Battle of Meridian (2558)

In October 2558 a battle took place on Meridian, fought between the forces of the United Nations Space Command, the Liang-Dortmund Corporation (LDC) and the Created.

Background
In the fall of 2558, Cortana began to reawaken the Forerunner's fleet of peacekeeping Guardian Custode from across the galaxy and bring them to her location on the world of Genesis. The first five she activated within 72 hours of each other from human colony worlds, although she was unable to control which Guardians awoke and where. However, with the aid of the Warden Eternal, Cortana managed to control the release of one Guardian; located on the glassed moon of Meridian. She then used the Domain to instruct SPARTAN-117 to come to Meridian.

Blue Team's decision to go AWOL in pursuit of Cortana attracted the attention of Fireteam Osiris, a group of SPARTAN-IV super soldiers who were then tasked with locating and returning them to the UNSC.

First Promethean assault
On October 25, 2558, the first Prometheans appeared on the surface of Meridian and immediately began attacking the miners of the Liang-Dortmund Corporation. The LDC was largely unprepared and stood little chance against the sudden and overwhelmingly aggressive constructs. The meager air forces and anti-air batteries which the LDC could muster were swiftly destroyed by the Prometheans' Phaetons, and all evacuation attempts were discontinued when the moon's only space elevator, Pinnacle Station, was surrounded by Promethean infantry.

Shortly after the start of the attack, Fireteam Osiris arrived above the moon and began a descent on the space elevator, not realizing that the mining colony was under attack. As the SPARTANs were approaching the surface, they were hailed by Governor Sloan, who demanded to know what the UNSC was doing at the old colony. Realizing that the Liang-Dortmund Corporation had made violent contact with Promethean forces, SPARTAN Locke pledged to aid the LDC in exchange for assistance in locating Blue Team. After making landfall, Fireteam Osiris broke the siege of Pinnacle Station and pushed towards Meridian Station, where the brunt of the Promethean attack was centered.

With Pinnacle Station secured, Fireteam Osiris commandeered several vehicles from the station garage and began to remove the Promethean presence on the surface, rescuing several surrounded teams of LDC miners in the process. Although the LDC continued to deploy aircraft in an attempt to forestall Forerunner airstrikes, the superior technology of the Promethean Phaetons meant that Osiris and the LDC forces were forced to fight through increasingly thick resistance in order to reach Meridian Station. Utilizing the considerable arsenal that the anti-centralist Governor Sloan had amassed, the humans were eventually able to clear the approach to Meridian Station of all Promethean forces. Sloan begrudgingly thanked the SPARTANs for their assistance in protecting his people and instructed the miners still at Meridian Station to cooperate with Osiris.

Hunting Blue Team
The SPARTANs eventually gleaned from the LDC personnel that a ONI prowler had been seen docking on the airpad at Apogee Station. Leveraging the modicum of Sloan's trust that they had earned, Osiris secured transport to Apogee Station on board one of the corporation's dropships, supported by a team of miners detailed by the governor to "keep an eye" on the SPARTANs' activities.

Once at Apogee Station, the SPARTANs and LDC miners found an incredibly thick concentration of Promethean forces had overrun the station. Fighting up the station's primary landing pad, the humans eventual reached a moored. After clearing the Prometheans from the area, Osiris used the state-of-the-art Artemis Tracking System to scan the prowler, confirming that Blue Team had disembarked the vessel shortly before and made their way towards a subterranean excavation further within Apogee. After securing the entrance of the excavation, Governor Sloan opened the blast doors to allow Osiris within while simultaneously pulling the LDC miners back to Meridian Station.

As Fireteam Osiris delved deeper and deeper within the LDC excavation, they discovered that the corporation had discovered a massive Forerunner structure housed in a volcanic cavern far below the surface and utterly untouched by the Covenant glassing ten years earlier. Here the SPARTANs encountered the Warden Eternal, a Promethean construct tasked with safeguarding the Guardian Custode interred at the heart of the cavern. The Warden Eternal informed them that Blue Team had been permitted access to the Guardian, but that Osiris's presence was considered trespassing. Determined to catch the SPARTAN-IIs before they reached the Guardian, Fireteam Osiris engaged the Warden in combat, defeating him after a prolonged battle. As seismic activity began to increase, Osiris advanced to the final chamber of the Forerunner structure.

