Signus Campaign

"If one wishes to go unseen by devils, one should not place their faith in angels."

- Attributed to the Remembrancer Ignace Karkasy M31

The Signus Campaign was a major Imperial campaign conducted at the close of the Great Crusade by the Blood Angels IX Legion to cleanse the Signus Cluster — a triple star system of the Segmentum Ultima near to the galactic centre. Sanguinius' Legion was ordered to cleanse the 7 worlds and 15 moons of Signus of xenos invaders and release the humans thereon from their xenos-overlords. Unaware of Warmaster Horus' perfidy, Sanguinius willingly obeyed his brother Primarch and immediately set out for this volatile region of space. Unbeknownst to the Blood Angels, they were blindly walking into a deadly trap, for the Signus Cluster had fallen prey to agents of the Ruinous Powers and become a veritable Realm of Chaos -- a system of hellish Daemon Worlds under the rule of a Greater Daemon of Slaanesh known as Kyriss the Perverse. Horus hated and feared Sanguinius more than any of his brothers and wove many strategies to ensnare or slay him, though all failed. The Warmaster hoped to turn the Blood Angels' hidden genetic curses, later known as the Black Rage and the Red Thirst, against them in order to enthrall them to the Blood God Khorne and turn yet another Space Marine Legion to his cause. Ultimately, the Warmaster's plan would fail but a darkness would forever after stain the souls of the Blood Angels Legion that would manifest in the centuries to come as the great curse that would afflict them and their Successors.

Dark Secrets
When Warmaster Horus, the greatest of the Emperor's genetic sons, fell to the temptations of the Chaos Gods and became swayed by their promises of power, he sought to sway his brother Primarchs to his cause. Horus and Sanguinius, Primarch of the Blood Angels Legion, had fought many campaigns by each other's side. Their relationship was so close it had even incited jealousy amongst their brother Primarchs on occasion. But in his black heart the Warmaster knew, Sanguinius would never willingly betray their father, and so, he had formulated an audacious plan to either convert the Blood Angels Legions to his cause or utterly destroy them. Many decades earlier, the Warmaster had discovered a carefully guarded secret when he fought alongside Sanguinius' Legion in a xenocide campaign on the world of Melchior.

Horus had come upon his brother Primarch in a sunken ruin of an alien chapel and had witnessed the unthinkable - Sanguinius murdering one of his own Astartes. Sanguinius explained his actions to his bewildered brother. He had discovered that within his own bio-type there was a trait that lay buried and waited to be awakened. During the Great Crusade, this strange affliction had begun to manifest, affecting some of the Blood Angels Legionaries over the course of several decades. The story was always the same -- a warrior of the IX Legion in the throes of battle eventually succumbed to a rage that continued to build and build until his reason was lost. When a Blood Angels Battle-Brother succumbed to this affliction, his humanity would be stripped away until only his feral core remained and all the blood-crazed Astartes wanted to do was kill and kill, satiating himself with blood and more blood. At the end, at the very worst of it, he lost every last piece of himself, until death was a kindness.

Fortunately, only a handful of Astartes had been afflicted over the course of two Terran centuries of continuous conflict. Most would perish in battle without anyone taking note of their growing insanity. But if their degeneration became noticeable, then Sanguinius himself, or the Sanguinary Guard's commander Azkaellon, would usually be the one to end the life of the afflicted Battle-Brother. Yet, in the closing days of the Great Crusade, the outbreaks of this affliction began to occur more often. Sanguinius feared that, in time, this affliction would grow to encompass every member of the IX Legion.

Sanguinius had been aware of the flaw in his genome for several years, keeping the truth from the Emperor and his fellow Primarchs. He could not speak of this to any of the others, for to do so would diminish his Legion in the eyes of his brothers and the Imperium. Some of his brother Primarchs would see it as a weakness and seek to turn this truth against him. Sanguinius was afraid to confide in his father the Emperor for he could not take the risk of being responsible for the erasure of the Blood Angels from Imperial history like the II and XI Legions. He was determined to not see a third empty plinth erected beneath the roof of the Hegemon in the Imperial Palace on Terra as the IX Legion’s only memorial. Sanguinius continued to search for a solution but continued to fail in this endeavour. Some of the Angel’s sons had learned a measure of the truth, but only Azkaellon, First Captain Raldoron, the IX Legion’s Master Apothecary on Baal and a few others were fully aware of the extent of this affliction. They were united with Sanguinius in finding a way of repairing this flaw. Horus swore to his brother that he would never speak of this matter to anyone, even their father. He would keep this promise for as long as Sanguinius wished him to. The Angel was touched by his brother's gesture and expressed his gratitude. The Warmaster solemnly vowed to help Sanguinius deal with this matter, however long it took. Little did they know at the time, that one day, the Warmaster would take full advantage of this knowledge and attempt to turn the Blood Angels' flaws against them.

Sanguinius Betrayed
Using his knowledge of the Blood Angels' genetic flaws, Horus had found a way to sway his 'beloved' brother's Legion to his cause. The Warmaster ordered Sanguinus to gather his entire Legion and make for the Signus Cluster, a system located in the Ultima Segmentum near the Eastern Fringe. His Legion, was to cleanse the 7 worlds and 15 moons of Signus of xenos invaders and release the humans thereon from their xenos-overlords. To further entice Sanguinius, the Warmaster informed him that he had found the means by which the Blood Angels would be able to excise the darkness from within their souls, and rid themselves of their genetic flaws. If Sanguinius obeyed the Warmaster's command in this matter, then Horus promised him that the Blood Angels would find a new freedom. Sanguinius had no reason to doubt Horus, for they were as close as two brothers could be. Many on their fellow Primarchs were even jealous of the closeness between the pair. Sanguinius relished the opportunity to once again prove the value of their bond, and so, the Blood Angels gathered in their entirety and duly set course for the Signus Cluster, unaware that they were heading into the most foul of traps.