Sergeant Major
From Starbase 900 Wiki
In the Starfleet Marine Corps, Sergeant Major is the highest enlisted rank. Sergeant Major is both a rank and a military billet. Marine Corps sergeants major serve as the senior enlisted marine in the Corps' units of battalion, squadron or higher echelon, as the unit commander's senior enlisted advisor and to handle matters of discipline and morale among the enlisted marines. Sergeant Major is equivalent to Master Chief Petty Officer.
