Breniss Ox was an ace pilot in the Zeon army nicknamed the "One-Shot Killer", for his ability to pull off extremely precise shots. He was a soldier possessed of a mild personality, who conceded kill credits to his less experienced wingmen during combat. Unlike other Ace pilots who color their units with a personal color and emblem, Breniss liked using units with their standard colors. Breniss was against deploying inadequately trained pilots to the front lines and he never fires on enemies who are fleeing. Shortly before the end of the war, Breniss was removed from combat duty and was transferred to a pilot academy as an instructor. He is the instructor of the famous Chimera Corps, where famous ace pilots like Johnny Ridden and Thomas Kurtz etc. are all his students. He was the overall top scoring mobile suit pilot of the One Year War, and whose personal tally consisted of 193 MS shot down and 8 ships sunk. He was reported to have encountered Federation ace Tenneth A. Jung in battle.