Senior Chief Petty Officer

Senior Chief Petty Officer is an E-9 rank of the UNSC Navy it's non-commissioned officer.  It is equal in rank to Master Sergeant and First Sergeant in the UNSC Marine Corps and UNSC Army respectively, and Senior Master Sergeant in the UNSC Air Force. It is directly above Chief Petty Officer and directly below Master Chief Petty Officer.

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

Air Force

 * Airman Basic
 * Airman
 * Airman First Class
 * Senior Airman
 * Staff Sergeant
 * Technical Sergeant
 * Master Sergeant
 * Senior Master Sergeant
 * Chief Master Sergeant
 * Command Chief Master Sergeant
 * Chief Master Sergeant of Air Force

Army

 * Private
 * Private First Class
 * Specialist
 * Corporal
 * Sergeant
 * Staff Sergeant
 * Sergeant First Class
 * Master Sergeant
 * First Sergeant
 * Sergeant-Major
 * Command Sergeant-Major
 * Sergeant Major of the Army

Navy

 * 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
 * Command Master Chief Petty Officer
 * Force Master Chief Petty Officer
 * Fleet Master Chief Petty Officer
 * Master Chief Petty Officer of the Navy