Chemos was a world in its death throes long before it became famous. A resource-stripped mining and manufacturing planet cursed with feeble sunlight and endless nights, it had exhausted its own bounty generations before, and its people laboured without cease simply to stave off starvation. Sleep was a luxury and idleness a death sentence, for a world that no longer fed itself demanded every waking hour of toil from those trapped upon it.
Into this slow extinction fell the pod bearing the primarch Fulgrim, discovered by the workers of one struggling settlement. He grew with unnatural speed and brilliance, and as he grew he lifted the failing colony around him, reorganising its labour, reviving its dead industries, and dragging Chemos back from the brink of oblivion through sheer relentless discipline and drive.
By the time the Emperor arrived, Fulgrim had united the whole world and restored it to a fragile prosperity, an achievement born of an ethic that prized striving, craft, and the ceaseless pursuit of a better result. From that ethic of perfectionism came the Emperor's Children, the Legion Fulgrim would lead, whose warriors sought to be flawless in all things.
The Emperor reclaimed His son during the Great Crusade, and Chemos became the homeworld of a Legion obsessed with excellence. Yet the very drive that saved the world would prove the Legion's undoing, for the pursuit of perfection, pushed past all reason, curdled into a hunger for sensation and excess that damned Fulgrim and his sons to Chaos. Chemos itself remains a grim monument to a world that toiled its way back to life, and to the terrible price of a virtue taken too far.