Q was a leading member of Q traditionalists in the Q Continuum during the Q Civil War in 2373.
In an illusion of the American Civil War created by Q, so that Captain Janeway could comprehend the Continuum, this Q was represented as a colonel in the Confederate Army.
Near the end of the war, Colonel Q attacked and surrounded the manor that Q and Janeway were in, where he requested Q's surrender. Q refused and both he and Janeway were able to escape.
Janeway later entered Colonel Q's encampment and requested a cease fire on Q's behalf, stating that Q had a resolution for ending the war. Colonel Q admired her bravery for entering the camp unescorted and unarmed, but ultimately told her that Q was to be executed. He subsequently arrested Janeway for "collaborating with the enemy," which he also stated was a crime punishable by death.
The following day, as Colonel Q prepared the firing squad, members of the opposing forces, which included members of the USS Voyager crew wielding Q weapons, attacked his encampment, and the Colonel was eventually captured by Tom Paris.
Following his capture, he was instructed to call off his troops by the female Q, which successfully brought an end to open conflict of their Civil War. (VOY: "The Q and the Grey")