The Horus Heresy was a time of total war, a great schism rent across the Imperium in the wake of the Great Evil one's folly. Horus' trickery and deciet ensnared no less than nine Space Marine Legions, whether by coerion, misdirection or corruption.

The Space Wolves, although not present for many of the final battles when the forces of Chaos laid siege to the Emperor's Palace itself, were heavily involved in the foundations of the Horus Heresy. It was in the disastrous beginnings of this time that the Sons of Russ began theirs ages-long blood feud with the Thousand Sons Space Marine Legion.

In contrast to the Space Wolves, the Thousand Sons Space Marines were fixated with the pursuit of lore and, as a result, much can be gleaned from the tomes recovered since their fall.
Their are even accounts of the ruination of the Legion; most notably the Fall of Prospero, but all are tinged with the bitterness of defeat. Within these rotting texts, the Space Wolves that portrays this time, and the collation of events that appear in both accounts, it is possiable to put together a fairly accurate picture of what truely started the blood feud between these two Legions.

Magnus the Red was a giant of a man, standing fat taller than even his brother Primarchs, his hair and complexion a livid red. Most remarkable of all was the enormooous cyclopean eye set deep into the Primarch's forehead; where normal men have two eyes, Magnus had the one.
His strength was lauded as rivaling that of Russ, but he preferred to expend his energies learning and pursuing ancient arcana than the art of battle. His physical peculiarities were never remarked upon by the other Primarchs; after all, Sanguinius was blessed with wings and Leman Russ himself bore the sharpest of fangs. Nonetheless, the Wolf King feared that the taint of Chaos was ingrained within the giant's soul. But the Emperor would not hear of his suspicions, as Magnus was one of his own sons.

As the events leadong up to the Horus Heresy ripened into terrible fruition, Manus the Red sent a psychic message to the Emperor. No records exist as to what the message was, but more than one source theorizes that it was a warning against the treachery of Horus. Although the message was said to be of great import, it inadvertently revealed the true extent of the practices of the Thousand Sons. The Emperor refused to believe that Horus, his favored son, wold betray him, and he rose in anger against Magnus'warning. As the flame haired Primarch opened a psychic connection to the Emperor, the Emperor was aghast at the extent of the research Magnus had conducted into heretical and blasphemous arts. In the Emperor's eyes, the Thousand Sons had probed to deeply into mysteries better left alone, willinglly walking in the lair of the beast. Magnus' explanations did not pacify the Emperor, and Russ' worst suspicions were confirmed. At Russ' insistence, the Emperor was persuaded that Magnus was the Traitor, not Hours. Horrified, the Emperor commanded Russ to leave immediately for the Thousand Sons' home world. The Wolf King mustered his legions about him, and prepared one more to goto war.

Prospero was once the very image of paradise. Great towers of ice and ivory studed the landscape, and beautiful gardens and peaceful lakes were abundant. Russ beleived that this veneer of civilization and culture hid a roiling foundation of evil. In his eyes, every scholar, scribe, and sorcerer had delved to far into the mire of chaos, had drunk to deeply from the blasphemous waters of forbidden knowledge. There was no option; the Wolf King knew that he must follow the Emperor's command to the letter: cast down the Thousand Sons.

After a lengthy and punishing series of bombardments, the legions of the Wolf King fell upon the inhabitants of Prospero in an acalanche of howling fury. The savagery and ferocity of the Space WOlves' attack enabled them to strike through the heart of Prospero's capital, but the Thousand Sons had prescience enough to prepare their final defenses. By the time the Space Wolves had slaughtered their way to the gates of the largest citadels, the Legions of Magnus the Red were waiting for them.

The ensuing battle raged day and night without pause, the Space Wolves fighting with furious zeal, the Thousand Sons battling for their very home world. By all accounts, although there is little in the way of specifics, the war between the Legions took many days and cost thousand of lives.