The last chamber lay in the lowest depths of the volcanic cavern, and it was here that Fireteam Osiris found the Guardian and Blue Team. Using a complex set of tiered teleporters, the two SPARTAN teams raced each other to the Guardian. The Master Chief and SPARTAN Locke arrived nearly simultaneously at the final teleporter. Locke instructed the SPARTAN-II at gunpoint to stand down with the rest of his team and return with Osiris to. However, at the Master Chief's command the rest of Blue Team disappeared into the final teleporter and boarded the Guardian. When Locke insisted that John-117 allow Fireteam Osiris to pursue Cortana instead of Blue Team, the Chief attacked Locke; attempting to incapacitate the SPARTAN-IV while avoiding his primed armor restraining device. Locke succeeded in dealing the SPARTAN-II a hard enough blow to damage his armor, but the fight ended shortly thereafter when the Master Chief managed to paralyze Locke with the active armor restraint device. The Chief then followed the rest of Blue Team into the teleporter, which closed as the seismic activity in the cavern intensified.

The rest of Fireteam Osiris arrived at Locke's position shortly after the Master Chief's departure and freed the SPARTAN of the armor restraint. But the team soon realized that Guardian had been activated and that the seismic activity they had encountered was the massive Forerunner construct preparing to breach the surface. As the entire cavern began to collapse, Osiris hurried back down the teleporters towards the front of the cavern.

Prometheans return
The final teleporter brought them back to Meridian Station, where they found a full-scale evacuation in-effect, despite the ongoing threat of Promethean Phaetons. Knowing that the air was too dangerous to commandeer a LDC Pelican, Osiris raced back towards Pinnacle Station in the hopes of riding the space elevator back into orbit. As they retraced their steps back to the station, the Guardian burst from the vitrified crust of the surface, showering the battlefield in magma from the subterranean cavern and triggering another wave of earthquakes. Several evacuation shuttles were shot down as the Prometheans redoubled their assaults on the colony. Osiris arrived at Pinnacle to find that the elevator was once again surrounded by Promethean forces. After destroying the occupying constructs, Osiris entered the station and re-powered the elevator.

With Pinnacle Station secured and power restored to the space elevator gondola, Fireteam Osiris and the last of the Liang-Dortmund Corporation colonists began their ascent. The humans were attacked incessantly by Prometheans warping into the moving gondola, and all the while the Guardian slowly began powering its drives for a slipspace jump. As part of its pre-jump power sequence, the Guardian emitted a series of destructive kinetic pulses as a self-defense precaution. Due to the Guardian's close proximity to Pinnacle Station, the first of these pulses crippled the elevator's maglev suspension system; immobilizing the gondola high above the surface of Meridian. The sudden stop killed all of the LDC personnel and stranded the SPARTANs several hundred feet shy of the landing pad where their Pelican was docked. Using the maintenance hatches, Osiris gained access to the exterior scaffolding of the elevator, climbing up the last levels while fighting teleporting Prometheans and evading Phaeton fire. As the Guardian's pulses increased in frequency and intensity, Osiris reached the Pelican and escaped the collapsing scaffolding just as the Forerunner construct entered slipspace.

Blue Team and Fireteam Osiris
Blue Team's Guardian would eventually arrive on Genesis, a Forerunner Builder planet in the Nomos system, where they would discover other Guardians, meet the Warden Eternal, and learn of Cortana's survival and her plan for the enforcement of the Mantle on the galaxy.

In parallel, Fireteam Osiris would retreat back to Infinity. Roland analyzed data acquired from Meridian's Guardian, and Captain Lasky and Dr Halsey devised a plan to use another Guardian, on Sanghelios, to join up with Blue Team. They would thus meet up with the Arbiter and the Swords of Sanghelios.

Activities on Meridian
After the Guardian was taken to Genesis, all the Promethean forces disappeared along with it. On October 28, four survivors of the Guardian's departure from Meridian constructed a transmitter in an attempt to get off Meridian. They intercepted Cortana's speech to the Galaxy from the day before, only wanting to leave the planet, the survivors sent a message back and asked for help. Soon after they got a response that everything would be dealt with in time. Despite the loss of the orbital elevator and of its local headquarters, Liang-Dortmung still received important demand for Meridian's vitrified resources. They relocated their efforts to Darkstar Station, a remote polar outpost. Its workers and engineers had remained mostly unaware of the catastrophe that had happened on the other surface of the planet-moon. The company sent additional ships and personnel to accelerate resource gathering as long as possible, profiting from a tacit permission from the UNSC, and the lack of risky Created activity in the system. Still, the UNSC would prepare a return to Meridian in order to investigate ancient machinery dormant under the surface.

List of appearances

 * Hunt the Truth
 * A Hero Falls
 * The Hunt Begins
 * Halo 5: Guardians
 * Halo Mythos
 * Halo Fractures
 * What Remains
 * Rossbach's World