Universal Conversion

"Let it be known that henceforth, the Sacred Revelation of the Great Journey shall be made known to all living creatures blessed with thought and reason, should they carry within them the light of Discernment. Let our Covenant welcome thinking beings, all without exception, and educate them in our ways, and let them be granted a role and place in our holy union, that they too may strive to one day join the Divine Ones when the Awaited Ascension comes. For all discerning creatures who live today were graciously sheltered from the Enemy by our Gods, who saw in all of us the potential to one day follow in Their footsteps."

- The High Prophet of Clemency in the concluding address to the Grand Convocation of Benefaction, 10th Age of Reconciliation.

The doctrine of Universal Conversion was a core guiding principle of the Covenant religion and policy in effect for much of the hegemony's existence. According to the doctrine, all beings capable of understanding the message of the Great Journey should be made to do so, and brought into the Covenant collective as per the divine mission given to the Prophets. This was because the Forerunners had blessed all sapient species with safe haven from the Enemy, that they may one day rise and uncover the secrets of the Journey to join the Gods in divine transcendence. Species (and, technically, individuals) incapable of understanding and embracing the concept of the Great Journey were considered unable to walk the path, and thus little more than beasts. While ostensibly a spiritual mission, the subjection of external cultures benefited the Covenant both in terms of providing new expertise or labor. Bringing species into the Covenant fold was also useful as it eliminated potential rival powers. This was not always possible, however, with several starfaring Ulterior civilizations existing outside the Covenant's sphere of influence.

This belief solidified following the integration of the Unggoy. At the time of the species' discovery, the Covenant had no established policy for automatically integrating new species into the hegemony's hierarchy. While the Lekgolo had been brought into the Covenant fold early on, this was due more to their utility than genuine evangelism; yet in their extreme enigmatic nature, set the standard for universal conversion. Still, even the Unggoy were initially a source of confusion as there was no consensus on whether they were capable of truly comprehending the gospel of the Covenant faith, though many of them would later become one of its most devout adherents. Though many within the Covenant wished to convert the Unggoy, there was no expectation that they would be fully assimilated into the hierarchy across the empire. Some Sangheili in particular objected, maintaining that a species should only be accepted if they proved themselves "worthy" in some way, though this belief would later be overridden by a Grand Convocation ruling which established that all species blessed by the Librarian should be worthy by default, unless they had committed unforgivable sins (and possible sins of that severity were not many, on a species-wide level).

Even so, Covenant conversion has never been a one-size-fits-all process. Each case has been different, varying by the traits of the species, as well as the needs and the circumstances the Covenant found itself in at the time. Total conversion was not only a religious but also a socio-political decision with an impact that would resonate across the Holy Ecumene for centuries. Despite the doctrine, there are many interpretations as to just what "conversion" entails, and how long it should take. The doctrine does not decree that total conversion must proceed immediately. A species achieving total client status and integration to the hierarchy may take time even if inroads are made into religious conversion because of how large of a societal step the process represents. The decision to fully integrate a species has a definite utilitarian aspect as well; the Covenant is most eager to take in species that can offer some practical use. All of the major client species provide some tangible benefits and fill a need within the hierarchy; if this is not the case, assimilation may stall indefinitely. For example, the Covenant was much more eager to welcome the Unggoy into the fold than the Rhiln due to the latter's physical weakness in comparison to the former. Because assimilation is not cheap or easy, there are always forces within the Covenant that want to keep the current status quo as long as possible. And when initiated, assimilation takes many Ages to fully take effect, and species generally take centuries to find their niche within the Covenant.

Species that occupy the hazy middle ground between outside cultures and full Covenant subjects are generally grouped together under the Covenant fringe category, though this is a wide gamut including species under conversion both in reality and those whose integration is proceeding in name only. Some species in the fringe are technically already client species, but their numbers are too small to make a difference. The Xar-Shaa, for example, were left largely to their own devices due to their extreme Enigmatic nature and lack of physical utility, while the conversion of the Cix-Tu was delayed indefinitely by internal unrest within the Covenant as well as the distance to the Cix-Tu homeworld. Others were too militarily powerful and had their core worlds too far from the Covenant sphere to be feasibly converted by force, whereas the Gryunjalla had largely left the Orion Arm by the time the Covenant came across them. The Jiralhanae remained in a fringe status for nearly a millennium before their formal assimilation into the Covenant hierarchy largely due to the overall chaos of the Feudal Period they were encountered in. Other fringe species, such as the Ior, Ikjuttar, and the Rhiln survivors experienced drawn-out or half-hearted conversion processes that were never brought to their conclusions before the fall of High Charity.

The Human-Covenant War troubled many believers in part due to the deeply-held belief in Universal Conversion as the Covenant's underlying mission. Even if the humans had committed sins, should they not be made to see the error of their ways and be brought into the Covenant? Such concerns fell on deaf ears, however, and the Hierarchs instead began silencing dissent, sowing the seeds of the Covenant's downfall. As it represents an all-encompassing cultural and social process, the doctrine of Universal Conversion is generally not understood to be solely about religion. After the war, some Sangheili have even invoked the doctrine and asserted that Humanity should be assimilated into the Covenant collective in the forms it now takes, with such voices being sometimes heard in the Concord of Reconciliation but more so the True Communion after the latter's establishment.