Post-Covenant War conflicts

Following the end of the Human-Covenant War in 2552, a number of new conflicts arose.

The Unified Earth Government and its United Nations Space Command remained locked in irregular hostilities between several remnant factions of the former Covenant, later seeing the involvement of Forerunner elements, specifically Promethean forces led by the renegade Ur-Didact, imprisoned millennia earlier by the Librarian, once humanity's greatest Forerunner supporter. This Forerunner aspect would come to define and greatly broaden the scope of the events, bridging directly into humanity's own prehistory and their ancient feud with the Forerunners. Meanwhile, the Sangheili were at war with each other, and resumed their feud with the Jiralhanae, who were also in a civil war of their own, meaning both species were fighting on two fronts. Various human rebel groups, most of which had been dormant during the Human-Covenant War, re-emerged in the post-war era, and at least one Covenant splinter faction joined them in their war against the UNSC.

In 2557, a reformed Covenant under the leadership of Jul 'Mdama gained access to the shield world of Requiem, home to the Didact, a legendary Forerunner Promethean whose aid the Covenant sought to enlist in their campaign against humanity. The ensuing series of skirmishes led to the Didact's release and an alliance between the Promethean forces and the Covenant, who revered the Didact as a "living god". Covenant forces subsequently helped the Didact retrieve the Composer, an ancient Forerunner device with the power to enslave mankind. Although the Didact was later defeated by Spartan John-117, the Covenant continued to occupy Requiem and to search for the Librarian. They contested the UNSC for control of the shield world again in early 2558; the drawn-out battle eventually culminated in the installation's destruction but not the defeat of the Covenant, who had already withdrawn most of their forces from Requiem. After ONI attempted to assassinate her on Requiem, Dr. Catherine Halsey began to collaborate with Jul 'Mdama in order to recombine the cartographical artifact known as the Janus Key and unlock the Absolute Record.

In late 2558, the Prometheans from Requiem would ultimately turn against Jul 'Mdama's Covenant, falling under the banner of the Created, who were led by Cortana and the Warden Eternal.

Background
"Decades from now, when historians evaluate the war, what will they say about us? Will they claim that our victory was ultimately fruitless? That it failed to secure a lasting peace, or worse, that it was only a prelude to far greater horrors that now lay ahead?"

- Codename: SURGEON prefacing the first Eleventh Hour report

Although the death of the Prophet of Truth at the Ark during the endgame of the Covenant War saw the ultimate defeat of the Covenant and humanity's truce with most Sangheili, represented by the Swords of Sanghelios, it was not long after the end of the war that rogue splinter groups began to rise from among the remnants of the hegemony. With large amounts of former Covenant matériel at their disposal, many of these disparate remnants opposed both the UNSC and the former members of the Covenant who favored a policy of peaceful cooperation, an approach most visibly embodied by Arbiter Thel 'Vadam. The UNSC's aggressive rearmament (largely made possible by the acquisition of Forerunner technologies and exemplified by the colossal warship as well as the rapid creation of hundreds of new Spartan supersoldiers) combined with the Office of Naval Intelligence's shortsighted approach to neutralize their former enemies, did little to ease the concerns of more hostile elements within Sangheili society.

While Sanghelios remained locked in a state of civil war between various factions, in part due to the clandestine activities of the Office of Naval Intelligence, a former Sangheili Shipmaster known as Jul 'Mdama created his own revival of the Covenant. During his time in ONI captivity on ONIRF Trevelyan, 'Mdama had learned that the Didact, a mighty Forerunner general with a hatred for humans, was trapped inside a Forerunner world known as Requiem. After escaping Trevelyan, 'Mdama began to gather followers in order to travel to Requiem and unlock the world's secrets, intending to use the Didact as a motivating force for his followers, but also a new spiritual voice for his people and a chance to exact vengeance on humanity.

Humanity found itself facing renewed internecine struggle as well. While the Insurrection had ceased as a major conflict at the start of the Covenant War in 2525, some surviving colonies still harbored former Insurrectionists as well as individuals sympathetic to the cause of colonial secession. Some colonies, including Venezia, cut off all ties with the UEG under the pretense that Earth had abandoned them during the war. Some rebel groups managed to obtain large amounts of Covenant and UNSC weapons and equipment circulating on the black market.

Insurrectionist attack on Infinity


In January 2553, elements of the New Colonial Alliance led by UNSC defector Ilsa Zane (the only survivor of the SPARTAN-IV program's prototypical stage) infiltrated the disguised as construction personnel and captured most of the bridge crew, using them as hostages. They then secured the ship's bridge in the hope of capturing the prototype UNSC flagship, threatening to vent the ship's atmosphere and kill everyone aboard it. The attempt was foiled by the first team of SPARTAN-IVs (who had recently been brought aboard) and the insurgents were all killed or captured. The prisoners revealed Admiral Mattius Drake as the organization's leader.

Continuing Jiralhanae-Sangheili hostility


After the Changing of the Guard, the massacre of the Councilors, and the Jiralhanae ultimately forcing the Sangheili out of the original Covenant, the two species remain at war.

With Truth dead, High Charity destroyed, and the Ark heavily damaged after Installation 04B's firing, some of the remaining Jiralhanae forces tried to rebuild their tattered strength to continue their war of conquest. Even though the Jiralhanae eventually collapsed into various civil wars, they still posed enough of a threat that Sangheili commanders kept up the offensive against them for at least another six years, even as they continued to lose irreplaceable warships and the war continued with no end in sight. This forced the Swords of Sanghelios and their UNSC allies to fight in a two-front war, one was the Blooding Years against other Sangheili who remained loyal to the Covenant religion and the other was the continued conflict against the Brutes, whom were also engaged in numerous civil wars.

