Post-Covenant War conflicts

"Humanity stands as the greatest threat in the galaxy. Refusing to eradicate them is a fool's gambit. We squander eons in the darkness, while they seize our triumphs for their own. The Mantle of Responsibility, for all things, belongs to Forerunners alone! Think of my acts as you will. But do not doubt the reality: the Reclamation... has already begun. And we are hopeless to stop it."

- The Ur-Didact in a speech defending his actions to a group of other Forerunners

Following the end of the Human-Covenant War in 2553, the Unified Earth Government and its United Nations Space Command became involved in a number of new conflicts arising from the immediate aftermath of the war. The hostilities began as irregular warfare between humanity and 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 origins, both eras being intertwined with those of the Forerunners.

In one of the first human-Covenant conflicts after the ceasefire at the end of the Covenant War, one of the Covenant splinter groups attacked the human colony of Draetheus V, seeking to obtain a powerful Forerunner weapon held there. 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battle eventually culminated in the installation's destruction but not the defeat of the Covenant, who had already withdrawn most of their forces from Requiem. Additionally, they managed to capture a significant UNSC asset, Dr. Catherine Halsey, who was seemingly willing to collaborate with 'Mdama. Both the UNSC and the Covenant each acquired half of the Janus Key.

Historical context
"You and I are brothers in many ways... not least in that we faced the Didact before, and face him now, and perhaps ever after. This is combat eternal, enmity unslaked, unified by only one thing: our love for the elusive Lifeshaper. Without her, humans would have been extinguished many times over."

- 343 Guilty Spark to the crew of

While the final year of the Covenant War was marked by clashes for newfound Forerunner artifacts and the revelation of humanity's birthright as chosen inheritors to the Forerunner civilization, yet more significant discoveries would follow in the wake of the conflict. Long-hidden details about the Forerunners and their relationship between humanity began to surface, as did information regarding the yet more ancient and enigmatic race known as the Precursors. These unprecedented findings would have an immediate influence on events in the modern times, acting as driving forces for not only renascent Covenant cults but also forces far more ancient.

Before the Forerunners first built the Halo Array, the human race held a great interstellar empire. During the course of their growth as a civilization, they encountered a terrifying threat: an extragalactic parasite known as the Flood. As the parasite ravaged their worlds and threatened to consume their entire species, humanity fled outwards from their home territory. As they did so, they attacked any Forerunner world where an infection had taken hold, neglecting to warn the Forerunners of the threat in favor of bombarding infected areas immediately. Ignoring their warnings about the dangers posed by the Flood, the Forerunners – led by the Ur-Didact and his Promethean Warrior-Servants – defeated humanity and forcibly devolved their civilization. However, the Forerunners were left vulnerable by the long conflict: their military had been weakened, and all information regarding the mysterious threat that humanity had been fleeing was lost. After millennia of calm the Flood returned and the Forerunners were ill-prepared to fight back.

The Forerunner Builder rate had prepared for this eventuality, creating a number of ring-shaped superweapons known as the Halo Array. However, the Didact was reluctant to use these and instead planned to use the Composer, a device capable of transferring organic consciousness to software, as a means to save the galaxy's populace from Flood infection. But the process was flawed, and those who underwent the process were unable to be reconstituted to their organic forms. This, however, suited the Didact's purposes: he would use the Composer to convert his Prometheans into mechanical warriors, later augmenting their numbers with converted humans to create a massive army to fight the Flood. In his view, this was both an elegant solution to the Flood problem and a means of neutralizing the human threat forever. However, his wife the Librarian was horrified by his actions, and sealed him inside the shield world Requiem, which was his base of operations. The converted Prometheans were left there to guard his Cryptum, and Requiem remained quiet for millennia after the Forerunners were wiped out by the Halo Array.

