Dirthiss was a Terran Dominion scientist working at Garxxax Base on the planet Garxxax. In 2501, the biospheres on the base went offline due to a zerg attack, and the order was given to evacuate the scientists. When the scientists were ordered to meet in the central lobby of their base, Dirthiss was packing in his dorm. The zerg surrounded the base, and killed all of the scientists within.