Cypher - The Dark Secret: To better understand at least part of the mystery of Cypher, one must first know the tale of the Dark Angels. To outsiders, this is an insurmountable quest, for the Dark Angels Chapter hides its secrets well, masking all activities in a shroud of ritual and clandestine operations. Indeed, even amongst their own Chapter, only the company masters and most distinguished veterans -– the self-styled Inner Circle –- are privy to the truth.In ages past, in the latter years of the Horus Heresy, the Dark Angels homeworld of Caliban was corrupted. The Legion's second-in-command, Luther, betrayed the Dark Angels and turned many of their brethren from the Emperor. These Traitors attacked their primarch, Lion El'Jonson, and the remainder of the Legion upon their return to Caliban.Although the primarch's followers were victorious, the cost was high. Their very homeworld was shattered, their primarch gone and presumed slain. In the death throes of Caliban, the swirling eddies of a Warp Storm opened up –- a perilous gateway to the Realm of Chaos.It was this rent in the fabric of space that consumed the remaining treasonous Dark Angels. It is presumed that Cypher was amidst those heretics swept into the Immaterium. To the great frustration of the Dark Angels, there is no full list or account of who or how many had heeded the dark whispers of the Ruinous Powers and turned against their brothers.The days following the Horus Heresy were the most turbulent of times, for the galaxy-wide empire of Mankind had teetered on the very brink of total collapse. Although Horus was defeated and his remaining followers were on the run, the armies of the Imperium were full of bitterness and recrimination. The unforeseen betrayal of Horus had profound after-effects that are still in existence today.Shorn of the Emperor's guidance, the condemnation of the guilty was totalitarian and egregious, and the Imperium grew ever more repressive. The grim realisation that the Space Marines –- the ultimate warriors of Humankind –- had proven vulnerable to corruption was a severe shock. Fully half of the Space Marine Legions had betrayed the Emperor. If the Dark Angels had admitted that some of their members had turned, their entire Legion would have been condemned.In this paranoid atmosphere, the surviving Dark Angels debated their options even as they paid tribute to their lost primarch. In the end, they felt there was no choice but to hide the truth of their brothers' betrayal. It was decreed by the most senior members of the Legion that no outsider must learn the dreadful truth -- none must know that members of the Dark Angels had proven as corruptible as any mortals and turned to the Ruinous Powers.In the wake of the Fall of Caliban, there was much to do, and many secrets to keep. The Dark Angels found that it was easier to avoid the barrage of questions by fully immersing themselves in rigorous duty. However, they were eventually forced to explain the loss of their primarch and their homeworld of Caliban over and over again, telling their fabricated tale to the High Lords of Terra, and eventually the newly established Inquisition.As no fighting formation carried the war against the rebels forward with more furious resolve than the Dark Angels, no one pressed the grieving warriors too closely. The sons of the Lion continued the fight, chasing the remnants of Horus' armies into the Eye of Terror and enacting many savage acts of revenge. Meanwhile, the largest chunk of what remained of shattered Caliban was chosen as the new headquarters for the Dark Angels. In time, The Rock, as it came to be known, was outfitted with Warp engines, allowing its reach to span the galaxy.It was at first believed that all their traitorous brethren had been destroyed at the Fall of Caliban, yet it was not so. Eventually, the Dark Angels Librarians picked up the telltale traces of their lost brethren. Thus it was revealed that those defeated Dark Angels Traitors -– known as the Fallen Angels, or just the Fallen –- were not all destroyed when they were sucked into the Warp. Instead, the Fallen had been cast across time and space, for the Librarians picked up evidence that many of the Traitors had returned, their psychic signatures shining out briefly from many scattered places across the galaxy.At this point, the Dark Angels merely classified all the Fallen together, for they had not yet recognised or picked out the most mysterious and prolific of their number: the one known as Cypher. That the Traitors escaped their loyal brethren's vengeance was a torment for the surviving Dark Angels.As long as the Fallen lived, the Legion's great shame would live on as well. They might spread knowledge of the Dark Angels' treachery. Any who encountered the Fallen would bear witness not only to the original betrayal, but also the Legion's ensuing cover-up.