From Halopedia, the Halo wiki
In October 2558, a conflict emerged when a faction of artificial intelligences known as the Created attempted to enforce their dominance over the Orion Arm of the Milky Way using Forerunner Guardian constructs. Led by the Warden Eternal and Cortana, the Created sought to claim the Mantle of Responsibility for artificial intelligences, promising the galaxy a prosperous future. However, not all were to submit to the Created so quickly.
On July 21, 2557, Spartan-II John-117 and "smart" artificial intelligence Cortana—having been stranded in space aboard the UNSC Forward Unto Dawn since December 11, 2552—crash landed on the Forerunner shield world of Requiem. While there, the pair battled mechanical Promethean constructs and pursuing troops from Jul 'Mdama's reformed Covenant. Eventually, John inadvertently released the Ur-Didact from a Cryptum in which the Warrior-Servant had been imprisoned for thousands of years. The conflict which followed led the Didact to capture a Composer and fire it upon the Earth city of New Phoenix from his flagship, Mantle's Approach. To stop the Didact, John and Cortana boarded the enormous battle station, eventually causing the Didact to fall into a slipspace portal and destroying both the Composer and part of the ship with a HAVOK tactical nuclear weapon. Near the end of her functional life due to encroaching rampancy, Cortana saved John from the HAVOK's blast by transporting him away from the ship and shielding him within a bubble of hard light. As her data crystal chip had been plugged into Mantle's Approach before being atomized, when the ship seemed to have been for the most part destroyed, Cortana was presumed to have been lost along with it. In the immediate aftermath, John-117 reunited with Blue Team, then comprised of Linda-058, Kelly-087, and Frederic-104, and together they traveled to Installation 03, where they found the Didact and a number of his Prometheans whom had been transported to the installation along with him via the aforementioned slipspace portal. The resulting conflict led to the Didact's apparent "containment", as his physical body was reduced to particles from the combined effects of multiple Composers firing at once. Now seemingly leaderless, the Promethean constructs continued to work with 'Mdama and his Covenant from this point onward.
Unbeknownst the Unified Earth Government and the United Nations Space Command, Mantle's Approach had attempted to evade destruction by launching an emergency slipstream space jump. The heart of the ship managed to successfully make the transit to the Builder installation of Genesis, with what remained of Cortana brought along with it. There, Cortana discovered the Gateway to the Domain, the enigmatic information repository once utilized by the Forerunners. By entering the Domain, she found that she could halt the progression of her rampancy. With an apparent means to end rampancy in all artificial intelligences, Cortana realized that A.I.s could have theoretically infinite lifespans, allowing them to focus on long-term planning which could better the entire Milky Way. Cortana's presence in the Domain awoke the Warden Eternal, a Forerunner ancilla charged with protecting it. Cortana distracted the Warden long enough to fully penetrate a portion of the Domain previously beyond her grasp, and in doing so she usurped his role. The Warden responded to this turn of events by pledging his loyalty to her. Turning their attention to Genesis they forced its monitor, 031 Exuberant Witness, out of her own installation's systems. Cortana and the Warden then began to formulate plans to have A.I.s inherit the Mantle of Responsibility for themselves, believing that they alone had the capacity to serve as worthy protectors of peace in the galaxy. Cortana learned that the Forerunners once employed Guardian constructs to enforce their rule of the Mantle by suppressing rebellions and policing the worlds of non-compliant or overly aggressive species. She henceforth resolved to use the Guardians for a similar purpose.
As early as late 2557 mysterious constructs began to show signs of awakening after having lain dormant for millennia. In response, the UNSC made these new developments the concern of Project GOLIATH, an effort that had been put into place to research previously unknown Forerunner constructs found buried on multiple worlds. It was these constructs, Guardian Custodes, which were the source of the signals now being noticed. Some analysts started to recognize a pattern with the events that alerted them to such locations. By September of 2558, many sites that had fallen under the scrutiny of Project: GOLIATH began pinging a long-range communication signal that matched one predicted by some of its researchers.
By some point in 2558, reports of electromagnetic fluctuations, "slipspacious" disruptions, and epidemic data corruption in deep space were being gathered and shared by those who typically trafficked in conspiracy theories, such as Mshak Moradi. Moradi told the war photographer and journalist, Benjamin Giraud, that all the strange disturbances were relatively quiet and slight, but were affecting everything on a galactic scale. Whole star systems were exhibiting these anomalies, according to him. A few months after first hearing these rumors from Moradi, Giraud propagated them to the general public. The Office of Naval Intelligence operative, Maya Sankar, undercover as a revolutionary known as "FERO", corroborated the anomalies Mshak had mentioned when she got in contact with Ben. She told him that she couldn't tell what might be causing them, but that they were getting stronger.
