Gathalamor is one of the most revered shrine worlds of the Imperium, its surface all but paved over with cathedrals, reliquaries and the endless processions of pilgrims who come to worship the Emperor of Mankind. Its skies are blackened by the smoke of ten billion candles and the incense of unceasing devotion, and its cities exist only to serve the faithful who flock to it from across the stars.
The world's sanctity is ancient and hard-won. In the dark days of a great heresy, the Emperor's will was said to have made itself known here, and the sight of His divine truth broke the power of a mighty traitor whose forces had sought to claim the world. Ever since, Gathalamor has been a bulwark of the Imperial Creed, its Ecclesiarchy shrines guarded by the battle-sisters of the Adepta Sororitas, who suffer no heresy to fester in so holy a place.
Beneath the cathedral-spires lie catacombs vast enough to swallow cities, where the bones of countless martyrs rest in sanctified darkness. Pilgrims descend into these tunnels in search of blessing and never return, and dark things are whispered to stir in the deepest crypts. Yet still the faithful come, drawn by faith across the void, and Gathalamor remains a beacon of devotion in a galaxy drowning in shadow.