Pek was a Klingon member of Klahb, and in 2379 participated in the attempted takeover of the Federation Embassy on Qo'noS. He was hired as a kitchen steward at the embassy sometime in the month prior to the takeover.
During the takeover, while Worf was attempting to climb the turboshaft in the embassy, Pek and Larq surprised him and were able to paralyze one of his arms with a shot from their Breen disruptors. Worf jumped at them and attacked, and when Pek bent over to pick up a dropped disruptor, Worf kicked him causing him to fall down the turboshaft to his death. (TNG novel: A Time for War, A Time for Peace)