Nostramo

Nostramo was a world without a sun's mercy, a lightless planet of black adamantium mines and towering, soot-choked hive-cities where perpetual darkness reigned and no star ever pierced the gloom. Its dense ore made it valuable, but its society was rotten to the core, a place of rampant crime, corruption, and predation where the strong preyed upon the weak and law was a fiction no one believed. Its gangs and syndicates ruled the endless dark, and the weak simply vanished into the mines, never to return.

Into this darkness fell Konrad Curze, who would become the primarch the Nostramans named the Night Haunter. Growing up alone in the murderous underhives, he imposed order the only way the world would understand: through terror. He hunted the criminal and the corrupt without mercy, leaving their flayed remains as warnings, until fear of him alone made Nostramo a place of grim, trembling peace.

When the Emperor came and took Curze to lead the Night Lords, that fragile order died with its enforcer's departure. Without the Haunter to terrify them, the people of Nostramo slid swiftly back into the old corruption, and word of their backsliding reached the primarch among the stars.

His reaction was as monstrous as it was final. Enraged that his home had squandered the order he had bled to impose, Curze commanded his own Chaos Space Marines to turn their guns upon the world, and Nostramo was bombarded until its crust cracked and its hives died screaming. The murder of their own homeworld hardened the VIII Legion into the galaxy's terror-soldiers, warriors who spread fear as a weapon of war. Nostramo is gone now, destroyed not by any enemy but by the very son it had shaped in its own cruel image.