Keepers of the One Freedom

The Keepers of the One Freedom are a religious movement operating in the post-Covenant War era. They follow the religion of the former Covenant and its belief in the Great Journey, but also renounce the San'Shyuum as false "prophets." Their capital has been established on the human outlaw colony of Venezia, but they also have allies on Gao and other worlds, including Forerunner installations. The Keepers are led by a small group of Jiralhanae elders called Dokabs, most of whom are formerly high-ranked members of the Covenant military.

The detachment of Keepers led by dokab Castor was destroyed in October 2559 during an effort to fire the Halo Array from the Ark. Even before the Keepers left for the Ark through a Slipspace portal on Reach, Castor had been forced to abandon or sacrifice most of his forces due to a massive eradication campaign by ONI using intelligence gathered by the Ferrets. Following the failure of the mission, the only surviving members of this detachment were Castor himself and the Sangheili Blademaster Inslaan 'Gadogai—both having abandoned the Keepers. Having learned the truth about his faith and the purpose of Halo, Castor sought to exact vengeance upon his enemies. Despite this loss, other remnants of the Keepers remain active, with their largest presence still based on Venezia.

Background
The Keepers are a Covenant remnant faction founded not long after the end of the Human-Covenant War. They are notable amongst the myriad of Covenant splinter groups for being one of the few to allow humans amongst their ranks. Consequently, this willingness to work with humans has earned them allies on several anti-UEG colonies such as Venezia and Gao, and their rapid rise in power has earned them the attention of several ONI intelligence assets.

Gao conflict
In 2553, a UNSC task force was dispatched to Gao with the mission of retrieving a suspected Forerunner ancilla. During their inspection, the term "ancilla" was overheard by Veta Lopis, who promptly relayed this information to Gao's Minister of Protection Arlo Casille. Arlo then informed the cult leader (Dokab) Castor about the ancilla, much to the Jiralhanae's delight, beginning a Keeper invasion of Gao to recover the "oracle". The attack on UNSC forces begun when the One Light landed in a staged inspection, dispatching 500 troops into the jungle. The first attempt to recover the ancilla involved sending a small Brute task force into the caves, where they encountered and were subsequently defeated by Spartan Blue Team. At the same time, the larger task force opened fire on the UNSC garrison at Wendosa, using mortars and snipers to suppress the UNSC marines. When Blue Team eventually emerged from the cave system into the war-torn town, they pushed through the Keepers to Hotel Wendosa to link up with what remained of the garrison. Although Blue Team would be evacuated by a Falcon, the aircraft would be shot down by Keeper snipers, crash-landing in the jungle nearby. Castor and his pack would move in to engage the survivors of the crash, but would eventually be defeated by Blue Team. Castor was presumed dead after sustaining grievous injuries at the hands of Frederic-104, but would later encounter the Huragok Roams Alone, who would heal the injured Jiralhanae. Castor and Orsun then proceeded to leave Gao, with plans to exact vengeance on Casille for betraying the Keepers.

RETRIBUTION
In December 2553, the Keepers of the One Freedom became the primary suspects for the assassination of a UNSC admiral and the kidnapping of her family. Posing as pirates, Veta Lopis' Ferret team managed to infiltrate the Keepers Salvation Base on Taram where they discovered the bodies of the admiral's family, but realized that the Keepers were being framed by Dark Moon Enterprises. The Keepers came into conflict with both the Ferrets and Blue Team who destroyed Salvation Base with six HAVOK tactical nuclear weapons. It was estimated that the blast destroyed ninety percent of the Keeper forces on the base and would cripple their operations throughout the entire sector.

However, before the explosion, the Keepers were able to capture two of the Dark Moon operatives and from them, track the culprits to a laboratory on Gao. The Keepers destroyed the lab and captured its director who, worried about Dark Moon's plan for the Tuwa's organs, aided the Keepers in tracking Dark Moon to Pinnacle Station. There, Castor's forces came up against Papa-10, a rogue ONI unit working for Intrepid Eye. During the battle, Orsun was killed by Lieutenant Bartalan Craddog with an M41 SPNKR before Papa-10's survivors fled to the surface of Meridian. The Keepers chased Papa-10 to the surface where all of the attackers but Castor were killed by the rogue unit, Blue Team and the Ferrets. Papa-10 was ultimately killed by Veta and Castor and the cryo-jars holding the organs of the Tuwa family were destroyed. Castor was left stranded on Meridian with a broken translation disk looking for a way off while the Keepers were cleared as the culprits behind the assassination which turned out to be a bioweapon plot. Intrepid Eye was able to avoid discovery as the true culprit which was believed to be Craddog. However, the destruction of her remote aspect Oriel left her unable to confirm whether or not Castor was killed or if any of his cell survived.

