Tsagualsa - Horus Heresy: 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.The primarch eventually returned to Nostramo with his Night Lords Legion to fulfill one of his horrific visions. Judging the people of his planet irredeemably 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 in his absence.During the Horus Heresy, two Terran years after the events of the Drop Site Massacre of Isstvan V, the Night Lords and Dark Angels Legions were locked in a bitter struggle over the fate of the Aegis Sub-sector of the Thramas Sector as part of the Thramas Crusade.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 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 -- Corswain and Alajos of the Dark Angels and Sevatar and Sheng of the Night Lords. 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 -- Corswain -- 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 Sub-sector throughout the Thramas Crusade.In the wake of his later capture by Lion El'Jonson and the forces of the Imperium Secundus, Curze was freed from captivity by his brother Sanguinius, ejected from the Blood Angels' flagship Red Tear in a stasis coffin following the Second Battle of Davin. Sanguinius, knowing that he was going to face his destiny at the Siege of Terra, had decided that the Night Haunter should also face his own foreordained doom and so had released him to find it.After several Terran years of drifting through space in the stasis coffin, Curze was eventually recovered and awakened by the crew of the Imperial freighter Sheldroon after the end of the Horus Heresy. After taking control of the vessel, Curze and a sole surviving crewman made their way to Tsagualsa. Upon its surface, Curze waited for several solar days before Talos Valcoran and his 1st Claw arrived. On Curze's orders, the Night Lords proceeded to transform Tsagualsa into their new base of operations.Curze had a grotesque palace built upon its surface, an edifice at first constructed entirely from still-living bodies, though later reinforced with black, bleak stone. Within this fortress 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 the Night Haunter on Tsagualsa and managed to infiltrate his palace, stealing into his throne room. It is believed by most Imperial scholars 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.After the assassination of the Night Lords primarch, the Imperium sought to drive the Night Lords out of Imperial space altogether during the Great Scouring. Although the Ultramarines Legion had been divided into separate Chapters in the Second Founding, all of their Successor Chapters answered the call. Identified among them were the Aurora Chapter, the Praetors of Orpheus, the Novamarines, Genesis Chapter, Silver Eagles and the Black Consuls as well as the Ultramarines themselves. A vessel with the iconography of the Doom Eagles was also seen in the Imperial fleet.Facing such an onslaught, the Night Lords fleet managed to successfully escape from the world but broke up into separate warbands of Heretic Astartes and never operated as a unified Legion again.After being driven from Tsagualsa, some of the Night Lords settled on a new homeworld within the Eye of Terror. This unknown, hellish and perpetually dark planet is a horrific Daemon World where no light ever illuminates the horrible tortures that the Night Lords inflict upon its unfortunate population to fuel their never-ending hunger to experience the fear of others.