The Brylukas are a pre-human people who lived in the tunnels and in the cave where the Yuetshi used to hide their food. Monstrous in appearance, they are like humanoid bats with white hairless skin, an aberration of nature living on earth when humanity had just appeared. They were locked in the cave by a powerful shaman from an ancestor people of the Yuetshi of the Hyborian age, who placed them under a spell that kept the creatures locked in their stone tombs as long as the great fire in the middle of the cave remained lit.
During the fight between Conan's pirate crew and Artaban's Hyrkanians, the fire was accidentally put out and the monstrous creatures were able to come out and attack both sides. These beings are neither humans, nor beasts, nor demons, but rather a mixture of the three.

Map of the Hyborian age :