From Halopedia, the Halo wiki
Lance Corporal, abbreviated to LCPL, is a Enlistment rank of E-3 in the United Nations Space Command Unified Ground Command (UNICOM) rank structure. It is preceded by Private First Class and subordinate to a Corporal.[1]
Fireteam assistant.[1]
The patch is red with two gold chevrons pointing up.[2]
Rank Patch from the UNSC Archives - Unspoken
Chris Preston from the UNSC Archives - Unspoken
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