Sanguinius - The Signus Campaign: Solar decades later, Horus exploited this knowledge of the Blood Angels' genetic Flaw. The Warmaster had found a way to sway his "beloved" brother's Legion to his cause and the service of the Chaos Gods -- or see it destroyed before it could become an impediment to his plan to drive on Terra and take the Imperium for his own. It is said that after his turn to Chaos, Horus hated and feared Sanguinius more than any of his brothers and wove many strategies to ensnare or slay him, though all failed. In an effort to weaken and divide the Loyalist forces before he made clear his betrayal, the Warmaster charged the IXth Legion with the arduous task of cleansing the Signus Cluster -- a triple star system of the Segmentum Ultima near the galactic centre.Sanguinius' Legion was ordered to cleanse the 7 worlds and 15 moons of the Signus Cluster of xenos invaders and release the humans settlers from their xenos-overlords. Unaware of the Warmaster's perfidy, Sanguinius willingly obeyed his brother Primarch's commands and immediately set out for this volatile region of space with his Legion. 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 within realspace -- a system of hellish Daemon Worlds under the rule of a Greater Daemon of Slaanesh known as Kyriss the Perverse.When the Blood Angels arrived in-system, their fleet was ambushed by the malevolent forces of the Warp, crippling or killing many of their Navigators and Astropaths in the initial onslaught. The Blood Angels now faced the fury of Chaos for the first time. Kyriss sent an image of himself to Sanguinius, declaring his lordship over the star system in the name of Slaanesh and taunting the Primarch into taking it back from him. Though they had never faced such an unnatural foe, the Blood Angels prepared their counterattack, sure that they would prevail.Rising to the challenge of the vile Greater Daemon, the Blood Angels Legion attacked the daemonic host of Kyriss, launching a series of attacks across the seat of the daemon's power, the world of Signus Prime. Sanguinius faced the vast hordes of human Chaos Cultists and packs of monstrous daemons as an Angel of Vengeance. Soon the planet was awash with the blood of both loyal Space Marines and thousands of slain cultists of Kyriss. The Primarch spearheaded the Blood Angels' assault on the Greater Daemon's seat of power, known as the Cathedral of the Mark, to confront and destroy Kyriss and reclaim the planet in the name of the Emperor. But soon Sanguinius came face-to-face with a new nightmare known as Ka'Bandha, a Greater Daemon of Khorne. Within the pantheon of the Blood God, Ka'Bandha is still regarded as one of his most prolific killers. He was and is a murderous engine of destruction, slaughtering in exalted joy for his lord Khorne.The mighty daemon taunted the Primarch, and revealed Horus' treachery and determination to betray the Emperor. Enraged by the daemon's mockery and fearing his claims about the Warmaster to be true, the angelic Primarch fought the brutal Bloodthirster in single combat. Seizing the initiative during the battle, he surprised the Bloodthirster with his frenzied assault, stabbing his sword into the daemon's chest, ripping open a gaping wound. The massive creature roared in fury and pain, lashing out with his whip at the Primarch's legs.Sanguinius was momentarily unbalanced as his legs were crushed in the whip's coils. The daemon then smashed Sanguinius to the ground with the flat of his massive axe. The winged hero was stunned, helpless before the daemon's wrath. As his vision cleared he looked up at the mighty monster towering over him. The Greater Daemon taunted him one final time, let out a mighty bellow and then struck out across the battlefield, slaughtering 500 Space Marines with huge swathes of his mighty axe. The psychic backlash of the deaths of so many of his Astartes blasted Sanguinius into unconsciousness.It would not be until the closing days of the Horus Heresy that Sanguinius would once again be confronted by the savage Daemon Lord during the Battle of Terra. With the fall of their Primarch and the slaughtering of their brethren, the Blood Angels Legion was consumed by the first onset of what was later known as the "Black Rage" that drove them into a berserker's fury as they charged into the daemonic horde. In their madness they smashed the daemons asunder. Yet the brutal violence of the daemon Ka'Bandha had unleashed something dark within the psyche of the Space Marines, a thirst for blood that would not be slaked until every taint of Chaos had been erased from the planet.Even the mighty Kyriss was ultimately banished back to the Immaterium by his death at the Blood Angels' hands. Only when the planet was cleansed did the rage of the Blood Angels finally subside. Though Signus Prime had been freed from its thrall to the Forces of Chaos, the cost of that victory was far higher than any could have wished. The berserker rage the Blood Angels had experienced had left a brooding shadow on their souls that would manifest in the centuries to come as the great curse that would afflict the Blood Angels and their Successors.Within a few solar days the grievous wounds that Sanguinius had suffered at the hands of the Greater Daemon healed as a result of his accelerated metabolism and superhuman immune system. Whatever befell him in the future, the Primarch swore that he would have his vengeance upon the daemon Ka'bandha. When the call from Rogal Dorn came for the IXth Legion to return to Terra and aid in its defence against the Traitors, the Blood Angels made all haste, as he now understood better than most the gravity of the situation facing the Imperium.