The Cavemen are a culture of promitive humanoids that live in Kira, the Cave World of Mongo. Some Cave Men live deeper within the caves while one group, the Cliff Men, led by Zug, live in the cliffside caves of the overworld.Both groups however still are different from the other cave people of the true subterranean regions, the Lizard Men, the Magic Men and the Fire-Men whom the Cliff Men rarely meet and know little about.
("The Caverns of Mongo")