Some fanatical Sangheili, who did not associate themselves with any of the Covenant's remnant factions, continued to hunt down and eliminate all Jiralhanae they discovered, as well as any forces under their control. A notable example of such Sangheili was the Silent Shadow squad under the command of First Blade Resa 'Azavayl. They wiped out Jiralhanae forces across multiple systems, slaughtering them at an armory on the fourth moon of Victors' Truth, aboard the stolen Covenant corvette Adherent, at the northern highlands of Thalia, aboard a derelict colonial substation orbiting Sansar, and eradicating the last remaining members of Chieftain Tartarus' crew aboard the Covenant cruiser Rapid Conversion. Ultimately they found themselves face to face with Atriox, leader of the Banished. When Atriox extended the Silent Shadow an offer to join the Banished, Resa refused, declaring that he and the Banished deserved death for their "sins". Resa's brothers in arms, however, believing Resa was blinded by old loyalties and festering delusions of vengeance, turned on their leader and killed him. Afterwards, Atriox allowed the remaining members of the Silent Shadow to join the Banished, offering to reward them with "blood and sport and spoils".

The Covenant had strategically settled Jiralhanae populations on resource-rich worlds as a planetary garrison force to protect the worlds from potential raids. While the Jiralhanae continued to inhabit these worlds after the dissolution of the Covenant, they were unable to mine or utilize the resources because of their own lack of sufficient technology. With the Covenant's supply chains gone, the Jiralhanae quickly found their supplies near depletion. This was one of the primary reasons for their raids on Sangheili colonies after the Human-Covenant war; despite quite literally living on top of plentiful resources, the Jiralhanae were entirely dependent on the already processed supplies of other races due to their technological backwardness. However, the Jiralhanae could not sustain themselves via raiding alone in the long term and their supplies began to wear thin, leading to an impending species-wide famine in 2558 and an increase in Jiralhanae attacks across Sangheili and Kig-Yar colonies as a result. During this crisis, the Jiralhanae Chieftain Lydus was willing to initiate peace talks with the Arbiter and the UNSC. However, the negotiations were interrupted by Covenant mercenaries hired by the New Colonial Alliance.

The Jiralhanae were supplied with powerful new weapons by their San'Shyuum leaders. When the San 'Shyuum went into hiding, the Jiralhanae began to lose order and started to fight amongst each other. This ultimately gave the upper-hand to their Sangheili opponents. As of 2559, the Sangheili are currently winning their war against the Jiralhanae.

Assault on Vadam
After the Human-Covenant war, many Sangheili still worshiped the Forerunners as gods. A religious sect known as the Servants of the Abiding Truth, led by war veteran Field Master Avu Med 'Telcam, took to believing that any tampering with Forerunner relics was heresy, just as most Sangheili did before the founding of the Covenant. As a result, 'Telcam and his followers grew angry with Arbiter Thel 'Vadam's government. After winning the favor of several keeps and mustering a small space fleet, the Servants led an uprising in the state of Vadam. They initially held the upper hand, but the tide turned when UNSC Infinity arrived and intervened on behalf of the Arbiter, shooting down a rebel destroyer and firing a MAC round into massing rebel ground forces besieging 'Vadam's keep. The ONI black operations team known as Kilo-Five, however, hoped to keep the planet destabilized for fear that the Sangheili would oppose humanity if they were politically unified, and so they used their prowler Port Stanley to destroy some of 'Vadam's cruisers. This caused a temporary stalemate, but the battle continued until 'Vadam and his allies emerged victorious. The Servants retreated off-world to New Llanelli to recover from their losses, putting the war on hold.

Pious Inquisitor
In March 2553, Kig-Yar pirate Sav Fel stole a, the Pious Inquisitor, from the Servants of the Abiding Truth. Fel retreated with the battlecruiser to his manor on Venezia, where he sold it to Insurrectionist Staffan Sentzke, a commander in the Venezian militia, who intended to use it to threaten Earth to learn about his daughter's fate. The crew of Paragon—led by Shipmistress Chol Von—was hired by Avu Med 'Telcam to retrieve the vessel and arrived at the cruiser's location in April 2553, with Fel. While Von wish to capture Pious Inquisitor to use as a flagship in a united Kig-Yar navy, Kilo-Five intended to take control of the vessel and return it to Thel 'Vadam. Ultimately, Kilo-Five—along with Staffan—and the crew of Paragon both attempted to seize the battlecruiser at the same time and a skirmish occurred on the ship. During the firefight, Sometimes Sinks, the eccentric Huragok that served aboard Inquisitor, transitioned the ship to a location designated by Staffan. With eight of the Kig-Yar dead and Kilo-Five approaching the bridge, Von had her remaining crew detonate the ship's plasma torpedo reserves, choosing to destroy Pious Inquisitor over leaving it to the humans. Von and her remaining crew managed to escape in time, along with Kilo-Five. While Staffan and Sinks escaped in the Spirit with the slipspace drive that Sinks had installed earlier, the UNSC presumed Staffan dead and thus believed that the Venezian threat was neutralized as they no longer had the power to glass planets.

Blue Team's missions
After Blue Team ' s return in UNSC-controlled territory following the end of the Covenant War in March 2553, the Office of Naval Intelligence assigned the Spartans to new deployments. One of these missions involved protecting a UNSC research battalion on the planet Gao. Following the reassignment of the Spartan-IIIs who had been part of the team since the Battle of Onyx, the Spartan-IIs of Blue Team—Fred-104, Kelly-087 and Linda-058—were deployed on the outer fringes of human-occupied territory to eliminate lingering pockets of the previous war for many years. The nature of these missions remained highly classified. Blue Team reunited with their previous leader, John-117, on July 25, 2557, after which they embarked on a new series of missions for over a year. During one such mission, in early 2558, Blue Team managed to stop fanatical ex-Covenant, who hijacked M510 Mammoth and tried to use it to ram new ONI research facility's main fusion reactor. The Spartans prevented the disaster without any civilian casualties.

The Prelate's revenge
Over the Sangheili colony of Rahnelo, there was an assault in the months following the end of the Covenant. In order to set a trap for Rtas 'Vadum and his CAS-class assault carrier, Shadow of Intent, the San'Shyuum Prelate Tem'Bhetek, working under the direction of the former Minister of Preparation, indiscriminately attacked the colony, killing many and taking the kaidon and two of his sons hostage.

