Canis Helix

The Canis Helix, also known as the Spirit of the Wolf, is the name given to the particular genetic sequence of the Space Wolves Space Marine Chapter's gene-seed that endows them with their unusual feral traits. The Canis Helix is derived from a unique segment of the genome of the Chapter's Primarch Leman Russ and is actually a genetic catalyst imbibed by the Chapter's Aspirants to begin their physical transformation into superhuman Astartes. However, the Canis Helix is unstable and can reduce a Space Wolves Astartes into a feral, lupine mutant known as a Wulfen at nearly any point during his service to the Emperor of Mankind. It is keeping control of himself and refusing to give into the savage demands of what the people of Fenris have come to call the Curse of the Wulfen, that defines what it means to be a Space Wolves Astartes.

History
The massive scientific effort to create the Primarchs after the end of the Unification Wars in the 30th Millennium was known as the Primarch Project. The means by which the Emperor crafted 20 individual superhuman genomes using his own arcane genetic code as the base without resorting to the use of cloning is unknown to present Imperial science. There was a 2-stage process involved: first, the Emperor extracted a subset of his own DNA to act as the foundation for a pure, undifferentiated Primarch gene-stock. The pure Primarch gene-stock was then further differentiated into the 20 strands that would serve as the individual Primarchs' genomes. The data concerning the original engineering of the individual Primarch strands was later analyzed by a Raven Guard Apothecary and a Magos Genetor of the Adeptus Mechanicus during the Horus Heresy. They discovered that certain samples had gene sequences deliberately deleted from the base Primarch genome, while other samples showed the addition of clearly non-human DNA. Intriguingly, the genome of the Primarch listed as "Subject VI" had added canine-like DNA. Although it is not clear whether the sample numbers corresponded to the actual Primarchs of the numbered Space Marine Legions, this could explain the wolf-like affinity of Leman Russ and the unexpected feral mutation of many Space WolvesAstartes into the Wulfen.

When a Space Wolves Aspirant is deemed worthy to join the Chapter, he partakes in a sacred ceremony where he imbibes the Canis Helix, the Spirit of the Wolf. In actuality, this is a genetic cocktail drawn from the genome of Leman Russ and used as a catalyst to activate the genetically-engineered viral machinery of the Aspirant's gene-seed implants, similar to Blood Angels Aspirants who drink the sacred blood of their Primarch Sanguinius from the Red Grail to begin their transformation into Space Marines. This mixture is drunk from an ancient relic of the Space Wolves known as the Cup of Wulfen.

Ancient legends speak of the coming of the Emperor of Mankind to the world of Fenris during the Great Crusade, seeking his long-lost genetic progeny. Many of those that were to become the first Space Wolves were all old men by the standards of the Astartes, having been reavers and sword-brothers to Leman, King of the Rus, for many years before the Allfather had come to Fenris. When the truth of Leman’s heritage was finally revealed, every warrior in the king’s mead-hall had drawn their iron blades and clamoured to fight at his side, as sword-brothers ought. But they were all too old, the Allfather told them; not a man among them was younger than twenty Terran years. The trials they would have to endure would very likely kill them, no matter how courageous and strong-willed they were. Yet the men of Leman’s mead-hall were mighty warriors, each man a hero in his own right, and they would not be dissuaded by thoughts of suffering or death. Leman, the king, was moved by their devotion, and could not find it in his heart to refuse them.

It is said that Leman Russ possessed the Cup of Wulfen, giving this vessel to his original followers, the first men from Fenris to join the ranks of the VI Legion, and told them to drink from the Cup. Amongst the chosen was a jarl named Wulfen. He was a mighty man, fell and strong, proud in his power. He was a man gifted beyond all others in the art of war and he was bested only once in his life, and that was by Russ, who humbled him before all his people but seeing a worthy warrior had spared him, and offered him a place amongst his warriors. Russ spoke to the assembled men of Fenris and told them of his plan. He offered them power and a vast span of years if they followed him to make war among the stars. They roared their acceptance, and hailed Russ as their chief. He told them that they must drink a potent brew from the great cup and thus would their transformation begin. Wulfen was the first to step forward and he swigged the glorious mead of Russ from the chalice.