Decimation
In around 2557, the Ferrets manage to infiltrate the Keepers of the One Freedom through an allied doomsday cult called the Humans of the Joyous Journey. Over the course of eight months, the Ferrets gather intelligence that they pass on to ONI, allowing the UNSC to conduct a massive eradication campaign against the Keepers. The intelligence results in the deaths of around 15,000 Keepers and the decimation of the faction.

Alliance with the Banished
At some point near April 2558, six months before the rise of the Created, the Keepers entered into a temporary alliance with Atriox's Banished, serving as one of its legions. Castor's decision to take refuge with the Banished greatly surprised ONI, who instructed the Ferrets to remain undercover in the hopes of a shot at killing Atriox. Shortly after this, Atriox and Decimus departed for the Ark, leaving Escharum in command. At some point in July 2559, they received a transmission from Escharum ordering them and two other Banished legions, the Legion of the Corpse-Moon and the Ravaged Tusks, to look for the hidden Ark slipspace portal in the Menachite portal complex beneath CASTLE Base on Reach. They succeeded in locating the portal by observing Blue Team's path towards Menachite Mountain. Soon after excavating it, Atriox activated the other end of the portal with the three shards of the Menachite Forerunner crystal and came through in a Lich. Castor, along with his forty surviving Keepers and the rogue Inslaan 'Gadogai, left the Banished and took the portal back to the Ark with the intent of activating the Halo Array.

The Great Journey
Upon arriving at the Ark, the Keepers' Lich crashed after getting caught in a three-way battle between the Banished, the UNSC, and a remnant of the Covenant that had survived the firing of Installation 08 from inside the Anodyne Spirit. Castor was able to form an alliance with these Covenant loyalists and their leader, Prelate Dhas Bhasvod, based on their mutual goal of beginning the Great Journey, aided by the unexpected appearance of Intrepid Eye. Chased by both the UNSC and the Banished, the alliance was able to locate and access Epsilon Clarion, one of the facilities on the Ark capable of firing the Halo Array. However, the journey and constant attacks decimated the Keeper detachment, leaving Castor and Inslaan 'Gadogai as the only survivors. In an argument between Intrepid Eye and a Facilitator-class ancilla, the Epsilon submonitor, overseeing the facility revealed the truth about Halo to Castor, who then abandoned his faith and mission. Epsilon Clarion and Intrepid Eye are destroyed by the and Castor and 'Gadogai, having abandoned the Keepers of the One Freedom, vowed to seek revenge upon all of their enemies.

Military assets
The Keepers have a wide range of former Covenant and human weaponry at their disposal, including mortars, Beam Rifles, Needlers, Plasma Rifles and more traditional Jiralhanae weapons such as the Spiker and Mauler. The Keepers also have at least one operational starship, the One Light and at one point, the Fleet of Glory which suffered heavy casualties during Operation: RETRIBUTION. Their manpower consists of hundreds, if not thousands, of soldiers of Jiralhanae, Kig-Yar and human species. Their allies on Gao and Venezia have ensured a steady stream of supplies and weapons to the faction, allowing them to conduct anti-UNSC operations in a large capacity. They are also known to use Jiralhanae power armor, painted blue and gold, for the colors of the Keepers.

However, by October 2559, the Keepers' ranks had been decimated due to a massive eradication campaign by ONI. Castor's forces that hijacked Atriox's Lich were all that was left of his detachment of Keepers, roughly forty in number. Despite this, numerous Keeper footholds remain across various planets and Forerunner installations, with the largest established presence still based on Venezia.

Personnel
Kalvo
 * Jiralhanae
 * Castor
 * Feodruz
 * Krelis
 * Orsun
 * Saturnus
 * Sangheili
 * Inslaan 'Gadogai
 * Kig-Yar
 * Human
 * Veta Lopis
 * Ash-G099
 * Olivia-G291
 * Mark-G313
 * Aubert Domhill
 * Quenbi
 * Knox

Starships

 * Great Light - Heavy frigate and Keeper flagship
 * One Light
 * True Light

Trivia

 * The Keepers are referenced in one of the weapon skins available for the plasma rifle in the Halo 3 component of Halo: The Master Chief Collection, released in Season 4: Reclaimer. Named Keeper, the skin's description reads Still searching for true freedom; an obvious nod to the name of the Keepers of the One Freedom. The plasma rifle skin itself is painted in a deep blue with yellow stripes.
 * They are also referenced in Halo Infinite by a colour option for Personal AI, released in Season 02: Lone Wolves, called Castor's Keeper and features a similar colouring.

List of appearances

 * Halo: Last Light
 * Halo Mythos
 * Halo: Retribution
 * Halo: Shadows of Reach
 * Halo: Divine Wind