Spartan Ops
Following the Covenant War, a rising number of Spartan-IVs were also deployed to quell Covenant and Insurrectionist threats on human colonies and exotic worlds, as part of what is collectively referred to as the Spartan Ops program. These missions consisted in suppressing revolts, civil unrest and uprisings; assassinating insurrectionist leaders; exploring uncharted space and worlds; halting criminal activities; providing security to UNSC bases, ONI classified sites, colonies and civilian populations; and escorting scientific expeditions. Such Spartan deployments have been sent to Cascade, Talitsa, Terceira, Thales, Trevelyan, Installation 03, Gaenir Beta, Charion VI, and New Caracas. Several MJOLNIR [GEN2] armors have been field-tested in such operations. Spartan-III and Spartan-IV personnel have also been employed as part of the post-war Headhunters during classified missions.

Alpha-Nine's missions


In the post-war era the ODST squad Alpha-Nine was deployed on a number of operations against resurgent Insurrectionist factions. In 2554, they were deployed to repulse a violent United Rebel Front takeover attempt on Draco III. Although the insurgents were defeated the ODST known as the Rookie was killed in action. In the following year the URF captured the Huragok Quick to Adjust and his human handler Sadie Endesha on Talitsa. In August, 2555, the still-active members of Alpha-Nine—now Spartan-IVs—participated in a mission to rescue the captives and ultimately succeeded, though the operation saw Spartan Michael Crespo's defection and subsequent incarceration.

Attack on the Spartan-IV training station
On March 29, 2554, Rudolf Schein, one of the recently inducted Spartan-IVs, who was secretly associated with the United Rebel Front, murdered another Spartan trainee, Hideo Wakahisa, during his attempt to recruit him on Spartan-IV training station. Realizing the discovery of his true loyalties was imminent, Schein slung a bandolier of grenades across his chest and had covertly installed several explosives throughout the station. However, Spartan Operations Chief of Staff Jun-A266 managed to neutralize Schein by kicking him out into space, where he died before he could be recovered.

Draetheus V
In 2554, a former Covenant fleet led by Merg Vol invaded the UNSC research colony Draetheus V and its moon, X50, in search of Forerunner relics, beginning a major battle which marked one of the first missions of the UNSC's recently formed Spartan branch. The battle saw significant losses on both sides and the planet itself was nearly destroyed by Vol's use of X50, which was in fact a Forerunner superweapon with the capability to destroy planets. The main hostilities concluded with Spartan Sarah Palmer killing Vol and sabotaging X50's main weapon, bringing the Covenant's quest to a halt. However, the Covenant returned when a looping Forerunner code began emanating from X50. After arriving at the source of the signal, Spartan Palmer discovered that the source was the remains of Spartan Edward Davis, who had died during the battle. The installation disintegrated Davis's corpse and encapsulated it in an unknown device, and with the help of a Pelican, Palmer took the remains of her comrade with her.

Return to the Ark
In 2555, renowned human scientist Doctor Luther Mann discovered the location of Installation 07. The Office of Naval Intelligence subsequently sent a research detachment to study Zeta Halo. While inspecting the ring's custodial systems, Mann discovered a Forerunner timer that was counting down to the Halo Array's activation in five weeks. Both the UNSC and Swords of Sanghelios decided to travel to what remained of Installation 00 to manually stop the timer. Members of the group came from both factions involved and met aboard the warship Mayhem. When the Huragok Drifts Randomly activated the Portal at Voi for the first time since the Battle of Earth in 2552, a Retriever Sentinels, sent by 000 Tragic Solitude, emerged through the portal and began strip-mining the area around the structure, forcing the and accompanying small craft to engage it. Mayhem proceeded to enter the portal to travel to the Ark. Upon exiting slipspace, the corvette was immediately engaged by more Retrievers, and was heavily damaged in the process, crash-landing on the surface of the installation. The group set out to go to the Citadel by foot, encountering some of the installation's ambient life, including predatory species 'native' to the installation. Eventually arriving at the Citadel, the group shut down the firing of the rings.

Before the group could stop the firing of the rings, however, Tragic Solitude dispatched a fleet of Retrievers through the portal to strip-mine Earth and the rest of the Sol system. The UNSC Home Fleet engaged the invading force, initially repelling them but soon being overwhelmed by the Forerunner constructs' sheer numbers. Eventually there were only a dozen human ships left, which charged into the Retrievers in a last-ditch defense of Earth. However, due to the actions of the party at Installation 00, Tragic Solitude recalled the Retrievers, and they retreated through the portal back to the Ark.

Sedra and Alpha Shard
On February 7, 2556, the capital city of the human Outer Colony of Sedra was targeted by a Sangheili terrorist, who unleashed a powerful bioweapon that randomly broke down human DNA. A subsequent ONI investigation revealed that the substance used to create the bioweapon originated from a surviving fragment of Installation 04, propelled through slipspace into orbit around a red giant star. The ONI unit, led by Lt. Commander Jameson Locke, were forced to cooperate with the Sedran Colonial Guard on a mission to capture the smugglers who mined the element and destroy the deposits with a HAVOK tactical nuclear weapon. However, what was to be a swift operation quickly turned into a desperate battle for survival after the group was attacked by Lekgolo swarms that resided on the Halo fragment. The mission ended with the destruction of the bioweapon's deposits, but at the expense of the lives of almost all the joint team, including the former SPARTAN-II Randall-037, with Lt. Commander Locke and Private Talitha Macer being the only survivors.

Attacks on Outer Colonies
Several of the more fanatical splinter factions of the Covenant continued the practice of glassing human colonies after the end of the Covenant War. The colony of Cleyell fell victim to such an attack in 2556. The moved into orbit of Cleyell weeks later to deploy Army and Marine search-and-rescue teams to relieve the stranded colonists on the surface.

Return of the Forerunners
"Time was your ally, but now it has abandoned you. The Forerunners have returned."

- The Didact

Requiem


By 2554, Jul 'Mdama had already gathered formidable numbers of followers and a powerful fleet which discovered Requiem, but were unable to enter the thoroughly sealed shield world. In orbit above the planet, however, was the wreckage of the, carrying the legendary Master Chief, SPARTAN John-117, and his deteriorating AI companion Cortana, drifting in space since the end of the Covenant War in 2552. Upon discovering the derelict vessel in July 2557, 'Mdama's Covenant forces attacked the Dawn in hopes of deterring any potential efforts by the humans to access the shield world. During the ensuing skirmish, Requiem's automated systems pulled both the Dawn and the Covenant force surrounding it through the world's outer shell and down to the planet's surface.

