In the mirror universe, K'mpec was a Klingon male in the service of first the Klingon Empire and then the Klingon-Cardassian Alliance during the 23rd and 24th centuries. Prior to the 2370s, he served as the Regent of the Klingon Empire. During his tenure, he signed the Raknal Accords, an agreement among the major Alpha Quadrant powers forbidding the use of trilithium explosives to detonate stars. The treaty was abrogated in 2378 when Regent Klag used such a device to destroy Ferenginar and exterminate the Ferengi. Klag told the Klingon High Council that K'mpec was a weakling and a fool for signing the agreement in the first place. (ST - Mirror Universe novel: Rise Like Lions)