The Yangs were the Yankees of Omega IV. They were engaged for many years in conflict with the Kohms. The Yangs held an American flag and a copy of the Constitution of the United States of America as sacred items and words handed down by God. When James T. Kirk corrected their 'sacred words' they seemed unaware that any other culture knew American history.

It was unknown if the Yangs were from 20th century Earth, or had evolved in the exact same way as Humans. (TOS episode: "The Omega Glory")