In the mirror universe, Klag, son of M'Raq was a Klingon male who served the Klingon-Cardassian Alliance during the 24th century. He had a younger brother, Dorrek. Their father M'Raq had died by 2372. In 2372, he held the rank of commander and was the first officer of the IKS Pagh under the command of Captain Kargan. He and his brother had a bet regarding which of them would be the first son of M'Raq to be promoted to captain and be placed in command of a warship.