But evil lurked still in Wulfen. He was consumed by a secret, gnawing hatred of Russ and he planned to take treacherous revenge upon the man-god. The guardian spirit within the cup saw this the moment Wulfen put it to his lips, and it worked a spell on him, making his outer self match his inner evil. To the horror of those who looked on, the great chieftain changed. He turned into a dreadful thing, half-man, half-wolf and he sprang on Russ with a howl of hatred. But Russ was not dismayed. With one blow, he crushed Wulfen's skull and slew the beast that had been revealed. He looked upon his followers and told them that Wulfen was unworthy, and that this would be the fate of all those who drank from the chalice with evil in their hearts. He told them that those who wished could now depart without drinking. To the Space Wolves' ancestors' credit, no man departed, and all drank and all gained the power that Russ had made their due. And thus began the true Founding of the VI Legion. Those men strode forth to write their names in the history of all the worlds of men, becoming the first Space Wolves to be recruited from Fenris.

Effects
In reality, those Aspirants who are likely to fall prey to the Wulfen mutation inherent within the gene-seed of Leman Russ do not do so after immediately imbibing the Canis Helix mixture, but usually over the weeks and months of training that follow afterwards. After drinking from the Cup of Wulfen, the Aspirants are taken through the Gate of Morkai, a mystic portal deep within The Aett (The Fang), the Space Wolves' massive fortress-monastery, where every Aspirant's mind is picked and probed by the Chapter's psychic Rune Priests (Librarians) for signs of corruption or mental weakness that will make them easy prey for the blandishments of Chaos. One of the most important aspects of this test is that the Aspirant show himself able to keep this bestial side under control, even while making his way through the Fenrisian wilderness in harsh conditions. Those that fail to do so will transform into Wulfen, and remain in the wild. If the Aspirant returns to The Fang from this Test of Morkai, he is implanted with the remaining components of the Space Wolves' gene-seed, which stabilise the mutational effects of the Helix. Although this procedure is extremely hazardous, the remaining components of the Space Wolves' gene-seed will prove ineffective at initiating the metamorphosis into an Astartes unless the Canis Helix is implanted first to serve as a catalyst for the transformation.

The next phase of the Neophytes' transformation into a full-fledged Space Wolf is a trial period of training in which the physical transformations initiated by the genetic catalyst within the Canis Helix begin to manifest themselves. Amongst the most common changes are that the Neophyte's senses will become vastly superior to that of other Space Marines, his teeth will lengthen into fangs capable of tearing through Plasteel, and his skin will toughen to the texture of leather. His body mass grows by up to eighty percent and many of his bones fuse. Many of the Aspirants will continue to grow into their newly-received genetic implants whilst others succumb completely to the Curse of the Wolf at this time and devolve into one of the giant, feral and bloodthirsty mutants known as the Wulfen. To become one of these fell creatures is to fall from the Emperor's grace, and to roam the wilderness forevermore as a creature of the darkest night.

The Space Wolves' harsh induction regime generally ensures that these individuals perish at an early stage in the process. However, at the time of the Great Crusade, when the Emperor and his Astartes Legions were conquering vast swathes of the galaxy in the name of Mankind, those brothers touched by the Curse were banded together into the 13th Great Company, where their feral ferocity could be brought to bear en masse, as well as contained for the safety of the whole Legion. But eventually the 13th Company disappeared, their loss the subject of numerous myths.

Even once the Canis Helix gene sequence has been stabilised within the body of a Neophyte, it still has the power to affect the warrior throughout his life, particularly when the ferocity of the Space Wolf, barely contained at the best of times, is roused in battle. Then the warrior may finally succumb to the Curse of the Wulfen, and he will be transformed once again into the beast he has fought for so many centuries to subdue. It falls to the Wolf Priests, the cult leaders and spiritual guides of the Chapter, to keep the Curse of the Wulfen from overtaking the Space Wolves, and they take full responsibility for the development of their charges, be it martially, spiritually or mentally. Those that are "Wolf Bitten" (suffering from the Curse of the Wulfen) are given over to the care of the Wolf Priests.

As Space Wolves Astartes grow older and more experienced in battle, the Canis Helix causes additional physical alterations: their hair turns grey, their fangs grow even longer, their skin becomes even more leathery, and, in some rare cases, their eyes turn yellow. A Space Wolves Astarets who reaches this stage is considered fit for elevation to the rank of Grey Hunter. In some Space Wolves, the Canis Helix leads to the development of a brooding, malignant demeanour, which makes them unfit for the camraderie normal to a Space Wolves Pack (squad). These Astartes traditionally have become Wolf Scouts.

By the time a Space Wolf Astartes is considered fully mature, the Canis Helix has caused their canine teeth to enlongate into true fangs and their hair to grow long, shaggy and grey, at which point they join the ranks of the Long Fangs, the Chapter's Veteran heavy weapon specialists.

It is speculated, though not known for sure, that some latent irregularity in the Canis Helix accounts for the unusual, elemental-based psychic abilities of those Space Wolves who eventually become the Chapter's Rune Priests.