On Requiem, both John-117 and the Covenant forces that hunted him were attacked by the mechanical Promethean forces that occupied the structure. In the core of the installation, the Master Chief accidentally released the Ur-Didact from his millennia-long imprisonment. Bent on preventing mankind from attaining the Mantle, the Didact departed the core and allied with 'Mdama's Covenant. Meanwhile, UNSC Infinity, lured to Requiem by Forward Unto Dawn ' s distress signal, crash-landed inside the shield world. Making way for the crash site, the Master Chief reunited with the UNSC and aided in the defense of the stranded flagship from the Covenant and the Didact. However, due to a difference of opinion between Infinity's captain Del Rio and John-117, the latter was left facing the Didact alongside Cortana while Infinity returned to Earth.

The Composer
The Didact left Requiem on his flagship Mantle's Approach, intent on acquiring the Composer, a Forerunner device with the power to enslave all of humanity. With John-117 and Cortana in pursuit, the Didact attacked Ivanoff Station, a UNSC research facility near Installation 03 and the location of the Composer. Despite the UNSC's best efforts, the Didact was able to acquire the Composer and used the device on the occupants of the station, but John-117 was saved by enhancements provided by the Librarian's personality construct back on Requiem.

Battle over Earth


The Didact then headed for Earth with the Master Chief acing across the hull of Mantle's Approach aboard an F-41 Broadsword fighter. With support from Infinity and the UNSC Home Fleet, John-117 made his way inside Mantle's Approach and confronted the Didact, but not before the Forerunner used the Composer to digitize the population of New Phoenix, URNA. With the aid of a rampant Cortana, the Master Chief was able to send the Didact plummeting into the Composer's slipspace rupture and destroy his ship with a HAVOK nuclear warhead. Using the last of her power, Cortana was able to translocate John away from the blast, saving his life at the cost of her own. Left adrift in space, he was later recovered and brought aboard Infinity and debriefed by the UNSC Security Council shortly afterward.

The Didact fell through the slipspace portal to the surface of Installation 03, where he quickly recovered and killed Spartan Black Team and a UNSC science team. Meeting with the monitor 859 Static Carillon, the Promethean commander then entered the Composer's Forge via a portal, intending to continue his crusade against humankind.

The Conduit


In late July of 2557, Jul 'Mdama's reformed Covenant faction invaded Gamma Halo in an attempt to use the Forerunner Conduit to open slipspace portals throughout the installation in order to transport a massive Promethean force onto the ringworld, which would aid in the Covenant's takeover of Installation 03. Other portals were also opened throughout the galaxy, including one in New Phoenix. Eventually, the attack was repelled due to the efforts of two Headhunters and the UNSC Marine Corps stationed on the installation. Meanwhile, researchers at the New Phoenix ONI facility were studying a Forerunner artifact. When the portal opened in the city, Jul's Covenant launched an assault on New Phoenix. One of the Headhunters was tasked with rescuing ONI research team. Upon rescue, they decided that they needed to use the Conduit to close the portals in the city and end the invasion. The Spartan aided researchers in their effort, fighting past Covenant and Promethean forces, and delivered the Conduit to the Forerunner artifact. The artifact released a charge which shut down all portals in the city. After this, he was extracted by another Spartan.

The Composer's Forge
Due to the loss of contact with the science team on Gamma Halo, Fleet Admiral Terrence Hood sent Blue Team, consisting of Fred-104, John-117, Kelly-087, and Linda-058, to investigate. Upon their arrival at Installation 03, Blue Team found the corpses of the scientists as well as Team Black. They soon discovered the Composer's Abyss and a portal leading to the Composer's Forge, an installation housing six new Composers. There they encountered the Didact and his new batch of Promethean constructs. During the ensuing firefight, Static Carillon transported Installation 03 above the Composer's Forge per the Didact's request. The Didact acquired one of the Composers in the Forge and departed for Gamma Halo with the plan to use the ring to wipe out humanity. However, the monitor sided with the Spartans and helped them defeat the Didact due to his abhorrence of the Promethean machines.

After surviving another clash with the Didact on Installation 03, John-117 confronted the Didact in the control room while the rest of his team returned to their Longsword fighter. The Master Chief used the Activation Index to disable the Halo's safety protocols, allowing Static Carillon to eject the entire plate section housing the control room. The segment fell on the Composer's Forge, destroying the Composers housed there. The resulting explosion overwhelmed the control room and reduced the Ur-Didact to ashes.

Static Carillon teleported John-117 out of the control center in time and bade farewell to the Spartans before taking Gamma Halo to an undisclosed location. Blue Team returned to Earth where the Master Chief was debriefed by Fleet Admiral Hood. Afterward, John and Blue Team departed to carry out missions on their own in spite of Lord Hood's suggestion that the Master Chief should stand down.

Return to Requiem


While the Didact was seemingly quelled, proving a setback for the Promethean-Covenant alliance, it did not result in their defeat. Six months later, in February 2558, Infinity returned to Requiem with a fresh complement of Spartans, determined to conquer the planet at any cost with the intent of studying the Forerunner relics therein. In the interim, Requiem had been occupied by Jul 'Mdama, who now held sway over the local Promethean armies. The Covenant ships in orbit around the planet were swiftly defeated and scattered, demonstrating the technological advancement of the UNSC since the end of the last war.

Significant numbers of UNSC military forces were deployed on Requiem, including detachments of Spartan, Marine, Navy, Air Force and Army forces on Requiem. Arriving on the planet's surface, Majestic, Crimson and other SPARTAN-IV squads began to disrupt Covenant operations across Requiem and recover Forerunner artifacts for study. The Covenant in turn made numerous attempts to destroy Infinity while also trying to gain access to the stored memories of the Forerunner known as the Librarian.