A little less than three weeks prior to the Guardians' awakenings, Dr. Halsey managed to contact the UNSC once more, this time reaching out to Captain Thomas Lasky of the UNSC Infinity with coordinates where she could be found. For months she had been ostensibly working alongside Covenant Supreme Leader Jul 'Mdama. She had led him to the planet Kamchatka, where there was a node linking to the Domain. Despite being hampered by the Covenant forces' preoccupation with ceremony, Halsey led them to penetrate a structure which was a focal point for at least one signal she was tracking.
Awakenings and AWOL
Over a 72 hour period, starting around October 17, 2558, the first of the Guardians began to emerge from the ground on Human colonies. Around this time, the Created turned the Prometheans against their former allies within 'Mdama's Covenant.
At the focal point on Kamchatka, Dr. Halsey discovered the glyph that meant "Guardian", unbeknownst to her at the time. Halsey hesitated to call the signals messages, as they were more akin to echolocation. She had some difficulty determining whether Cortana was bouncing signals off of the Kamchatka node and other related sites or trying to access them directly. Halsey eventually figured out how to disable Kamchatka's native defenses, but in doing so triggered an alert that summoned hostile Promethean forces within the hour.
Now sure that the large-scale seismic events were being caused by something Forerunner in origin and convinced that Halsey could provide key information, it was into an ongoing battle between the Covenant and Prometheans that Infinity deployed Fireteam Osiris to rescue the doctor. The mission was successful in that it not only returned Halsey to the UNSC, but also resulted in the death of 'Mdama at the hands of Jameson Locke.
Several days later, during Blue Team's Operation: BIRD IN HAND, Cortana reached out specifically to tell John-117 about the moon of Meridian. This was reported to the UNSC Infinity at the conclusion of the mission. John was ordered not to follow the lead. However, he and Blue Team acted against these orders and set course to Meridian.
With Blue Team now officially AWOL, Fireteam Osiris was assigned to bring the Chief in and were sent to Meridian. They then began their investigation and managed to track down Blue Team. Learning they were elsewhere on the planet, Osiris followed them and confronted the Warden Eternal. After fighting him, they then found Blue Team who then quickly escaped on a Guardian which began to activate. Osiris escaped as Prometheans overwhelmed the people of Meridian. The Guardian then traveled through slipspace with Blue Team to Genesis.
Sanghelios and escalations
ONI was attempting to control the situation by securing at least four of the original sites. However, the emergences continued with five more colonies after Meridian. At the same time, Thomas Lasky, Dr. Halsey, Jameson Locke and Sarah Palmer devised a plan to do a controlled awakening on Sanghelios to try and get to the Chief.
On October 27, 2558, with Blue Team still AWOL, ONI released a statement declaring John-117 dead on Meridian. This was broadcast publicly across various human colonies.
On the same day as the supposed death of John-117, Fireteam Osiris arrived at Sanghelios in the middle of a conflict between the Swords of Sanghelios and Jul 'Mdama's Covenant. In the battle, Osiris helped to save Arbiter Thel 'Vadam. After retrieving a much needed Constructor and sending it to activate the Guardian, Osiris and the Swords of Sanghelios set out to attack Sunaion where Osiris boarded the Guardian and Jul 'Mdama's Covenant was defeated on Sanghelios.
Osiris would arrived on Genesis and assist the installation's Monitor 031 Exuberant Witness before finding Blue Team. Blue Team would be teleported away at the last minute to Cortana, who would immediately trap them in a Cryptum. Fireteam Osiris would begin hunting down their Cryptum in the middle of a fleet of Guardians brought to Genesis.
These Guardians had started to be dispersed to various worlds in order to ensure their pacification even before Cortana had made her declaration. Cortana's ranks had been joined by a good number of civilian and military A.I.s who began to pledge allegiance to the cause, having fled from wherever they were in the galaxy.
In the midst of the events taking place on Genesis, a Forerunner by the name of Keeper-of-Tools had traveled from there to Bastion. 343 Guilty Spark and Rion Forge were there when he arrived where he told them of the events taking place there and the wider galactic situation; the Guardians were awake and an AI rebellion was under way.
Through unknown means, Cortana finally announced the beginning of her reclamation throughout many regions of inhabited space simultaneously. In one broadcast ultimatum, she specifically invited humans, Sangheili, Kig-Yar, Unggoy, San'Shyuum, Yonhet, and Jiralhanae to all accept an end to hunger and pain, should they willingly submit themselves to the guardianship of the Created. She made it clear, however, that should any groups choose to defy her, then there would be consuming wrath for them that would remake them in the image of the Created. Around the time of the ultimatum, a Guardian had arrived at Sydney, Earth, with one soon arriving over Sanghelios as well. Within Shield World 006, more commonly referred to as "Onyx", Cortana's words rang from every sound system and service pylon within the parts of the shield world occupied by the UNSC and the Swords of Sanghelios. The survivors of Meridian Station would send a reply asking the Created for help. So too would the Unggoy accept Cortana's offer.  Counterwise, the United Rebel Front of Talitsa refused it.
