Tsagualsa, also sometimes referred to as the Carrion World, was a planet located on the Eastern Fringe of the galaxy that the Primarch Konrad Curze of the Night Lords Traitor Legion chose as his base of operations following the destruction of his homeworld Nostramo. After the Night Haunter's Assassination, the world was abandoned by the Night Lords for a new home within the Eye of Terror sometime in the 32nd Millennium.
Just before the Horus Heresy erupted, Konrad Curze had been constantly plagued by prophetic visions of the future that haunted him. Following his long absence during the Great Crusade, the Night Haunter's homeworld of Nostramo had degenerated once more into the anarchy and corruption that was its natural state. He eventually returned to Nostramo with his Night Lords Legion to fulfill one of his horrific visions. Judging his planet guilty, the Night Haunter ordered the orbiting Night Lords fleet to destroy the dark world utterly with orbital fire from his fleet. This was Nostramo's punishment for its people's return to their criminal ways.
During the Horus Heresy, two years after the events of the Drop Site Massacre of Istvaan V, the Night Lords and Dark Angels Legions were locked in a bitter struggle over the fate of the Aegis Subsector. Neither side was able to break the stalemate, so in an audacious attempt to claim victory, the Night Haunter invited his brother Primarch Lion El'Jonson to a parley on the barren world of Tsagualsa. Night Haunter wanted to break his former brother either mentally, physically or both to obtain his objectives. The Primarchs were accompanied by two warriors from their personal Honour Guards to the parley. The meeting began amicably enough between the two Primarchs as they conversed with relative civility towards one another. This amity lasted until the Night Haunter slandered El'Jonson, and in return the Lion struck his former brother. This further degenerated into an all-out brawl between the two sides. As the Night Haunter strangled the life out of El'Jonson, one of the Dark Angels Honour Guardsmen ran his sword through the Night Haunter's back, saving his Primarch's life. Eventually both Legions sent reinforcements in response to this incident. Each side dragged away their respective Primarchs from the scene of the combat. Both Primarchs survived this brutal confrontation and went on to continue the contest between their Legions for control of the Aegis Subsector.
After the destruction of Nostramo, the Night Lords Legion found themselves without a world to call their own. Eventually, the Night Haunter decided to take the world of Tsagualsa as his new base of operations. He had a grotesque palace built upon its surface, an edifice constructed entirely from still-living bodies. Within his palace of flesh and bone Curze had a morbid carpet made of living faces that eternally screamed, which led past a pool of deepest shadow to the Night Haunter's throne room where he sat upon a throne made from the fused human bones of his many victims. This corridor was known as the Screaming Gallery. The Captains of the Night Lords would often join their Primarch within these dark chambers to plot and revel in the fear and agony they caused. From this new base of operations the Night Haunter's dark hand was still evident in the brutal acts of wanton murder and destruction committed by his Legion across the Imperium in the years immediately after the end of the Horus Heresy.
During this time, the Emperor of Mankind had issued the order for the life of the Night Haunter to be terminated at the hands of what eventually became the Callidus Temple of the Officio Assassinorum. Fully half of the existing Callidus Clade operatives were dispatched to locate and destroy the Night Lords' Primarch. Eventually, the Callidus Assassin M'Shen located Night Haunter on Tsagualsa and managed to infiltrate his palace, stealing into his throne room. It is believed by most Imperial savants that M'Shen was allowed by Curze to infiltrate his palace, as the Assassin strangely encountered no guards between herself and Night Haunter's throne room. Despite Night Haunter's formidable powers of foresight which had already forewarned him of the assassination attempt, he took no extra precautions to defend himself. When confronted by the Callidus Assassin the Primarch allowed himself to be killed to "vindicate" his decisions to destroy his homeworld of Nostramo and to rebel against the Emperor, since the Emperor had seen fit to deploy the same tactics against him in order to safeguard his realm. In a twisted way, Curze saw himself as a martyr to the cause of true justice.
The Night Lords Legion eventually abandoned Tsagualsa at an unrecorded time in the 32nd Millennium, and settled on a new homeworld within the Eye of Terror. This hellish, perpetually dark planet is a horrific Daemon World where no light ever illuminates the horrible tortures that the Night Lords Chaos Space Marines inflict upon its unfortunate population to fuel their never-ending hunger to experience the fear of others.
Tsagualsa was resettled by Imperial colonists in the 41st Millennium, driven there by a Warp Storm. The nearly-dead world, with its cold temperatures and frequent silica dust storms, was not a hospitable one, and the new colony's position beyond the light of the Astronomican meant the Imperium had left them to live or die on their own. The population halved in five hundred standard years, and then it was ended entirely when the Night Lords returned to try to reuse the world as a base. They butchered millions of colonists, leaving roughly one in every ten thousand alive, and used their hideous Warp-knowledge to inflict the death-trauma of those millions on the colony's Astropaths. Then, these Astropaths' own death-trauma was used to psychically assault Astropaths down an Imperial communication line. The true cause of this event would remain unknown to the Imperium.
- Age of Darkness (Anthology) edited by Christian Dunn, "Savage Weapons" by Aaron Dembski-Bowden
- Index Astartes II, "Bringers of Darkness - The Night Lords Space Marine Legion," pp. 20-27
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