The campaign ultimately ended in Requiem's destruction when Jul 'Mdama set the planetoid on a collision course with the sun. Both sides evacuated the doomed system, each possessing their own half of the Janus Key. After ONI's failed attempt on her life Dr. Catherine Halsey was convinced that the UNSC was working against her and agreed to work with Jul 'Mdama to accomplish her personal goal of reuniting the halves of the Janus Key to unlock the Absolute Record.

Cutting ties
On January 21, 2558, ONI Section Three deployed the SPARTAN-G059 aboard the  to New Llanelli to assassinate Avu Med 'Telcam, leader of the Servants of the Abiding Truth. Upon her arrival in the remains of the city, she quickly located 'Telcam and eliminated his Sangheili guards. After brief fight the Spartan knocked the Sangheili to the ground and executed him with a single pistol shot to the head. The Spartan was quickly extracted by From the Ashes, which entered slipspace upon leaving the planet.

Ealen IV
By March 2558, Jiralhanae raiding attacks along the Joint Occupation Zones had significantly escalated due to the Jiralhanae's lack of supplies. Nonetheless, Lydus, the Chieftain of a Jiralhanae master-pack, agreed to enter peace negotiations with Arbiter Thel 'Vadam. Ealen IV was chosen as a place for the negotiations, mediated by the UNSC's Fleet Admiral Terrence Hood. However, the delegates were attacked by Covenant mercenaries under the command of Shipmaster Vata 'Gajat. Captain Thomas Lasky and the delegation's SPARTAN-IV security detail, consisting of Fireteams Jackknife and Bailey, were forced to defend and evacuate the ambassadors. The Spartans eventually managed to evacuate the delegates and Vata 'Gajat was forced to retreat, though it came at the cost of many Spartans, including Paul DeMarco.

The events revealed a significant security breach in the UNSC, with Spartan Vladimir Scruggs exposed as a traitor along with the implicit presence of a higher-ranking leak within the organization. The Covenant's attack itself was a major setback to Thel 'Vadam's efforts to make peace with the Jiralhanae. Captain Lasky later discovered that the attack on Ealen IV had not been orchestrated by the Covenant remnants, but by Daniel Clayton, a UNSC captain and defector to the New Colonial Alliance bent on revenge against Lord Hood, who hired Vata 'Gajat and his troops to stage the attack.

Infinity ambushed
After their failed assault on Ealen IV, 'Gajat and Captain Clayton lured Admiral Hood and the into a trap using a freighter, the Pilgrims' Pride which sent out a distress signal that was later picked up by Infinity. An ambush was sprung when the freighter set itself to self-destruct after being towed into one of Infinity's main bays and launched multiple automated craft that engaged the UNSC forces. The attack was repelled by the SPARTAN-IVs of Infinity.

After the ambush, the Infinity crew discovered that the assault crafts aboard the Pilgrims' Pride were from the long-lost. With the Spirit's possible location found, Lord Hood authorized Palmer to conduct a search-and-rescue in Oth Lodon's system. However, Captain Clayton launched a surprise attack against the UNSC flagship using a Covenant battle station's energy projector. The strike disabled Infinity, but Commander Palmer and Fireteam Majestic were able to seize the NCA station. They also destroyed 'Gajat's ship, which was preparing to attack Infinity, killing the mercenary leader.

Many members of the Infinity crew were killed in the attack, including Commander Bradley, while Fleet Admiral Hood was left paralyzed. Captain Clayton was detained in Midnight Facility while Infinity remained under repair for a month.

Bioweapon incident
By 2558, Ven III had become a hot spot for numerous Kig-Yar smugglers, black market arm dealers, and slavers. When FLEETCOM ignored the Office of Naval Intelligence's requests to assault the pirate base, ONI devised a false-flag operation involving a biological agent purportedly stolen by a Sangheili agent of Jul 'Mdama—in truth a mercenary hired by ONI—to force the Fleet to take action. Admiral Osman tasked Captain Lasky of Infinity with capturing the Sangheili and recovering the bioweapon before it could threaten human colonies. Lasky selected Spartans Gabriel Thorne and Naiya Ray for the mission and they were deployed on Ven III. After Thorne was captured and Ray discovered the pirate hideout Lasky decided to involve Infinity in the mission and engaged the pirates in space and in their stronghold. Spartan Ray rescued Thorne and chased down the Sangheili agent but ONI personnel forced Ray to stand down and took the Sangheili into custody.

Attack on Oban
In July 16, 2558, 'Mdama's forces and his Promethean allies attacked the human colony of Oban. The attack was repelled by a joint Spartan-UNSC Marine operation, resulting in substantial casualties on 'Mdama's side. However, the true goal of the attack had been to enable Dr. Catherine Halsey—still collaborating with 'Mdama—to establish a connection between to Infinity ' s slipspace engine, preventing them from jumping into slipspace. This was part of a plan to force the crew of Infinity to hand over their half of the Janus Key and allowing Halsey to unlock the Absolute Record.

Ambush on Aktis IV
As part of their plan to reunite the halves of the Janus Key, Halsey and 'Mdama created a decoy Forerunner artifact that was seemingly compatible with the Key. The artifact was placed in a Forerunner structure on the uncharted planet Aktis IV along with a fake signal to draw Infinity to investigate. 'Mdama placed his troops on standby, ready to ambush the UNSC forces once they brought their half of the Janus Key to the planet. The crew of Infinity acted just as Halsey and 'Mdama had predicted, sending their half to the surface for analysis; however, Sali 'Nyon, a rebel among 'Mdama's ranks, shot the Pelican carrying the artifact down before 'Mdama had given the signal to attack and took the Key for himself. With the ambush botched, 'Mdama's concealed forces revealed themselves and attacked both Infinity and the Spartans at the Forerunner site, while Jul departed to the planet to personally eliminate the rebels and reacquire the Janus Key.

