In 2268, he was the leader of the Yangs, the guardian of the Holies, and the speaker of the Holy Words (a version of the United States Constitution). The Yangs were at war with the Kohms, who were being helped by Captain Ronald Tracey in violation of the Prime Directive.
After attempting to kill Enterprise Captain James T. Kirk when they were imprisoned together, Cloud William escaped and led a successful Yang attack on the last Kohm village. After he had accepted that Kirk and not Tracey was telling the truth about their origin, Kirk informed him about the true meaning of the Constitution with its values of liberty and freedom applied to all people. Cloud William did not fully understand, but swore to follow Kirk's words and began studying the documents together with his people.