Upon meeting B'Elanna Torres, who was pregnant, Kohlar believed that she was carrying the kuvah'magh. He destroyed his own ship so that he and his crew could stay aboard Voyager and witness the birth of their savior. Many of Kohlar's crew did not believe that Torres was carrying the kuvah'magh due to her half-Human heritage. A battle ultimately ensued for control of Voyager. When the crew of Voyager prevailed, the Klingons were beamed down to a new planet that would become their home. (VOY: "Prophecy")
Kohlar was played by Wren T. Brown. In an interesting production oddity, Kohlar's hair seemed to change between scenes several times throughout the episode, likely the result of two wigs being used during filming.