The abomination of the Whispering Shadows inhabited an eldritch fortress in the Black Kingdoms of the Hyborian Age. The Cimmerian barbarian Conan found himself in a storm and sought shelter in the ruins of a great fortress made of dense black stones which was built with odd angles in the arches, as if the builders weren't quite sane. It had corridors that were like a serpent's track, with some wide and low, and others so narrow that Conan was barely able to pass through.
He could sense and later during his sleep hear the whispers of the ghosts of 1000s of sentients who had died within the fortress and hungered for his blood. While he slept a slaver band of 40 Stygians whom likewise sought shelter from the storm took shelter in the fortress. The ghosts merged and used their lifeforces to create a physical body of numerous malformed heads, limbs, and tentacle-like appendages. It then slaughtered the Stygians, tearing and rending them. While that was happening, Conan fled the citadel.