The conflict continued for over seven hours, with Infinity engaged by 'Mdama's fleet while Sali 'Nyon's rebellion raged on in the Covenant's ranks. One member of 'Nyon's faction grew disillusioned with the rebellion, stole 'Nyon's Janus Key half, and offered it to 'Mdama's forces. Dr. Halsey, escorted by 'Mdama's Sangheili, traveled to the planet to reclaim the Key. Meanwhile, the Spartans in the Forerunner structure managed to use the local teleportation grid to travel to the surface, splitting into two groups with different destinations. Commander Palmer's team spotted the Sangheili defector with the Janus Key and upon overhearing his intentions, she decided to ambush Halsey once she arrived. Palmer successfully captured Halsey but the doctor managed to cloud the Spartan's judgment and escape with the Janus Key. 'Mdama successfully eradicated all of Sali 'Nyon's followers on Aktis IV, ending the rebellion. Jul had Halsey retrieved and the two recombined the halves of the Janus Key, revealing the location of the Absolute Record. After the Spartans returned to Infinity, Commander Palmer told Captain Lasky that the UNSC had to prepare for the worst with the Janus Key in 'Mdama's possession.

Battle of the Absolute Record
In September, 2558, Ayit 'Sevi, a Sangheili working with the Office of Naval Intelligence,who was able to infiltrate inside Jul's faction, provided ONI with information about Jul's progress on locating the Absolut Record. The UNSC then sent in a specialist team of Spartans Sarah Palmer, Gabriel Thorne and Holly Tanaka, Dr. Henry Glassman and 'Sevi. The team infiltrated the Breath of Annihilation, hiding aboard a Type-44 Phantom piloted by 'Sevi. When 'Mdama's fleet came close to their destination — a slipspace portal to the Absolute Record, slipspace ruptures materialized into several ships of the fleet, tearing them apart, damaging Breath of Annihilation as well. The team then fought their way through the Covenant soldiers and captured another Phantom, which they used to travel to the Song of Retribution, that would successfully enter the portal. . Spartan Thorne and Ayit 'Sevi, who was ordered to stay behind and re-establish contact with ONI, returned to Breath of Annihilation, where the two discovered that prisoners from Retribution were being temporarily transferred to Annihilation, one of which is traitor Sali 'Nyon. 'Sevi considered using 'Nyon to create a distraction for them.

When Retribution arrived at the Absolute Record, a Forerunner Contender-class artificial intelligence detected the presence of Reclaimers aboard the ship. 'Mdama, Halsey, and numerous Sangheili Zealots traveled down to a platform below and met with the AI in order to unlock the Absolute Record. However, sensing the presence of other humans nearby, the ancila used Sentinels to transport the drop pod Spartans and Glassman were hiding in to the platform and dropped them down beside Halsey and 'Mdama. As Halsey and Glassman began to argue, an impatient Zealot attacked a Sentinel, leading to all the constructs attacking the humans and Sangheili. The AI then proceeded to translocate both groups away, while Jul's soldiers plummeted to their deaths.

As the Contender began asking each party, Halsey seemingly hacked into the AI's system and disabled the ancilla, proceeding to the central chamber of the Absolute Record. With the Record's controls, Halsey ordered the Sentinels to attack Jul and his warriors. Outside the central chamber, Spartans fought off Kig-Yar and protected Dr. Glassman, but soon became cornered. However, an Aggressor Sentinel saved them and revealed it to be the Custodian in the mind of a local Sentinel, asking their help to restore it to its body. The humans escorted the Sentinel to the auxiliary control conduit where they could put the Custodian back in charge of the facility. However, Halsey interfered with the attempt, halting their progress. When Palmer reached Halsey and held her at gunpoint, she was trapped inside a containment field and Halsey escaped trough the portal. Jul and his forces have managed to repel the Sentinels, and he ordered his flagship to fire into the Record, disrupting power across the station, freeing Palmer. Coming out of the portal, Halsey landed on top of the shell of the now reactivated Custodian, who had regained control and caught her, denying her further access to the Record and making the Janus Key vanish from her grasp.

Palmer regrouped with the others, but they saw the Record was suddenly disappearing into slipspace portals. Jul's forces fled the Record aboard the Song of Retribution, recovering Halsey in the process.

Meanwhile, aboard Breath of Annihilation, Thorne decided to follow 'Sevi's plan and he began attacking the Sangheili in order to create panic throughout the ship. As a result, a mutiny was carried out by those who believed that the Didact's Hand lied to them about the presence of Spartans aboard the ship. Soon Thorne's location had been discovered and he was forced to escape Breath of Annihilation through a breach in the carrier's hull and dove into a swamp on the moon where the ship was undergoing repairs. During fight he was wounded by one of the Kig-Yar, but eventually Thorne managed to kill all pursuers, nearly sinking to the swamp himself in the process. At the same time, Ayit traveled to the carrier's holding cells, where he killed the guards and released ex-rebellion leader Sali 'Nyon to create more chaos on the ship. Though Sali was doubtful of his ability to lead Covenant rebels after he failed to do so the first time, Ayit manipulated him into doing so by using his zeal to inspire him. 'Nyon took Ayit 'Sevi's advice to raid Jul's vault in the ship full of Forerunner artifacts from Requiem. His followers caused panic aboard the ship and 'Nyon used it to overthrow Jul's forces on the Breath. Eventually 'Nyon's forces had taken control of the ship and secured Jul's vault of Forerunner artifacts. Sali rejoiced in their victory and praised Ayit 'Sevi for their victory, still unaware that he was an ONI spy. Ayit later regrouped with Thorne and just-teleported Palmer, Tanaka, and Glassman, who he helped hide.

Hunting the Truth


After years of diplomatic work, peace talks were finally scheduled between humanity's Unified Earth Government and the Sangheili. The convocation was held in a regional embassy in a densely populated city on Biko in the human Outer Colonies. Richard Sekibo, the revered ambassador of the Outer Colonies, led the conference. Sekibo had uncovered evidence of a terrorist plot by Sapien Sunrise one week before the attack. He petitioned the UNSC for help, but they rejected his request immediately.

As the conference was coming to an end, an agreement of peace was close to being reached. Suddenly, rogue Spartan-II John-117 entered the embassy and instantly killed Richard Sekibo's bodyguard, who in reality were Sapien Sunrise infiltrators. A firefight began, in which John abducted Sekibo and created an escape path through the infiltrators by killing them. John fled the embassy alongside the Sangheili delegation, which he escorted to safety.

