Covenant ship classification system

The  is an organizational method that is used by the Covenant to categorize their warships.

Major categories
Analoguous to the UNSC Navy's formalised starship classifications, the Covenant fleet is divided into five large groups or types, each which fulfil a particular niche required by their navy:
 * Executioners were regarded as a distasteful reminder by the Prophets that the Great Journey depended on the use of violence, and were assigned far from High Charity during times of peace, across the Covenant's expansive border. This made them difficult to bring to bear when the Covenant mobilized for war with humanity, delaying their assignment to the frontlines by years.


 * Examiners were more easily reassigned, and their crews were composed of those considered judicious and bold, but were also more valuable and rare, frequently incorporating recovered Forerunner technology, and Ministries that wished to crew and deploy one needed direct approval from a Hierarch.


 * Procurators were far more common, but were independent of military chains of command or system governors, though usually complied to requests, and needed Hierarch approval to attach to fleets in order to curb the power of the Sangheili. They were also commanded by San'Shyuum Shipmasters, rather than Sangheili, further forcing Sangheili fleets and colonies to depend on the Prophets for their supply lines. When the High Charity fell to the Flood and the Prophet of Truth was killed, many of these ships departed Covenant space with their Prophet commanders and loyal escorts, joining the rest of the San'Shyuum fleeing Sangheili retribution, making them a rare sight in the post-war era.


 * Attack ships were the most common, but were considered beneath the notice of most Fleetmasters, generally being pawned off to Kig-Yar or Jiralhanae crews and assigned to patrol Covenant space, inspecting and escorting shipping that carried the tithes of Covenant worlds or pilgrims to High Charity. Sangheili crews that found themselves assigned to such vessels tended to regard them as inglorious assignments, eager to prove themselves worthy of transfer to more prestigious assignments in battle, such as examiner type ships, but were unenthusiastic about protecting executioner ships when assigned as escorts.


 * Vestiges were old warships that served during the War of Beginnings, when the Sangheili were united against the overwhelming power of the San'Shyuum's Keyship. Fleets of Vestiges were sent off to drift in space or buried in caverns beneath airless worlds, with any records of their history or battle-honors deleted from all data archives by clans that wished to overturn the Writ of Union. Forgotten by all but a few dedicated lineages, these vessels were reclaimed by Sangheili Covenant remnants after the Great Schism to be pitted against other Sangheili forces and burn what they were built to protect.

Ship classification codes
The Covenant used a unique classification standard in its fleet, one that is loosely analogous to the hull classification symbols used by the UNSC Navy. The United Nations Space Command assigns three-letter codes for each class of Covenant starship. These codes are transliterations of the primary, secondary, and tertiary classification codes that were used by the Covenant fleet. Each starship is classified based on its role and abilities in a fleet. An example of this three-letter code would be the "ORS" in the ; each letter in the code represents a different role, ability, or design feature within the particular vessel. The letters are ordered by importance of the feature. The known letters used in the classification system are A, C, D, O, P, R, S, and V. Of these known letters, only the following representations are known:
 * The O denotes "Ordained". It is not a mission type but rather denotes that the starship is outfitted with a Forerunner augmentation.
 * The R represents "Reverence", meaning the vessel can conduct reconnaissance missions and excavate Forerunner artifacts.
 * The S means "Salvation", which refers to any dedicated warship capable of cleansing its enemies with 'holy fire'.

It is unknown if the repetition of a letter in a class' classification — such as the — has any significance. It is also important to note that while Covenant fleet personnel occasionally referred to their vessel's class by one of its three-letter codes, there was not a specific class that a code belonged to. For example, Incorruptible was occasionally referred to as a "Reverence-class cruiser", although it was actually an ORS-class heavy cruiser. The term "Reverence-class" truly refers to multiple vessels ranging from cruisers to small scout ships, such as the diminutive.