Master chief petty officer
From Halopedia, the Halo wiki
Template:Ratings Template:Rank Infobox Master Chief Petty Officer is the ninth enlisted rank of the UNSC Navy, and is a non-commissioned officer. It is equal in rank to Master Gunnery Sergeant and Sergeant Major in the UNSC Marine Corps. Master Chief Petty Officer ranks just above Senior Chief Petty Officer.
Spartan-117 holds the rank Master Chief Petty Officer. Through out the Halo series, he is incorrectly called "Chief." This is unacceptable in the Navy. In the Marine Corps, a Gunnery Sergeant, as an example, may be called a Sergeant. The Navy uses different rules.
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