Rear admiral (lower half)
From Halopedia, the Halo wiki
Rear Admiral (Lower) is a UNSC Navy commissioned officer that is in Command of all ships at the back of a fleet mostly the least affective in combat. All though they sound alike Rear Admiral (Upper) is higher in rank and pay. This rank is above Captain and below Rear Admiral (Upper) and is equal to Brigadier General in the UNSC Marine Corps.
