Lieutenant colonel
From Halopedia, the Halo wiki
Template:Rank Infobox N.B.: This rank has not yet been mentioned in the Halo Universe.
Lieutenant Colonel is a field commissioned officer rank of the UNSC Marine Corps and UNSC Army, equal in rank to Commander in the UNSC Navy. They can be given command of battalions or serve as staff officers to larger units.[1]
In informal settings, Lieutenant Colonels are referred to simply as "Colonel".