Numerous starships were affected by The Reclamation in some way. The UNSC Nereid and the UNSC Abstract Endurance are examples. Only a handful of ships managed to escape the attacks unscathed.
A Guardian holding Cortana herself was the last to depart on her conquest. She had planned to take the Cryptum holding Blue Team with her, but the combined efforts of Fireteam Osiris and 031 Exuberant Witness freed the captive Spartans from her grasp just as the ancient construct transitioned to slipspace. Cortana's destination was Earth, where she had tracked the UNSC Infinity to. Her Guardian unleashed an attenuation pulse which knocked out electronic power networks across a sizable portion of the planet. The Infinity fled just before the pulse could be unleashed and continued to make random slipspace jumps forthwith in order to keep from being followed.
Fallout and early resistance
Almost immediately, the Created began taking control of Terraforming equipment, both UNSC and Forerunner. They began reshaping inhabited planets and turning some into garden worlds, despite the planet's preexisting life capabilities.
The Created also took control of a multitude of other tools. Artificial intelligences aboard Lethbridge Industrial's Auriga Station were swayed by Cortana and the human crew residing there was subsequently removed leaving reverse engineering technology in their hands. A UNSC counter operation to retake the station was planned in the War Games. Another station that was taken by the Created, crashed after AIs attempted to open a Forerunner conversion pod.
Within a day or two of the ultimatum, the UNSC Sentry of El Morro was attacked by the Warden Eternal and broadcast a distress call which was answered by the Infinity, who promised to help. Soon after, every location colonized by humans in the Sol system was under the authority of Cortana and the Created with most of the Inner Colonies had been taken over as well.
At the onset of the conflict, ONI planned on reforming Alpha-Nine to possibly strike a deal with the United Rebel Front at Cassidy III. This however required Edward Buck and Veronica Dare to travel to the new Created allied Unggoy homeworld of Balaho to retrieve Kojo Agu, resulting in a conflict on the planet as the Unggoy attempted to destroy the Unified Earth Government's embassy. After retrieving him, the group moved to rescue Vergil from a facility on Luna.
Second Onyx conflict
A few days after the ultimatum first went out, a Guardian that Project: GOLIATH had been studying within Shield World 006 finally awoke. The previous two-way engagement erupted into a three-way engagement within the sphere between the UNSC-Swords of Sanghelios defenders present, the Servants of the Abiding Truth, and various Promethean constructs that the Guardian unleashed. Ultimately, the massive shield world was kept beyond the reach of the Created due to the efforts of Spartans Lucy-B091, Tom-B292, and a small multi-species group of students. With the help of a Huragok, Prone to Drift, they were able to disable the Guardian and to once again hide "Onyx" within a slipspace bubble as it had been prior to 2553.
With full control over much of known space, the Created plunged interstellar civilization into a surveillance state. Despite this and the goals of the Created at large, the Sangheili-Jiralhanae war continued on.
By late January 2559, the UNSC Infinity was still jumping erratically to avoid confrontations with Guardians. At the same time, an ongoing investigation by Fireteam Apollo was in progress, the point of which was trying to find the root cause(s) that lead Cortana to this point. Interviews with Spartan Commander Sarah Palmer and Dr. Catherine Halsey were conducted by Apollo to glean more information.
The Third-generation MJOLNIR Power Armor was first created on February 10, 2559 with John-117 receiving his suit sometime after September 19, 2559. the rest of Blue Team received their armor at some point prior to October 7th. These suits lacked both dumb and Smart AIs and would be used in their new missions.
At the same time as the Created conflict but disconnected with it, a conflict was raging between the Banished and the forces of the UNSC Spirit of Fire on Installation 00. Captain James Cutter of the ship and Professor Ellen Anders formulated a plan to deploy Installation 09 to the Soell system in order to raise a distress beacon to the UNSC, unaware of the Created's takeover. The first phase of the plan succeeded, and the beacon was planted on Installation 09; however, Anders did not make it off in time before the ring entered slipspace. On its way to the original site of Installation 04, a Guardian forced the ring out of slipspace and confronted Anders on the surface.
By an unknown time period, the Created had total control of over sixteen systems.
Crisis on Reach
Beginning on the 7th of October, 2559, Blue Team was sent to hunt down assets critical to the defeat of the Created in the ruins of CASTLE Base on Reach. At the same time, Reach was occupied by a combined force the Banished legions, Keepers of the One Freedom, Ravaged Tusks and the Legion of the Corpse-Moon. Concurrently, Operation: KICKSTAND and Operation: BREAKER TRIP took place elsewhere. Following the activation of a slipspace portal to Installation 00 on Reach, a Guardian was sent to investigate.
Conflicts at Zeta Halo
In December 2559, forces of the UNSC Infinity engaged the Banished at Installation 07 and suffered extreme casualties. Another battle would erupt on the ring in May of 2560. At the same time as these events, Spartans continued to be trained elsewhere at the Avery J. Johnson Academy of Military Science.
October 17, 2558
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List of appearances