Legion

A legion is a moderate size of Covenant ground troops, roughly equivalent in size to a UNSC battalion, which are made up of four maniples that are grouped together. They are commanded by either Jiralhanae Captain-Majors, or Sangheili Generals.

While maniples tend to be specialist organizations that combine vehicles and infantry in order to emphasize a desired role, legions are more generalist combined-arms units. They are the smallest Covenant ground formation to incorporate a true administrative council, which allows them to divide their forces and plan their attacks strategically. If a warhost proved itself, legions were permitted to adopt them under their command.

Warrior crèche
A warrior crèche is a training legion made up of young warriors who were not yet experienced enough to be seeded into other units. They could and would still be deployed to bolster Covenant ground forces, where they would typically undertake rear-guard defense duties or act as skirmishing troops, depending on the nature of the operation. Warrior crèches serve as the first major peer group outside one's keep and household for most male Sangheili. Such groups are tight-knit, and even as their members are distributed into other units, bonds between the members of a crèche are often retained throughout one's life.

Dragoon
A dragoon is a specialized legion of mechanized infantry, where lightly equipped troops were paired with troop transports and dropships to dramatically increase their mobility.

Penal legion
Penal legions are units made up of convicted criminals and other miscellaneous delinquents, including murderers, rebels, anarchists, pirates, heretics, apostates, outcasts, and deserters. Regarded as utterly expendable, with death being their only hope of redemption, they are poorly armed and armored, and are usually deployed as shock troops and cannon fodder on missions with the least chance of survival. Penal legions that had already distinguished themselves in battle could become a type of shock troops known as Storm. These would be frequently assigned on Executioner-order vessels and were rarely used in intra-Covenant conflicts. In rare cases, Executioner troops could win back their honor and status by serving with distinction.

Penal legions could also be formed out of select Covenant populations who had gravely transgressed against High Charity's rule and made an example of. For example, rebellious Unggoy colonies or Kig-Yar repeatedly engaged in grave crimes such as piracy against ministerial vessels or stealing holy relics might have their technological privileges revoked, with their populations forcibly reduced to a planet-bound state. While this was not common, mass levies from such "feral" or otherwise low-tech worlds were also used to form penal legions notorious for their savagery. Such units were usually assigned on the least honorable duties and effectively deployed as cannon fodder, meant to overwhelm the enemy with sheer numbers, kamikaze tactics or simply terrorize the enemy. To facilitate this, many Unggoy in particular were given combat drugs which drove them into a murderous frenzy. The deployment of such troops against mainline Covenant populations such as rebellious Sangheili worlds was virtually unheard of and, if it happened, would be a major scandal.

Unfortunately, however, such legions were also one of the Covenant's primary means of carrying out their campaign of extermination during the Human-Covenant War, partly because the Prophets faced increasing difficulty mustering mainline legions to fight such an increasingly unpopular war. On campaigns where they were present, they would be deployed into civilian population centers and were known for their cruelty. Even many Covenant commanders found this distasteful, and would often elect for glassing the planet directly over such terror tactics.

Auxiliary legion
Auxiliary legions are forces which are not integrated with the Covenant's hierarchy and rank structure and are not officially personnel of any ministry. These are typically being composed of fringe species, but may also consist of full member species from worlds that are not in regular contact with the Holy Ecumene at large, or simply have divergent martial traditions. Kig-Yar or Unggoy and even Sangheili levies could often be organized into auxiliary units, especially on short notice; this was most common in the Covenant's Late Antiquity and Feudal Periods. The Jiralhanae who settled in the Covenant's coreside-spinward marches were famed as longtime auxiliaries in the decades and centuries before their assimilation into the Covenant in the 23rd Age of Doubt. Though their commanders would report to a Covenant superior, such legions operated largely independent of the Covenant's command structure and were typically deployed separately of mainline Covenant forces, often in the Covenant's peripheries.

Known legions

 * 56th Dasim of Eayn Dragoons
 * 9th Dragoon Legion
 * Swords of the Third Sun
 * 17th Air Defense Legion

List of appearances

 * Not All Who Wander