A planet whose people live in a long-running war between Yangs and Kohms, a strange parallel to Earth's past.
Omega IV is a world inhabited by two peoples, the Yangs and the Kohms, whose names and history mirror the Yankees and Communists of Earth. Their war devastated the planet long ago, and the survivors developed resistance to disease that gives them extremely long lives.
In The Omega Glory, Kirk finds the USS Exeter's crew dead from a disease and its captain, Ronald Tracey, on the surface aiding the Kohms with phasers in a search for the secret of long life. The Yangs overrun the Kohms, and Kirk restores their understanding of their sacred documents.