Master chief petty officer

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.

In informal settings, Master Chief Petty Officers are typically called "Master Chief" or "Chief."

Trivia

 * Master Chief Petty Officer is a real-world rank in the U.S. Navy or in the U.S. Coast Guard, and is the next rank after Senior Petty Officer.
 * Those who have the rank of Master Chief Petty Officer are also usually called "Master Chief".
 * This is John-117's rank.