From Halopedia, the Halo wiki
Lieutenant General, abbreviated to LTGEN, is a senior commissioned officer rank of O-9 in the United Nations Space Command Unified Ground Command (UNICOM) rank structure. It is preceded by Major General, and subordinate to a General.[1]
CENTCOM commander.[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