13th Black Crusade - The Screaming Pit: In the wake of the Archangels' destruction of Ioline, the war for the Diamor System entered its finale. Within solar hours of the Hex Infernium's destruction, word reached the Imperial leadership of combat escalating across the star system. Meanwhile, Chaos ground forces moved to strike the killing blow. The time had come for victory, or death. Stirred to action by the destruction of Ioline, the Black Legion struck at Amethal directly. They concentrated their full force upon Hub Beta-Secundus, and the dark prize that lurked there. The Imperial forces had gathered to form a great noose, marshalling their strength before they struck the last blow to eradicate the Chaos threat once and for all. The plan belonged to Captain Aphael, whose own forces formed the southernmost element of the offensive. As one, the armies of the Imperium advanced across the burned-out kill zone that the Mechanicus had cleared so many solar weeks before. They charged into the blizzard of fire hurled from on high by the warships of the Black Legion. Barrage bombs sailed down to explode with enormous force, sending Knights sprawling and turning squads of Skitarii to ash. Lance beams hammered Titan Void Shields, or atomised squads of Assault Marines. Yet though the bombardment was heavy and the destruction horrific, the Imperial forces did not slacken their pace. While battle raged on the planet below, vast warships duelled in the void high above.The Adepts of the Adeptus Mechanicus understood the true prize that the Black Legion sought upon Amethal, even if few others did. It was the thing that had brought Technoarchaeologist Dominus Ivasnophon and his followers from the Forge World of Metalica to this cursed planet. It was a power of unbelievable magnitude, though the Imperium and the Traitors sought it for very different reasons. Lord Xorphas knew its true nature, for it was he and his cabal who had located it for Abaddon. The Despoiler had set his forces in motion as soon as it had been identified. The battle to come would bear upon the success of the 13th Black Crusade, for it offered an opportunity to extend Abaddon's Crimson Path like a bloody wound across Imperial space. The secret that the Black Legion sought, and that the Adeptus Mechanicus were racing against them to seize, lay deep beneath the surface of Amethal. It was ancient -- unspeakably, unimaginably so. Known as the Banshee Stone, it was a prison the size of a world, forged by godlike beings before Terra had even spawned its first single-celled organisms. It was a cage for the infernal creatures of the Warp, a daemonic weapon to dwarf the Damnation Cache that had slipped through Abaddon's fingers on the world of Pandorax. And, according to the divinations of the Chaos Lord Xorphas and his followers, it was full to the brim with howling daemons. It required only the correct ritual to be broken open, at which point the sudden release of so many Warp entities would tear a gaping wound in reality itself.While battle raged between the Blood Angels and the Black Legion, Xorphas, a potent Black Legion Chaos Sorcerer, arrived at the lip of the War Zone Carnage's main excavation site at Hub Beta-Secundus. Their objective was the "gate" of the primordial daemon cage. Thanks to the Crimson Slaughter, Lord Xorphas knew where the cage's wards were weakest, and where its inmates' powers could leak through. Though the Blood Angels fought the Forces of Chaos to a standstill, and looked as if they would achieve inevitable victory, the heroes of the Blood Angels felt a terrible sense that they had been manoeuvred into attacking too late. With their foes gone, the red-armoured warriors rushed down the earth ramp and into the flickering depths of the excavation site. There they faced the screaming horror of the Chaos artefact known as the Banshee Stone, a twisted crystal the size of a boarding torpedo around which blood was welling through the cracking bedrock in lapping tides.Though the ritual was not yet complete, Lord Xorphas realised that he was out of time. This would not be another Pandorax, however. The Banshee Stone had reached a terrible pitch of disharmony, and massive damage had been wrought upon the arcane wards that held the daemon cage closed. It might not rupture immediately, but it would not last long. With a booming psychic command, the Sorcerer ordered the retreat. Abandoning the Banshee Stone to run on for as long as it could, Xorphas and his cabal stormed up the ramp that led out of the pit. Accompanied by black-armoured Terminators, the Sorcerer and his acolytes unleashed the full fury of their psychic might to drive back the Blood Angels who rushed to meet them. With breathing space secured and a clear teleport lock established, the Black Legion was whisked away in a blaze of Warplight, leaving its foes raging in its wake. On the planet's surface the slaughter continued for many solar hours before the last of the Traitor forces were destroyed. Only by the combined efforts of Librarian Asmasael and his psychically-attuned brothers was the Banshee Stone's hideous lament silenced. By that time, the Traitor fleet had scattered, making for predetermined retreat coordinates.The Blood Angels than extracted their forces from Amethal's surface. In the solar hours that followed, a roiling blast wave swept across the planet's surface, obliterating all trace of Chaotic industry on the planet, and leaving nothing but blackened, glowing ash in its wake. It took seven solar days before the fury of the global firestorms burned down to fume and smoke, by which time the planet was little more than a ravaged shell. The destruction was unimaginable, but the Blood Angels had their victory, and had dealt Xorphas' forces a dire blow. Of the Sanguinor, there was no sign. Karlaen himself had seen him escape the destruction of Ioline, a streak of gold soaring away into the heavens. When the hour was once again dark enough, he would return to aid his brothers.The Imperium believed that they had won a great victory on Amethal, that they had foiled the Despoiler's plans once again. But Librarian Asmasael realised that the enemy had done more damage to the Banshee Stone than the Blood Angels had first realised. Perhaps defeat on Amethal had not been avoided, but merely delayed. Unknown to the Imperial forces, already, the cracks in the crystal that served as a daemonic cage had spread beyond repair, even had anyone living known how to fix them. The energies of the Banshee Stone were no longer needed -- it was just a matter of time before the Sorcerer Xorphas and his followers completed their diabolical task. The bars of the daemon cage would break--it was only a matter of time. As they gathered their forces to depart the system and return to Baal, the Blood Angels left behind Librarian Asmasael and a squad of 10th Company Scouts. These Blood Angels would remain on Amethal, attempting to gauge the true extent of the damage done, and standing watch if -- when -- the prison of the Banshee Stone threatened to break asunder.