Ultimately, for all their wisdom, the Thousand Sons could not stand against the fury of the entire Space Wolves Legion in the field of war. At the forefront of the Space Wolves' battlines, led by Jorin Bloodfang, was the Thirteenth Great Company. They were those who adopted the form of the Wulfen, their bestial souls transforming them into nightmarish hafl-wolves in the heat of battle. The sheer scale of the carnage the Thirteenth Great Company caused opened a massive hole in the lines of the Thousand Sons, and soon the verdant pastures of Prospero ran red with streams of blood. Magnus' brave warriors were slowly but surely culled, their numbers melting under the intense fire of the Space Wolves assault. Although they did not fear for their lives, they fought to their last breath to protect their lore and their home world.

The loss of each and every Space Marine in recorded in Propero's lament, and although its veracity is in question, it remains the only account of the cyclopean Primarch's horrifying bargain.

"Magnus, squatting in his vast tower, watched in agony as his sons were torn to pieces by the babarian Wolves of Russ.. The howls of the pack resounded in his ears, destroying his concentration, breaking his psychic wards and driving him to the edge of madness. Bounding from his ebony throne, he flung his arms in the air and roared a plea for help to save his legion and their geat works. As if something malign had been waiting for the Cyclops' call, the sky grew dark and the air bioled with energy. Magnus was infused with eldritch power, his frame buckling as vile changes were wrought upon his body and his soul. He gazed out from the parapets of his citadel at the landscape of pain stretching before him, and screamed.

Hundres of the Sons of Russ lost their minds completely as the magicks of Magnus took their toll. The skies cracked open, kaleidoscopic lighting blasting apart squad after squad of the savage Space Wolves. The very soil of Propero sprouted ten-fingered hands like obscene fungi, clutching at the legs of the beast-warriors. And yet, they fought on regardless, sheer bloodlust inuring them against the numberous terrors now defending the citadels"

It can be presumed that this tale is continued from the Space Wolves' perspective of the titanic battle between Russ and Magnus, as related by the legend " The War of the Giants," committed to memory by Inquisitor Bastalek Grim (1087345.m4/5586741.P12).

" Magnus the Red took to the field of battl. The ravaged ground liquefied under his mighty strides as he cut a swathe through the ranks of Space Wolves, crushing everything in his path.

Where his gaze fell, even the stoutest Long Fang turned white and died.The single orb in his forehead pulsed with an unatural light, and his red mane stood on end with the energies coursing around him. Truely, this was an abomination in the eyes of the Emperor."

Leman Russ leapt from the thick of the melee to intercpet the rampaging gaint. As he turned, Russ grabbed one of the traitors by the throat and flung it at the giants face. Magnus' petrifying gaze was blocked for a moment, and with celerity unheard of, Russ charged bodily into the crimson behemoth.

And yet he did not fall.

The giant moved far faster than a being of such size might,smashing his fist into Russ'chest with force enough to splinter his breastplate. pushing slivers of cermite into Russ'heart.

But the Wolf King was undaunted. Grabbing the giants arm as Magnus reared back for another blow, Russ was brought near to the gaint's face, and kicked him squarely in the eye. Magnus' roar of pain shattered the sky above, and thick black blood began to rain from the heavens.

Russ took his chance, and grabbed his blinded foe about the waist. Lifting the Cyclops clean off the ground, teeth grinding in a grimace of pain, the Wolf King broke the Cyclop's back. The Thousand Sons, seeing their Primarch brokn and cast down, turned and fled. But as Russ raised the Frostblade Mjalnar to deliver the killing blow, Magnus gasped a word of power and sank into the iridescent ground."

As for the conclusion of this epic battle, the accounts vary wildly. Some sources maintain that the sorcerers of the Thousand Sons opened a gate into the warp, fleeing into the jaws of Chaos rather than face the fury of the Space Wolves. Some claim that as his quarry escaped, Leman Russ swore an oath that he would destroy the legion to a man. Some claim that the traitor Legion became as ghosts, their diabolic patron protecting them from further harm.

But these are certainties about the flight of the Thousand Sons. They were not destroyed, and they salvaged much of their knowledge and arcane literature. Magnus himself was not killed, as he and his minions have plagued the Imperium for thousands of years since that day. Also, however they escaped, the Thirteenth Company, the Wulfen-Kind, were in pursuit. They have vanished from Imperial records since that time. The Space Wolves honor their loss by a blank stone in the Grand Annulus, and the Thirteenth Company has never been replaced.

End of The Horus Heresy, Continues to the The Disappearance of Russ.