Chang was a Klingon general and chief of staff to Chancellor Gorkon who secretly conspired to wreck the peace talks between the Federation and the Klingon Empire.
Chang was a senior Klingon general and chief of staff to Chancellor Gorkon. A one-eyed veteran warrior with a fondness for quoting Shakespeare, he was openly hostile to the Federation and saw peace as the end of the Klingon way of life.
After the destruction of Praxis pushed Gorkon toward peace, Chang joined a secret alliance of Klingon, Federation and Romulan officers who wanted the old hostilities to continue. The conspirators arranged for torpedoes to appear to be fired from the Enterprise at Kronos One, and Gorkon was murdered. Chang then served as prosecutor at the show trial that sent Kirk and McCoy to the penal colony of Rura Penthe. During the peace conference at Khitomer, he attacked the Enterprise and Excelsior from a prototype Bird-of-Prey that could fire while cloaked, until a modified torpedo tracking his exhaust destroyed his ship.
Chang was the main antagonist of Star Trek VI: The Undiscovered Country, embodying the fear of change that the Khitomer Accords had to overcome.