From Halopedia, the Halo wiki
Skirmisher Commandos are a part of the T'vaoan Skirmisher contingent that are deployed by the Covenant. Commandos are specifically trained and designed to form specialized combat files and infantry hunter-killer units. Commandos operate in discrete close-knit groups with extremely specific mission parameters. Other members of the Covenant military recognize Commandos on the battlefield for their incredibly proficient unit cohesion.
The first Commandos were selectively picked from sectarian societies from the asteroids that orbit Chu'ot. The Kig-Yar on these asteroids were sustained by gray market trade and developed free from the government that dominated the Kig-Yar homeworld of Eayn. They were employed by the original Kig-Yar government's militia to fight off recurring looting and piracy that was common on the asteroids and other Kig-Yar colonies in an extremely ruthless and precise fashion. When the Covenant first arrived in the Y'Deio system, the Commandos joined forces with the pirates in an attempt to fend off the intruders.
Commandos generally wield the same weaponry and have the same armor ratings as lower-ranking Murmillones. Commandos wear olive-green armor and a helmet. Commandos are not equipped with energy shields. Occasionally in combat, they will utilize holograms of themselves in order to fool their enemies in attacking it instead of them. Commandos are typically armed with plasma pistols, needlers, needle rifles, and focus rifles.
List of appearances