In the mirror universe, the IKS Gorkon was a Klingon Regent-class battle cruiser in the service of the Klingon-Cardassian Alliance during the 24th century. It was named after Regent Gorkon, who led the Alliance to victory over the Terran Republic in 2295.
In 2372, Commander Klag was promoted to captain and placed in command of the vessel by Regent Worf. This surprised Klag, who expected the command to go to Worf's younger brother Captain Kurn. (KE - Mirror Universe short story: "Family Matters")
By 2377, the Gorkon was part of Intendant Kira Nerys' fleet. In January of that year, the Gorkon and the Trager rendezvoused with the IKS Negh'Var where Klag and Gul Akellen Macet met Kira to discuss her plans to defeat the Terran Rebellion using the Klingon 9th Fleet, beginning with an attack on Sindorin. (DS9 novel: Warpath)