Commanding officer

The Commanding Officer is a billet position filled by officers that are in command of a particular duty, such as commanding a UNSC or leading a Marine unit. The status of commanding officer is duly applied to all commissioned officers who hold lawful command over a military unit, ship, or installation. Before a Naval officer is given control of a starship, they usually are given the rank of Captain.
In the Navy, commanding officer is the official title of the commander of a ship, but they are usually referred to as "the Captain" regardless of their actual rank, or informally referred to as "Skipper."Halo:Combat Evolved Captain Keyes (O.S.): "Bridge to Cryo 2, this is Captain Keyes. Send John-117 to the bridge immediately." / Tech Chief Thom Shephard: "Captain, we'll have to skip the weapons diagnostics and I-" / Captain Keyes (O.S.): "On the double, crewman." / Tech Chief Thom: "Aye aye sir. {Pause} The Skipper seems jumpy, we'd better get moving. We'll find your weapons later." However, there have been Navy COs that held the rank of Commander, such as Captain Keyes before his promotion to Captain during the Battle of Sigma Octanus IV.Halo: The Fall of Reach, page 161 Marine Commanding Officers are issued orders by a higher ranking Naval Commanding Officer if on board a starship.Halo: Combat Evolved Marine Battalion COs (known as Battalion Commanders) are usually Lieutenant Colonels, though Majors can fill this position if a Lieutenant Colonel is unavailable. Marine Platoon Commanders are usually First Lieutenants, and Company Commanders are usually Captains.
Commanding officers may be of any commissioned rank. Usually there are more officers than command positions available, and time spent in command is generally a key aspect of promotion, so the role of commanding officer is highly valued, and in theory only goes to the best officers. In a unit, the commanding officer is often assisted by an Executive Officer (XO) or Second-in-Command (2i/c), who handles personnel and day-to-day matters. Larger units may also have staff officers of various responsibilities. Commanding officers are one of many billet positions that are allowed into Officer's Quarters.
In the UNSC Army, the commanding officer of a platoon is referred to as a Platoon Leader. The commanding officer of a company is referred to as a Company Commander, the commanding officer of a battalion is referred to as a Battalion Commander, and the commanding officer of a brigade is referred to as a Brigade Commander. At the division level and higher, however, the commanding officer is referred to as the Commanding General, as these officers are normally general-grade officers. 
==Known Naval Commanding Officers==
NOTE: The list is incomplete.
Fleet Admiral
*Terrence HoodHalo 2Halo 3 (Fleet Admiral, CO of the UNSC Home Fleet)
*Harper
Admiral
*Carl Patterson
*Dale KilkinHalo: Evolutions - Essential Tales of the Halo Universe, The Impossible Life and the Possible Death of Preston J. Cole
*Harold Stanforth
*Konrad Volkov
*Preston Cole
*Roland FreemontHalo: The Fall of Reach
*Ysionris Jeromi
Vice Admiral
*Alexander ReavesHalo: Blood Line, Issue 1
*Danforth WhitcombHalo: First Strike
*Gerov
*Jean MawikiziHalo: The Cole Protocol
*Kopano N'Singile
*Margaret Parangosky
*Michael Stanforth
Rear Admiral
*Ned Rich
Captain
*Aaron G. Gibson
*De Blanc
*D. F. Lambert
*Edgar Sykes
*GreeneI love bees
*Iglesias
*Jacob Keyes
*James CutterHalo Wars
*Maribeau Veredi
*Serin OsmanHalo: Glasslands
*Veronica DareHalo 3: ODST
*Wallace
Commander
*Arthur Resnick
*Carter-A259Halo: Reach
*Dmitri Zheng
*HadleyHalo: The Cole Protocol, page 354
*Jerome G. Ortega
*Richard Lash
*Tobias FoucaultHalo: Evolutions - Essential Tales of the Halo Universe, The Mona Lisa
Lieutenant Commander
*Catherine-B320
*Fhajad-084
*Julian Waters
*Jilan al-CygniHalo: Contact Harvest
*Kurt-051Halo: Ghosts of Onyx
*Miranda Keyes
*Xaing Cho
Lieutenant
*Aki Hikowa
*Badia Campbell
*Bethany Durruno
*Dante Kirtley
*Elias Haverson
*Joe Yang
*W.K. Davidson
Lieutenant Junior Grade
*Bill Streeter
*David Brightling
*Fredric-104
==Known Marine/Army Commanding Officers==
NOTE: This list is incomplete.
*Kits (Marine/General)
*Nicolas Strauss (Marine/Major General)Halo: First Strike, page 103
*James Ackerson (Army/Colonel)
*Unnamed UNSC Colonel (Marine/Colonel)Halo 3: ODST, Uplift Reserve
*Antonio Silva (Marine/Major)Halo: The Flood
*Melissa McKay (Marine/First Lieutenant)
*Avery Johnson (Marine/Sergeant Major)
*Edward Buck (Marine/Gunnery Sergeant)
*Urban Holland (Army/Colonel)
*Jake Chapman (Marine/First Lieutenant)
*Duvall (Army/Sergeant Major)Halo: Reach, Exodus
*John Forge (Marine/Sergeant)
*Ponder (Army/Captain)
*Aboim (Marine/Lieutenant Colonel)
*Nolan Byrne (Marine/Staff Sergeant)
*Akio Watanabe (Marine/Major)
*Marcus Stacker (Marine/Gunnery Sergeant)
==Sources==
Category:Humans (Characters)
Category:UNSC Military Units