From Halopedia, the Halo wiki
Master Sergeant, abbreviated to MSGT, is a Enlistment rank of E-8 in the United Nations Space Command Unified Ground Command (UNICOM) rank structure. It is preceded by Gunnery Sergeant, it is equal in grade to the command career track First Sergeant, and a subordinate to a Master Gunnery Sergeant and a Sergeant Major.[1]
Division administration.[1]
Master Sergeant is in the technical career track and directly leads onto the E-9 rank Master Gunnery Sergeant.[1]
Enlisted: Crewman Recruit • Crewman Apprentice • Crewman • Petty Officer Third Class • Petty Officer Second Class • Petty Officer First Class • Chief Petty Officer • Senior Chief Petty Officer • Master Chief Petty Officer
Enlisted: Private • Private First Class • Lance Corporal • Corporal • Sergeant • Staff Sergeant • Gunnery Sergeant • Master Sergeant • First Sergeant • Master Gunnery Sergeant • Sergeant Major