Contemporary situation
"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 the Sangheili species, it was not long after the end of the war that rogue splinter groups, many of them still hostile toward humanity, began to rise from among the remnants of the hegemony. With large amounts of former Covenant matériel at their disposal, it was inevitable that these disparate remnants would band together against their former enemy, against the best efforts of those who favored a policy of peaceful cooperation, an approach most visibly embodied by Arbiter Thel 'Vadam. Humanity'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.

The figure who would ultimately give a face for the new Covenant was a former Sangheili Shipmaster known as Jul 'Mdama. Although 'Mdama had always resented humanity (in particular their perceived virulent expansion and colonization) even in the wake of the human-Sangheili alliance, the ultimate catalyst for his quest against mankind came in the form of the death of his wife Raia, for which he blamed humanity due to their involvement in the Sangheili civil war. 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.

Sanghelios
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.

Draetheus V


In 2554, a 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 his comrade with her.

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 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. The events at the end of the battle also resulted in Dr. Catherine Halsey's apparent defection to Jul 'Mdama's Covenant, after ONI's failed attempt on her life.

Ealen IV


In March 2558, following an escalation in Jiralhanae raiding attacks along the Joint Occupation Zones, Ealen IV was chosen as a place for peace negotiations between the Sangheili and Jiralhanae. As Fleet Admiral Terrence Hood was meeting with Arbiter Thel 'Vadam and Jiralhanae Chieftain Lydus, they were attacked by Covenant mercenaries under the command of Shipmaster Vata 'Gajat and Champion Tek to stop the negotiations. 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. With their communications to their orbiting fleets having been blocked, the delegation were left without reinforcements.

Meanwhile, the peace between the Jiralhanae and Sangheili ships in orbit became worse, as they blamed each other for the lack of communication and were on the verge of attacking. Captain Lasky and Spartan Naiya Ray managed to disable the communications jammer on the surface, enabling them to alert the Jiralhanae and Sangheili fleets of the true culprits behind the attack. With his position exposed, Vata 'Gajat ordered a retreat. Back on the surface, the Spartans managed to evacuate the delegates, 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. They launched a freighter, the Pilgrims Pride which sent out a distress signal that was later picked up by Infinity. When Infinity arrived in the Artesia-702 system, it found the damaged freighter and tugged the ship into one of its deployment bays. An ambush was sprung within the bay when the freighter set itself to self-destruct and multiple UNSC aircraft exited its cargo bay. The attack was repelled by Fireteams Majestic, Colossus, and Fenrir.

After running an ID check on the Vultures and Sparrowhawks used in the ambush, the Infinity crew discovered that the assault crafts used were from the long-lost. With the Spirit's possible location found, Lord Hood authorized Palmer to conduct a search-and-rescue mission without being detected. Equipped with OF92 Booster Frames, Palmer and Fireteam Majestic scouted Oth Lodon's system. Exploring an asteroid field, the Spartans came across not the Spirit of Fire but instead an docked at a Covenant station.

After Infinity jumped to the vicinity of the station, Captain Clayton announced his vengeance against Admiral Hood and launched a surprise attack against Infinity with the station's powerful glassing cannon, completely disabling the ship. However, Commander Palmer and Fireteam Majestic were able to board the NCA station and seize the command center. They also destroyed 'Gajat's ship, which was preparing to attack Infinity, killing the mercenary leader.

A significant portion of the Infinity crew were killed in the attack, including Commander Bradley, while Fleet Admiral Hood was left paralyzed. Three days later, the UNSC dispatched a task force to repair Infinity and monitor the station. With Daniel Clayton captured, Hood visited the turncoat captain in his cell, querying Clayton about the intentions of the NCA's leader, Admiral Drake. Clayton only told Hood the NCA was stronger than before and had agents on every colony, even Earth, before being shipped to Midnight Facility on Hood's orders.

List of appearances

 * Halo: The Thursday War
 * Halo 4
 * Spartan Ops
 * Halo: Spartan Assault
 * Halo: Initiation
 * Halo: Escalation
 * Halo: Mortal Dictata
 * Halo: Spartan Strike