Reformation

"The Reformation is but a new beginning. The Auditorium will spill its secrets. The Endless will walk this world once more."

- The Harbinger, speaking to John-117

Reformation is the process by which a Halo Ring repairs itself.

Background
Whenever a Halo Ring suffers damage, its Sentinels (assuming there are any left) almost immediately begin to assess the damage and initiate repairs. However, depending on the severity of the damage, this natural repair process can potentially take millions of years to complete. The Reformation is meant to greatly accelerate the Ring's restoration. During the Reformation, multiple Reformation Spires emerge from the surface of the Ring. Once fully activated, the Spires create raw materials which are then sent out to repair the Ring. The Spires are controlled by a Command Spire, which operates in conjunction with a facility directly below called the Nexus.

History
On at least one occasion prior to the Battle for Zeta Halo, Zeta Halo suffered damage serious enough to warrant the Reformation. Despondent Pyre, the Ring's Monitor, subsequently summoned the Reformation Spires needed to repair the installation and ensure the Xalanyn remained imprisoned. The Monitor later noted that the installation's ability to deploy its Reformation Spires at her request was one of the things that made this Ring different than the others.

During the Battle for Zeta Halo, the Banished and the Harbinger sought to utilize the Reformation to restore the Silent Auditorium, which had been destroyed when Cortana sacrificed herself to stop Atriox from gaining control of Zeta Halo. Secretly, the Harbinger intended to use the Reformation to not only restore the Silent Auditorium, but to remake the Ring itself for her own purposes.

On May 28, 2560, the Harbinger kidnapped Despondent Pyre and extracted her encephalon. Using the Forerunner routines contained within Despondent Pyre's encephalon, the Harbinger constructed a protocol which she used to summon dozens of Reformation Spires. The Spires still required an initialization sequence to become fully activated, so the Harbinger traveled to the Command Spire to personally initiate the Reformation.

At the same time, Master Chief John-117 and his AI companion, The Weapon, headed to the Reformation Spire nearest to the Conservatory, where they had first encountered the Harbinger. After defeating the Banished forces surrounding the Spire, the Chief entered the structure through its gravity lift. Once inside, he and the Weapon were greeted by Zeta Halo's Sub-Monitor, Adjutant Resolution, who led them to the Spire's Observation Platform. When the Chief learned about the Spire's purpose, the Spartan-II ordered the Weapon to shut it down. In response, Adjutant Resolution deemed the pair a threat to the Reformation and attacked them. After the Chief defeated Adjutant Resolution, the Weapon discovered that multiple Spires were being deployed. She also discovered that the Spires were resisting the Harbinger's efforts to activate them because the protocol used to summon them was only partially correct. The Weapon managed to remove the Spire she and the Chief were standing on from the network, as well as trace the source of the activation attempts to the Command Spire. However, this action not only caused the Spire's Observation Platform to start disassembling itself, forcing the Master Chief to call Echo 216 for emergency extraction, it also alerted the Harbinger to the Weapon's existence.

After the Spartan Killers Hyperius and Tovarus failed to kill the Master Chief, the Harbinger instructed Escharum to have his forces protect the Command Spire while the Reformation was underway. She also sought to learn more about the Spartan's ally.

When the Chief and the Weapon arrived at the Command Spire, they discovered that the Harbinger had altered the Forerunner sequence needed to open the door at its base, making entry impossible. The sabotage forced the Chief and the Weapon to reconstruct a pure version of the sequence by gathering data from a network of nearby Forerunner communication beacons. During this time, the Harbinger spied on the Weapon and determined she could utilize the UNSC AI's routines in conjunction with those from Despondent Pyre's encephalon to break through the Spire network's resistance. While collecting data from the beacons, the Weapon eventually detected the Harbinger's presence within the beacon network and realized the latter's intentions. Since the Spires still hadn't been activated yet, the Master Chief initially wanted to abort their current plan, effectively leaving them and the Harbinger in a stalemate. However, the Weapon believed that the Harbinger would eventually find a way to activate the Spires on her own, so they had no choice but to finish gathering the data needed to enter the Command Spire.

After reconstructing the Forerunner sequence and opening the door, the Weapon determined that to get into the Command Spire itself, they would first have to descend into the Nexus, a facility directly below, and access its gravity lift. The Chief fought his way through Banished and Sentinels and reached the Nexus's central chamber. After the Chief restored power to the gravity lift, the Weapon accessed the Nexus's systems in order to activate the lift. The Harbinger then sprung her trap and hacked the Weapon, intent on using her to start the Reformation. The Weapon, in turn, used her link to the Harbinger to try to steal Despondent Pyre's encephalon. Despite the Master Chief's attempt to delete the Weapon - an effort which the Weapon herself stopped - both the Harbinger and the Weapon succeeded in their respective goals. This caused friction between the Chief and the Weapon, with the Chief being angry that the Weapon had stopped him from deleting her and had thus allowed the Reformation to begin, while the Weapon - who believed the Harbinger would have found a way to start the Reformation regardless - was angry that the Chief had tried to delete her in the first place rather than trust her.

With the Reformation underway, the Spires began forging building blocks which were sent out to repair the Silent Auditorium. Upon entering the Command Spire, the Master Chief battled numerous Banished troops, Skimmers, and Aggressor Sentinels as he made his way to the top, eventually reaching the main elevator that would take him to the Spire's Observation Platform. There, he encountered Adjutant Resolution who had survived their initial confrontation. The Sub-Monitor, now equipped with an improved combat chassis, tried to stop the Spartan, but the Chief defeated him again. The Chief then took the elevator to the Observation Platform, where he fought and defeated a trio of Banished Phantoms. He then deployed the Weapon, who used Despondent Pyre's encephalon to shut down all the Spires and end the Reformation, though not before the Silent Auditorium had been partially rebuilt.

Despite the loss of the Spire network, the Harbinger and her allies continued to rebuild the Auditorium. By the time the Chief arrived at the Auditorium, enough of the facility had been restored such that the Harbinger could use it to locate and free her people. Ultimately, the Chief defeated her before she could unleash the Endless. Before dying, the Harbinger sent a message to an unseen ally, informing them they had what they needed to complete her work. Shortly after her death, Atriox entered the containment facility where the Endless were imprisoned.

List of appearances

 * Halo Infinite