Mukk was a Klingon member of Klahb, and in 2379 participated in the attempted takeover of the Federation Embassy on Qo'noS.
After Worf contacted Rov demanding his surrender, Rov told Karra to take Krant and Mukk with her to attempt to stop Worf from reaching the main computer in the sub-basement. However, they did not get there in time as Worf was able to regain control of the security system and flood the building with anesthizine gas knocking everyone unconscious. Along with all of the surviving members of Klahb except for Rov, Mukk was captured and held by the Klingon authorities. (TNG novel: A Time for War, A Time for Peace)