|This serves as a notice that this article is incomplete and should be fixed, finished, or revised as soon as possible.|
- All Sangheili, all of Sanghelios, rise and we shall rebuild that which the San'Shyuum have sown in lies! Today, we reform the foundations of this great Covenant
- —Zuka 'Zulee
The Covenant Empire is a theocratic hegemony made up of multiple alien species that maintain control over a large portion of the Orion Arm in the Milky Way galaxy. The Covenant is a political, military, and religious affiliation; originally, it was a mutual alliance between the San'Shyuum and Sangheili following a brutal conflict between the two warring races. It expanded to include at least six other species that served their own purpose in the Covenant. The Covenant is united in their belief in the Forerunners as gods, and the promise that activating the Sacred Rings will kick start their transcendence known as the Great Journey.
They waged a genocidal war with humanity which lasted until their defeat and collapse in 2552. Because of internal strife, changing of the guards, and stubborn human resistance, the Covenant reached a boiling point and eventually collapsed.
In a chance encounter between the San'Shyuum Reformists and the Sangheili on Sanghelios, the two religious and indifferent species waged a long war with each other. The San'Shyuum had the Forerunner Dreadnought at their side, and it gave them naval superiority. The Sangheili were forced to adapt which meant integrating Forerunner technology into their warships and weapons. In the end, the San'Shyuum were victorious and a deal was struck, the Sangheili would convert their religion and become the protectors of the Prophets as they searched for transcendence.
The Writ of Union was signed. The San'Shyuum and Sangheili began their religious campaign to search for the technology left behind by the Forerunners, and to integrate that technology into their Covenant. During this search, the Covenant encountered several other species. The first encounters with these species were usually violent, but always ended in Covenant victory.
The Lekgolo, Yanme'e, Kig-Yar, Unggoy, and Jiralhanae were all enlisted into the Covenant and expected to adopt the belief in the Great Journey. Other species were encountered, but likely adopted as slave species put to work. The Huragok were another species widely adopted into the Covenant. Their engineering capabilities were uncanny, and they were creations of the Forerunners. Their adoption was necessary for making the Covenant into this great empire.
The Covenant encountered humanity on Harvest in 2525. The first meetings were violent, much is to be blamed on the fact that humans were living on a world with hundreds of Forerunner relics. At least, this was the initial belief, but an encounter with Mendicant Bias proved that readings were acurate, humanity was chosen to be the reclaimers of all the Forerunners left behind.
Devastated by this revelation, the San'Shyuum who knew the truth, that this information would break the Covenant religion, rose to power and declared humanity an affront to the gods. The High Prophet of Truth, Mercy, and Regret began their genocide on mankind. Harvest was the first to be glassed, a purification process necessary to "please their gods."
The Covenant began seeking out human-populated worlds and glassing them one after the other. The United Nations Space Command was unable to prevent the Covenant from glassing their worlds. The alien empire was too powerful, and just one of their ships were able to challenge an entire battle group. There were times throughout the war that the UNSC defeated a Covenant fleet and protected their world. Sigma Octanus IV, Aragon, and Earth are all worlds that were saved.
The Cole Protocol was initiated in 2535 to prevent the Covenant from discovering Earth and her colonies by destroying navigation datasets and performing random slipspace jumps. The delaying effort was successful, and it would take the Covenant 27 years to find Earth.
The Sangheili began to question the wisdom of the Prophets as to why humanity wasn't allowed into the Covenant. Through the war, they proved to be a determined and brave species. The Spartans were even regarded as demons because of their ability to kill hundreds of members of the Covenant.
Collapse and the Endgame
The greatest blow to mankind came during the Fall of Reach, the UNSC's military base world. It was heavily defended and guarded by several Orbital Defense Platforms. Even then, the world was glassed. The UNSC Pillar of Autumn made a desperate blind jump away from Reach, however, the Fleet of Particular Justice followed, and they discovered one of the seven Sacred Rings. Shortly after this discovery, the Flood emerged on the surface. It became a huge threat, and warranted the Covenant's attention. Little did they know, the Master Chief was working to destroy the Halo ring by detonating the ship's fusion reactors.
After the ring's destruction, political and religious strife began to tear at the Covenant. Heretics were challenging the Prophets, Jiralhanae were ascending to power, and the Unyielding Hierophant was destroyed. The discovery of Earth and Installation 05 was somewhat of a blessing, but it was short lived as the Prophet of Regret was killed by the Master Chief.
Several other events occurred which led to the schism between the Sangheili and San'Shyuum. Ultimately, the Prophet of Truth was planning to purge the Sangheili from the Covenant and become the supreme ruler. His ambitions led him to the Ark, Installation 00. When he was on the threshold of activating the Halo Array, he was stopped by the allied UNSC and Swords of Sanghelios. The Arbiter killed Truth, and the Master Chief stopped the array and nearly destroyed the Ark.
The Covenant is made up of a variety of alien species from different parts of the galaxy. Organized into a caste system by the San'Shyuum, the different species of the Covenant are united by their blind faith in the promise of the Great Journey.
The Sangheili were the warrior caste; the Unggoy were the worker class; the Huragok were the engineering class. Because of similar roles, there conflicts between species in the Covenant. The Unggoy and the Kig-Yar were both lowly castes, and contempt grew between the two species. The Sangheili and Jiralhanae were similarly warriors and their rivalry was well known. Even the Yanme'e had conflicts with the Huragok because of their roles as engineers.