Combat knife

The Combat Knife, occasionally referred to as the Close Quarters Combat Weapon System, is a multi-purpose knife used by the United Nations Space Command.

Design details
The UNSC's multi-purpose combat knife has a 20 cm blade made of high carbon steel, an anti-flash non-reflective titanium carbide coating, edge coated for corrosion resistance and is 43.3 cm when sheathed. All UNSC troops are issued a combat knife for field and utility uses, as well as a backup weapon for desperate close combat situations. It is also balanced for throwing.

History
Knives have been used in battle almost since the dawn of warfare, first as a sharp piece of rock, and then when metal proved effective during a period of time where projectile weapons were not readily available. Even after the invention of the firearm, knives were still used as bayonets for close-quarters-combat and in the event of an enemy's cavalry charge. As more modern times came about during the 21st century, combat knives became almost exclusively used for utility purposes in the field, and were only used as a weapon during desperate situations, simply due to the fact that they were impractical for use during combat in most situations due to firearms and other advanced weaponry.

By 2553, the UNSC still uses knives in their operations, showing that such an easily accessible and created weapon and tool still runs strong even thousands of years later.

Appearances
A larger version of the combat knife, called the machete, was intended to be used in pre-releases versions of Halo: Combat Evolved build, but was cut before it made it into the final game, replaced with the game's use of melee attacks from any weapon.

The combat knives make their first gameplay appearance as ornamental add-ons on the lower backs of Orbital Drop Shock Troopers in Halo 2. The combat knives also appeared in Halo 3 live-action commercial trailer Halo: Landfall, attached on the ODST's left shoulder. The weapon returns to Halo 3 as ornamental add-on for the MJOLNIR CQB permutation, as a sheathed combat knife attached to the left chest section.

The combat knife is first used in hand-to-hand combat in Halo Wars, when Sergeant John Forge uses his combat knife, which he has nicknamed "Lucy", to wound the Arbiter before killing the Sangheili leader with his own energy sword. Another scene where the combat knives is used was in Halo 3: ODST, where Gunnery Sergeant Edward Buck uses to kill a Jiralhanae Chieftain by stabbing him in the neck, afterwards casually flicking the alien's blood off its blade. In the Halo Legends episode The Package, Frederic-104 uses two combat knives to fend off and kill the two Sangheili from pursuing Kelly-087 and John-117 inside the Covenant flagship. These knives are stored in the pauldrons of Frederic's Mark IV MJOLNIR armor.

In the Halo: Reach world premiere cinematic, Emile-A239 is seen sharpening a kukri against his shoulder plate. In-game, the combat knives are used to perform extended melee kill sequences called assassinations by holding down the melee button when behind an opponent.

By default, all players have their knife holstered on the upper-left of their chest. However, a few chestplates can alter the position of the knife, such as the "Collar/Patrol", "HP/Parafoil", "Assault/Sapper" and "Collar/Breacher" Variants (among others). The Security right-hand shoulder variant has a Kukri attached to it similar to the one worn by Emile.

Trivia

 * Frederic-104 possesses particular skill with combat knives, and is rather fond of their use.
 * When performing an assassination, a second knife spawns out of nowhere. This can be seen in Theatre: despite using a knife to assassinate your opponent, it still appears sheathed on your chest.
 * In Halo:Reach, one of the Spartans's assassination animations is the same as how Buck killed the Brute Chieftain in Halo 3: ODST.

Internal

 * Curveblade
 * Energy Cutlass
 * Jiralhanae Combat Knife

External

 * Bayonet on Wikipedia
 * Combat knife on Wikipedia