This character is in charge of all Marine and wartime operations. He/she is responsible for maintaining a safe environment for the station crew and maintains and manages a military-only brig (deck 100) separate from that of Starbase Security. The CO-MC and his/her subordinates are authorized to use deadly force in any attempt to protect the Starbase from hostile forces within and from without.

The CO-MC has an office on Deck 99, the top of four decks dedicated exclusively to Marine forces and situated between SF and Civilian sections of the base. Deck 100 holds a brig capable of holding 40 men individually, more if paired/grouped up. The Ready/Alert forces stand ready on this deck as well. Deck 101 is the fighter craft flightdeck and holds the main (Marine) armory. Deck 102 is the barracks and supply level. The CO-MC controls the Marine flightdeck but with coordination via the station Flightdeck Officer.

This individual works closely with the Chief of Security for use of his forces and coordination of base security. The CO-MC is primarily concerned with (Starfleet) military matters and that of base security as a whole, leaving the Chief of Security to administer daily policing of the station itself, especially the civilian population unless assistance is requested. Martial law can only be imposed by command authority.

This position holds a general authority equal to that of the Chief of Security and reports directly to the starbase BC/CO plus SF Command-Marine CinC. During normal day-to-day operations the CO-MC defers to the Chf of Sec on all matters non-military. During times of war though his authority is only topped by the Starbase Commander himself.

This is a department leadership position and is heavily featured in almost all combat missions with many opportunities for activity.