In the mirror universe, Commander Drex was a Klingon male in the service of the Klingon-Cardassian Alliance during the late 24th century. He was the son of Martok and Sirella. In 2372, Captain Kurn, the commanding officer of the IKS Hegh'ta and the younger brother of Regent Worf, allied himself with Drex in an effort to gain command of the new Regent-class ship IKS Gorkon. When Kurn learned of a betrayal of the Alliance by the House of K'Tal, he tried to turn this to his political advantage. However, Commander Klag of the IKS Pagh also learned of this treachery and, due to his heroic actions to reveal it, was granted command of the Gorkon instead. Kurn, in turn, was given command of the IKS Ya'Vang. Drex became the first officer of the Gorkon.