Almuric by Robert E. Howard

Much I learned of the ways of that terrible people, who have reigned over Almuric since ages beyond the memory of man. They might have been human once, long ago, but I doubt it. I believe they represented a separate branch on the tree of evolution, and that it is only an incredible freak of coincidence which cast them in a mold so similar to man, instead of the shapes of the abysmal, howling, blasphemous dwellers of Outer Darkness.

In many ways they seemed, superficially, human enough, but if one followed their lines of consciousness far enough, he would come upon phases inexplicable and alien to humanity. As far as pure intellect went, they were superior to the hairy Guras. But they lacked altogether the decency, honesty, courage, and general manliness of the apemen. The Guras were quick to wrath, savage and brutal in their anger; but there was a studied cruelty about the Yagas which made the others seem like mere rough children. The Yagas were merciless in their calmest moments; roused to anger, their excesses were horrible to behold.