Tsagualsa

Tsagualsa, or the Carrion World, is a Dead World located on the farthest fringes of Segmentum Ultima, on the fringes of Imperial space. It is a cold, arid, and inhospitable world, notable mainly for the fact that it became the de facto homeworld of the Night Lords after Konrad Curze ordered the destruction of Nostramo prior to the Horus Heresy.

During the Thramas Crusade, Curze and the Night Lords found themselves faced with the main strength of the Dark Angels led by a very pissed-off Lion El'Jonson. After two years of stalemate, Curze called for a parley with the Lion, designating Tsagualsa as the meeting place. Secretly, Curze planned to use the meeting to break the Lion either physically or mentally, preferably both. The two primarchs, each escorted by two members of their honor guard--Corswain and Alajos for the Lion, Sevatar and Sheng for Curze--met upon Tsagualsa's surface. The meeting went surprisingly well at first, until Curze decided to start the whole "Lion is a closet traitor" meme and the Lion indicated that he disagreed by jamming his sword through Curze's chest. After a short but nasty fight, the two primarchs were dragged off each other while screaming insults, and the Thramas conflict reignited in earnest.

After the Horus Heresy was ended, Konrad Curze returned to Tsagualsa after escaping from the stasis coffin that Sanguinius had stuffed him into. There, he waited for his legion to return. The first arrivals were Talos Valcoran and the members of his squad, followed shortly by much of the VIII Legion, which had largely scattered after Curze and Sevatar's disappearances. The Night Lords turned Tsagualsa into their base of operations, building a palace for Curze that was made from living bodies, with a grand hallway carpeted with screaming faces and a throne of fused bone taken from Curze's many victims. Here, Curze and his Night Lords met to plan new operations against the Imperium and revel in the tortures and horrors they were able to inflict. Eventually, the Callidus Assassin M'Shen arrived on Tsagualsa and executed Curze. This was followed by a full-scale assault on the planet by the Ultramarines and all of their successor chapters, which drove the Night Lords off and led to the VIII Legion's permanent disbandment. After this, the world lay dead and forgotten for millennia.

In the 41st Millennium, a group of Imperial colonists, cut off by a warp storm, stumbled across Tsagualsa. They settled the planet, naming it Darchana. As it was beyond the light of the Astronomican, it was considered not to be an Imperial world; though the Imperium acknowledged the colony's existence, they neither claimed it nor offered any support to the colonists. The population slowly collapsed, and was then erased entirely when some of the Night Lords rocked up to their old crib to reclaim it. They massacred nearly the entire populace, then channeled their pain and agony into the minds of the colony's astropaths, creating a massive Warp-shockwave that killed thousands of astropaths along a line, blinding and deafening a large segment of the Imperium. It remains unknown whether the Night Lords stayed on Tsagualsa, but given their usual hit-and-run tactics, it seems unlikely.