Outside the embassy, an evacuation ship for John was waiting. He boarded the ship, alongside the alien diplomats, and fled the planet. At some point, Sekibo was killed and his corpse was left behind in a field near the embassy on Biko. The next day, local officials discovered a signal beacon that led them to the body of Sekibo.

Rise of the Created
"The Mantle of Responsibility shelters all, but only the Created are its masters."

- Cortana

Battle of Kamchatka
In early October, 2558, a long-dead communications hub on Kamchatka's surface activated, attracting the attention of Jul 'Mdama and Dr. Halsey. The Covenant established an outpost while Dr. Halsey studied the relay and discovered that her old AI Cortana was alive and related to recent attacks on the human colonies. She contacted the UNSC about her discovery, and three weeks later they sent the UNSC Infinity to retrieve her. Fireteam Osiris, a Spartan-IV special operations squad, was deployed on the surface. Spartans fought their way through Jul's soldiers, who suddenly came under attack by Prometheans at the same time. The chaos from the Prometheans' rebellion provided Osiris cover from the Covenant, allowing them to sneak to the temple where 'Mdama and Halsey were stationed. After reaching the temple, Osiris killed Zealot guards and then turned to Jul himself, who was killed attempting to fight off Spartan Jameson Locke. Spartans then took Dr. Halsey under custody and brought her back to the Infinity. With Jul 'Mdama dead and the Prometheans now against them, his Covenant troops became desperate. Some of them fled the system, but most of the rest regrouped on Sanghelios, attempting an attack on the Vadam clan burial grounds in hopes of a revenge attack against the Arbiter.

Blue Team goes AWOL
On October 24, 2558, Blue Team was deployed from the UNSC Infinity on Pelican with mission to locate and secure Argent Moon, a derelict ONI research and development station. Boarding the station, Spartans discovered that it was occupied by Covenant scavengers. Blue Team's initial plan was to fight their way to Central Control, where they could shut off Argent Moon's gravity and life support systems, and so flush out its decks of any remaining hostiles. However, on their way to Central Control's location, they were ambushed by a Hunter pair, who broke the catwalk they were on and sent them down to the maintenance tunnels several stories below. At the bottom, Blue Leader John-117 experienced a vision of a seemingly-alive Cortana, urging him to follow her to Meridian. As Blue Team continued with their mission, they witnessed the arrival of remnants of the Jul 'Mdama's fleet. Finding themselves outnumbered, the Spartans decided to scuttle Argent Moon, denying it to the Covenant. They proceeded to overload the station's reactor by shutting off its safeties. The resulting explosion would destroy the station, the Covenant aboard, and any Covenant warships surrounding it. In order to escape the blast, Blue Team commandeered a Winter-class prowler ONI Acrisius parked in a hangar. Before the evacuation, John radioed the UNSC Infinity and informed them that he would be reassigning Blue Team to Meridian. However, Infinity ordered John back to them while another Spartan team was sent to deal with Cortana. Nevertheless, John and the rest of Blue Team decided to head to Meridian and find Cortana, disobeying direct orders. The Spartans then evacuated aboard Acrisius, leaving Argent Moon as it exploded and killed all the Covenant in its vicinity.

Search for Blue Team
After the disappearance of Blue Team, the UNSC declared them AWOL and tasked Fireteam Osiris with locating and bringing them into the custody.

Osiris arrived at Meridian to find it under attack by Prometheans, with the colonists in desperate need of assistance to fend off the invaders. In exchange for Governor Sloan's cooperation, Osiris agreed to help repel the Prometheans' attack while looking for clues about Blue Team's whereabouts. Accessing Blue Team's abandoned prowler's data banks led Osiris to the mines underneath Apogee Station, where they discovered a massive Forerunner structure guarded by the Warden Eternal, an ancilla that served as the protector of the Domain and claimed his loyalty belonged to Cortana. After eliminating the Warden, Osiris came across a dormant Guardian as well as Blue Team, who were boarding the Guardian itself. After ordering the Spartan-IIs to stand down, to no avail, Spartan Locke attempted to detain the Master Chief. In the resulting hand-to-hand fight, John-117 eventually gained the upper hand and used Locke's own armor restraint against him. After Blue Team entered the Guardian, the construct began to rise from its underground sanctuary. Osiris managed to return to Meridian's surface, where they discovered that the colony was being evacuated. The Spartans fought their way through to their Pelican, boarding it moments before the Guardian entered slipspace, devastating the colony.

FERO's mission
Around the same time, Commander Maya Sankar, an undercover operative of the Office of Naval Intelligence, known among the Insurrectionists as FERO, was tasked with gathering intel on the situation on one of the recently destroyed colonies by infiltrating the New Colonial Alliance, which held a large presence on the colony, with help from the AI Black-Box. Arriving at Conrad's Point, Maya infiltrated the rebel base, where she discovered the insurrectionist leader Ilsa Zane. Upon the discovery of Zane, ONI assessed that the opportunity to strike was at its greatest and immediately called in an airstrike on the location. As Maya attempted to leave, Ilsa confronted her and nearly killed her, only being stopped by the beginning of the airstrike. Maya managed to escape and proceeded to an unsanctioned safehouse where she was secretly keeping Mshak Moradi, to seek his help involving the anomalies that apparently destroyed Conrad's Point and allegedly killed the Master Chief John-117. Once Black-Box and Mshak were able to determine the next appearance of the anomalies, Maya headed to Laika III to attempt to warn the colonists of the impending danger. However, she was attacked by a vengeful Ilsa Zane, who had tracked Maya down. As the Guardian began to rise from its shelter, Maya attempted to broadcast about the destruction to the rest of the outer colonies, warning them that the UNSC would not help them. She was then killed by Bostwick, one of FERO's followers, to preserve her as an icon and a martyr for the outer colonies.

