The Keepers of the One Freedom are a religious terrorist-militant warlord coalition comprising an extensive network of cells in both human and Covenant-held space. Led by Jiralhanae priest-chieftains known as dokabs, most of these cells are in practice relatively independent factions within the Keepers' banner with a number of doctrinal differences depending on the preferences of their dokab and the realities of their astrographic location. Having formed as a splinter of the Truth-loyalist Torchbearers in 2555, the Keepers had grown relatively widespread by the 2560s, assimilating various lesser Jiralhanae war-packs under their banner. By 2565, their cells had operations across the spinward reaches of the Covenant's former holdings, along with a number of human colonies. This includes the Tirn Flux Zone in the Siakar Expanse

As indicated by their name, the Keepers emphasize the One Freedom tradition of the Covenant religion, which continues to venerate the Great Journey as the centerpiece of their faith. The Keepers are notable, albeit not altogether unique, among post-Covenant groups thanks to their acceptance of humans into their ranks, and the only major Jiralhanae-led group to reject the "Truth Doctrine" of the 9th Age of Reclamation, which called for humanity's extinction. This has attracted an increasing number of humans into their ranks, largely radical adherents of preexisting Forerunner-centric neo-religions such as the Celestial Highway cult. This does not make them tolerant of the UNSC and Phoenix Initiative, which they consider an "infidel" regime along with virtually every other polity that does not subscribe to the Keepers' particular brand of Forerunner worship. Due to their continued presence in the border of the Outer Colonies, they are considered one of the more acute threats the UNSC following the defeat of the Torchbearers in human space.