted for days. This would prove to be the final injustice he would accept from the High-Riders, and he swore their destruction would come by his hands. Angron began to train his fellow captives; they became supremely skilled at his instruction, and no other Gladiator arena could stand against them. Within the period of a few years this took Angron also learned, he learned that he would never succeed in escaping by himself; he needed to use the influence his abilities had garnered with his fellow gladiators. Their chance came eventually, the event was to be the largest death games ever to take place, in it Angron was allowed to stage an event including every gladiator, at their first opportunity, they turned on the armed guards a slaughtered them at a very high rate of attrition, just under 2000 escaped, fleeing into the mountains where Angron's story had begun.
The small band of escapees was hunted time and time again over the next few years, but managed to fight for their freedom. It took its toll by this time; there were barely 1000 left. They had named themselves the Eaters of Cities. It all finally came to a head on the mountain Fedan Mhor at the north of Nuceria; they were surrounded by 7 large armies sent to destroy them completely. As fate would have it, the Emperor of Mankind had entered the orbit of the planet months before and had been watching his son with pride as he led his loyal band of brothers and sisters. But he would not allow the Primarch to be wasted in a hopeless battle. The Emperor and a small honour guard of Custodes teleported down to the surface to claim Angron for his larger destiny. He explained the reasons behind the Primarchs' creation and offered him the role as Primarch of the War Hound Legion, made from his genetic material. Angron refused and chose to die with his Chosen family. The emperor, in disbelief, gave the order to teleport the Primarch back to his flagship, forcing him to abandon his troops before the pivotal battle that would result in their complete destruction. For years after the High-Riders would claim that Angron ran from this battle like a coward and hid in fear somewhere in the wilds, until the time Angron would return with his legion after their fall to Chaos, destroying the planet and using it as a catalyst for his ascension to a Daemon Primarch. Angron would never forgive the Emperor for this act and would forever claim his legion was nothing compared to his chosen war-band of fellow gladiators.

Corvus Corax Primarch of the 19th legion Raven Guard.
The moon of Lycaeus was a forced labour prison mine to provide the ore to the nearby forge world of Kiavahr. Ran by the Tech guilds, the prisoners were a mix of the worst of criminals to the people who, for some reason, couldn't fulfill the daily quotas wanted from them elsewhere. To be exiled to the moon was an effective death sentence; the brutal enforcers and guards, or the working conditions, would kill most prisoners before their time. it was into this bleak, dark existence that the Primarch Corvus Corax would find himself thrown. Beneath the surface of the moon, in a dark and empty chamber, the young Primarch was found just after he gained consciousness, which in itself was a work of fate as the miners just happened to be close by following a seam of minerals. The slaves decided to hide the child from the overseers; these sadistic guards were known to be extremely cruel and used whips liberally. Seeing the Primarchs' rapid maturation, the Slaves took it as a sign he was there for a special reason and named him saviour or deliverer in their language. Although the Emperor had gifted within their very genes instinctual knowledge, Corax had to learn from those who had taken him in and hid him. He was all fire and wanted to take the fight to their oppressors directly, this would have ended with him being killed for even a Primarch can not fight a whole moon of heavily armed guards by himself with no weapons or armour, if this had of happened the Imperium would have lost a great champion for the downtrodden and it would have been a darker place.
Instead, he was cautioned to be patient and to observe his quarry, find their weaknesses, and to strike from the shadows on the battlefields of his choice. something that the Raven Guard would go on to do in great effect. During this period of observation, Corax learned of a unique ability he had been graced with: when in the direct sight of an enemy, he could choose to be seen or not, able to move completely unseen in their direct view. As with everything, there were limits to this ability; auspexes and other artificial means of detection were not fooled; it seemed to only affect the mind of the observer, not actual traditional invisibility. Once the primarch reached maturity and his observations and intelligence gathering were complete, he waged a war of sabotage and theft to gain the items needed for full warfare. The systems affected would only fail at the time of his choosing, and that was soon coming. When that moment came, it was a war with a high cost, although necessary, mainly because not only were the unjustly imprisoned released, the killers and other hardened criminals were also set free with the warning never to repeat their crimes or face his wrath. Again, as fate would have it, it was just after the prison was broken open and the beginning missiles of the nuclear bombardment of Kiavahr had begun that the Emperor came for his son. Without fanfare or any accompanying Custodes, the Emperor met with Corax it is unknown what they spoke of; all that is known is that the Emperor left Corax to complete his earlier oath to the prisoners, then he would be free to join his legion.
Unknown - all information obliterated from imperial record - 11th legion.
Alpharius Omegon Primarch of the 20th legion Alpha legion.
Of all the Primarchs, the least is known about the Alpha Legion's Primarch. One Imperial record states that the Primarch was found by accident by a Luna Wolves detachment. He was the leader of a star system and managed by trickery to destroy a cruiser, which Horus came to answer. In which ambush after ambush plagued them until the mighty Vengeful Spirit flagship came under attack. During this ambush, a single fighter made his way to the command chamber after killing the Justaerin bodyguards. Horus himself was attacked as he realised he was facing a brother and not a simple commander. Alpharius agreed to lead the worlds into the Imperium but denied that any were his home planet and would say no further at all.
A second account found much later by Imperial agents, ripping it from the mind of an Alpha Legion centurion captured by the Custodes. Speaking of a Dead World lost to time and war, an ancient alien race civilisation rose and died before humanity's first steps upon Terra, upon this lost world, which was where the Primarch found himself castaway. Alone and against the elements and with just the ghosts of a long-lost alien race for company, he was forced to survive by his wits and the gifts of his creation. After many years, a pirate ship intent on plundering the ruins came to the planet and was instead slaughtered by the Primarch. From here, he set out to find his path in the universe and hopefully find who had created him and why.
There are many more accounts, each more and more fantastic and stranger than the other. Perhaps they all contain a bit of the truth, like all good lies; perhaps they are all false, and the truth is still out there to find. The persistent statement that appears in some form in multiple places is that it wasn't just a singular Primarch, but because of the warp rift that snatched them away from Terra, there was actually a twin Primarch formed and kept as a secret for the Primarchs to fulfill a secret mission given by the Emperor. The nature of secret keeping became ingrained into the Alpha legion, and it has proven to be one of the best kept secrets of the Astartes.