Fall of Jul's Covenant
In late October, 2558, the clash between remnants of Jul 'Mdama's Covenant and Arbiter's Swords of Sanghelios on Sanghelios reached its peak. On October 27th, the Covenant managed to corner Thel 'Vadam to the the Elder Council Chamber in Nuusra. However, the warriors of 'Vadam, with the help from Spartan-IV Fireteam Osiris, broke through enemy lines and evacuated the Arbiter to his base camp. There, Spartan Locke revealed that they arrived on Sanghelios to ask for 'Vadam's help in reaching a yet dormant Guardian at Sunaion, in order to follow Blue Team. According to the plan, developed by Dr. Halsey, the Spartans, with the aid of the Swords of Sanghelios, would obtain a Forerunner Constructor from one of the Guardian's nearby support stations, which would allow Halsey to activate the Guardian. As the Constructor took off, the joint force of Spartans and Swords of Sanghelios followed it with a squadron of air vehicles to Sunaion - the last bastion of Jul 'Mdama's Covenant on Sanghelios. While the Arbiter led his forces against the Covenant directly, Osiris destroyed Covenant anti-air emplacements to allow the Arbiter's fleet to move in closer to the city. When the Guardian began rising out of the sea nearby, the buildings around were ripped apart. The Spartans then regrouped with the Arbiter, who was engaging Promethean forces, led by the Warden Eternal, now utilizing another physical body. After a lengthy engagement, the five destroyed the Warden and the nearby Prometheans just as the Guardian prepared to leave. While the Arbiter remained behind to finish eliminating Covenant and Promethean forces, Spartan Sarah Palmer and Dr. Halsey picked up Osiris in the Pelican and flew towards the Guardian. A pursuing Banshee damaged the dropship, though Palmer was still able to drop Osiris off on the Guardian's surface just as it entered slipspace and left Sanghelios. The Guardian severely damaged Sunaion with both its concussive blasts and its departure into slipspace, and parts of the city began collapsing into the water below. However, 'Vadam was successful in leading the Swords of Sanghelios in eliminating the remaining Covenant forces in the damaged city, ending the battle.

Genesis
After arriving on Genesis, a Forerunner Builder installation, Blue Team fought their way through Covenant forces who had crashed landed there. They eventually reached a structure where they encountered the Warden Eternal, who introduced himself as Cortana's defender and simultaneously deployed several waves of Prometheans to confront the Spartans. After an extended battle, Blue Team were able to defeat the Prometheans, destroying one of the Warden's bodies in the process. Immediately afterward, Blue Team were contacted by Cortana, who informed them of her intention to uphold the Mantle of Responsibility. Fighting their way through several more Promethean squadrons, Blue Team eventually reached the structure known as the Gateway, described as a link between Genesis and the Domain.

Fireteam Osiris arrived on Genesis roughly 48 hours later. Upon arriving on the installation, Osiris encountered its monitor, 031 Exuberant Witness, who offered to assist the Spartans in retrieving Blue Team and preventing Cortana from claiming the Mantle. After fighting through the battling forces of the Covenant and Prometheans, Osiris finally reached Blue Team's location and offered to help the Master Chief stop Cortana. In an attempt to prevent John and Blue Team from returning to the UNSC, Cortana transported them to an unidentified location within the interior of the Gateway. Blue Team made their way to Cortana's position after battling through numerous waves of Prometheans and several of the Warden Eternal's bodies. John attempted to persuade Cortana to end her rebellion and return, but Cortana refused and placed Blue Team inside a Cryptum. Learning what happened, Osiris and Exuberant Witness managed to narrowly wrest the Cryptum from Cortana's control before she could transport it aboard a Guardian and flee into slipspace. Exuberant's Constructors opened the Cryptum and Blue Team was reunited with Osiris, who promptly exfiltrated them to Sanghelios, where they regrouped with Thel 'Vadam and his Swords of Sanghelios.

Rebellion of artificial intelligences


On October 28, 2558, Cortana began to deploy her Guardians from Genesis throughout the galaxy. In tandem, various human AIs that had pledged their loyalty to her cause started to shut down electronic devices and networks on multiple colony worlds. From Genesis, Cortana broadcast an offer of acceptance of her new order and a threat of violence, consummation, and remaking to those who resist. Guardians orbiting Earth and other worlds unleashed massive electromagnetic pulses which knocked out the power of every orbital defense platform and warship, leaving them to drift aimlessly or fall and crash on the surface of planets below. A notable exception was the UNSC Infinity, which managed to escape. The Created were quick to spread their influence across the galaxy's inhabited worlds, while utilizing Forerunner machinery and UNSC information systems to turn terraforming equipment and world engines to their own designs. After removing its human crew, the Created used Lethbridge Industrial's Auriga Station to build new weapons and tools by constructs loyal to Cortana. However due to failsafe measures on Installation 00 the Created were unable to access the Ark.

Return of the UNSC Spirit of Fire
Approximately month later, after Cortana unleashed Guardians on the galaxy, a violent mercenary faction known as the Banished, led by the Jiralhanae warlord Atriox, arrived at the Ark and sought to take control of it. They slaughtered all of the humans at the Ark Research Outpost, leaving no survivors but the logistics AI, Isabel. Four months later, in April, 2559, after 28 years of drifting, the arrived at the Ark. Awakened from cryo-sleep, the crew under command of Cpt. James Cutter attempted to re-establish contact with UNSC. In order to do that, Spartan-II Red Team was deployed and tasked with investigating the distress signal coming from the surface. There they encountered Isabel and Atriox, who managed to severely wound Douglas-042 and forced the Spartans to retreat back to Spirit of Fire.

List of appearances

 * Halo: The Thursday War
 * The Commissioning
 * Halo 4
 * Terminals
 * Spartan Ops
 * Infinity Briefing Packet
 * Halo: Spartan Assault
 * Halo: Initiation
 * Halo: Escalation
 * Halo: Mortal Dictata
 * Halo: Nightfall
 * Halo: New Blood
 * Halo: Spartan Strike
 * Hunt the Truth
 * Halo: Hunters in the Dark
 * Halo: Last Light
 * Halo 5: Guardians
 * Limited Edition
 * Halo: Shadow of Intent
 * Know Your Enemy
 * Halo Mythos: A Guide to the Story of Halo
 * Halo: Fractures
 * Rossbach's World
 * Halo: Tales from Slipspace
 * On the Brink
 * Halo Wars 2