In the mirror universe, Colonel Gowron was a Klingon male in the service of the Klingon-Cardassian Alliance during the 24th century. He was a firm and outspoken opponent to cross-species breeding. As part of this agenda, he sent a Terran slave to assassinate B'Elanna, the half-Klingon, half-Terran Intendant of Ardana, in 2371. The slave was unsuccessful and was himself killed by B'Elanna's personal aide Kate Janeway. (VOY - Mirror Universe novel: The Mirror-Scaled Serpent)
In 2375, his longtime foe Martok succeeded Worf, who had been captured by the Terran Rebellion, as the Regent of the Klingon Empire. Following the victory of Worf's brother Captain Kurn over the rebellion at Empok Nor later that year, Regent Martok assigned Gowron to an Alliance military base on the backwater planet Gamma Pavonis III under the command of General Duras. Gowron was his executive officer, the "very thought of [which] made him spit sour bile."
In 2377, the Memory Omega agent K'Ehleyr infiltrated the base with the intention of killing the traitor Alynna Nechayev to prevent her from revealing the existence of Memory Omega to the Alliance. In the process, K'Ehleyr was captured. Given that she was likewise a Klingon-Terran hybrid, Gowron took great pleasure in torturing her. After beating her severely, he intended to subject her to the Klingon mind sifter. Although K'Ehleyr managed to kill her two guards, Gowron proved to be a worthier opponent. As he was about to slit her throat, he was stabbed from behind through the neck with one of his own d'k tahgs, killing him instantly. K'Ehleyr was surprised to discover that it not her controller Reginald Barclay who had saved her from certain death but Gowron's commanding officer Duras. The general explained that he was an ally of Memory Omega and that he had killed Gowron to prevent him from using the mind sifter on K'Ehleyr. Had he done so, he would have learned of Memory Omega and Duras' efforts to undermine the Alliance would have been for naught. (TNG - Mirror Universe short story: "For Want of a Nail")