Obsidian natives were a humanoid species native to the planet Obsidian. They were distinguished by their dark-olive complexions, sharp features, and angular bodies. Two distinct cultures existed among the Obsidian people: the city dwellers, who took permanent refuge from the desert in the oasis settlement of Kalara; and the nomadic tribes, who roamed the deserts and mountain ranges. The two groups maintained little contact, with the city dwellers considering the nomads uncivilized animals, and the nomads called the residents of Kalara "Tamed Ones", ignorant of the ways of desert life.
One aspect of desert life was the concept of the Sunstorm Truce. During solar storms, all hostilities between tribes were put aside, and no person could be refused shelter from the sun's deadly output.
Obsidian natives had very basic theological beliefs, with a personified force of Good, and an opposite force of Evil: the Fiery One, who is depicted with red hair and eyes of flame. (TOS novel: Vulcan's Forge)