Outbreak on Installation 00

"I'll look around. And if we find prizes to bring it back, how could that go wrong?"

- Voridus

The Outbreak on Installation 00 was a large-scale outbreak of the Flood on the Ark in 2559.

Prelude
At the end of the Human-Covenant War, Covenant and Human forces clashed at Installation 05, discovering the large-scale outbreak of the Flood there. The Flood would eventually take over the and use it to transport the parasite aboard High Charity, the holy city of the Covenant. The Fall of High Charity followed in the onset of the Great Schism, resulting in the Flood taking control of the titanic space station and the billions of residents therein.

In December of 2552, the UNSC and last remnants of the loyalist Covenant found their way to the extragalactic megastructure known as Installation 00. During the ensuing fighting, the Gravemind would use its knowledge to transport High Charity to the installation, with the hulk of the city crashing on the surface and peppering the surrounding landscape with debris and Flood forms. Spartan John-117 and Arbiter Thel 'Vadam would travel to the city to extract the AI Cortana from the Gravemind's clutches, in the process destroying some of the still-operational power reactors in the city. The three would escape the city as it exploded beneath them, believing the Flood threat to be finished.

Following the faulty firing and destruction of Installation 08 and the damage it dealt to the Ark, the vast majority of the Flood were destroyed. Because Installation 08 was incomplete and falling apart, a few Flood survived the faulty firing. The installation's monitor, 000 Tragic Solitude, began to construct a sterilized quarantine zone around the wreckage of High Charity, ensuring that no life could survive around the site that the Flood may potentially use for sustenance. For seven years, the few surviving Flood inside the rubble of High Charity festered, until the arrival of the and the Second Ark Conflict in 2559 provided them with a food source.

UNSC scouting
High Charity's remains would remain largely untouched in the conflict, though by June 1, the vessel had sent out recon teams to investigate the site. One such team led by G. Peterson reported a 300-meter boundary by which all flora and fauna stopped growing and an unparalleled swarm of Sentinels patrolling this perimeter. Peterson and their squad were ordered by Captain James Cutter to keep watch of the site for Banished activity, following a close shave with a Forerunner months prior.

Banished scavenging
On June 4, 2559, Atriox summoned warlords Pavium and Voridus for a new mission. As Captain Cutter had predicted, he was interested in scouting out the ruins of High Charity, and tasked the two brothers with investigating the region surrounding the quarantine site. The goal of the mission was to simply investigate the region surrounding High Charity for formerly-Covenant supplies and weapons, ever crucial especially with the loss of Enduring Conviction some months prior. Atriox was clear; under no circumstances were attempts to breach quarantine and enter High Charity to be made due to the danger of the Flood still being present inside.

The Banished set up a camp near the crash site, with Plipbab acting as the Unggoy coordinator for the base. In this time, Voridus experimented with Mgalekgolo incendiary gel, the experiments inadvertently killing several grunts in the process. Several groups of Banished personnel would begin to investigate the wreckage of old Covenant spacecraft surrounding the site. The Banished's Banshees began engaging the Sentinels around the area, as Jiralhanae-led grunt squads began to converge on the site. The teams soon found their way obstructed by debris, however, leading to Locusts being deployed to help cut through the debris. Reavers would later be deployed to help deal with the increasing Sentinel presence. Despite the quarantine zone around them, many of the Banished infantry - including Voridus himself - did not believe that the Flood threat really existed, and that instead the fall of High Charity was simply a Covenant lie.

As the scout teams converged on the Banished base, they found it under attack by Sentinels. The Banished responded by firing a Disruption emitter at the Sentinel launching bay, temporarily preventing it from deploying more aggressors. Eventually, the Banished were able to deploy Voridus' modified Scarab, intended to begin cutting through the heavy debris lining the region. The Banished concentrated their forces on defending the Scarab as it worked its way forward, eventually coming across the UNSC scouting party and two minibases. The Banished destroyed the human presence and pushed forward, encountering more and more Sentinel resistance including Forerunner turrets and eventually two Retriever Sentinels. As the two automatons bore down on the Scarab, Voridus was able to deactivate the Sentinel control network, destroying the Sentinel defenses in the region for good. Pavium reminded Voridus of their orders to leave the quarantine intact, but Voridus ordered the Scarab to break the shell anyway, insistent that he could handle himself.



Awakening a nightmare
The Scarab successfully blasted a hole in the quarantine shell, allowing the brutes to enter the ruins of High Charity freely. Voridus ordered a small pack of Brutes to enter the structure and report what they found. The group entered noisily, and were quickly beset upon by the Flood. Eventually, one brute would make his way back to the surface, only to reveal himself a combat form turned by the Flood. The lone infected was quickly followed by a tidal wave of pod infectors and Abominations, who quickly surrounded the small Banished party and began to overrun them, as thousands more Flood escaped into the surrounding landscape of the Ark. Voridus would retreat into a Forerunner structure, and begin to hold off the Flood there while surrounded.

Voridus and his surviving troops fell back and tried to make contact with Pavium to warn him of the threat, but were unable to do so, despite several of Pavium's Huragok attempting to patch the communications. Pavium and his group noticed movement inside the wreckage of High Charity, and were set upon by a horde of infection forms, with Pavium ordering them to kill those who were infected. Pavium and his forces fell into a pattern of defending as long as they could, before falling back to a new safe zone once one area was overrun. Pavium was able to request reinforcements from Colony, who was able to deploy two Goliaths to help assist in clearing wreckage blocking the path of the retreating Banished troops. Eventually, the Flood were able to infect vehicles, and began sending the infected vehicles at Pavium's forces, followed by the burrowing Flood bursters.

Eventually, Pavium and his forces were able to retreat to a nearby Banished outpost, which was already under siege by the Flood. The group were able to use some nearby abandoned Gydrozka Workshop Blisterbacks to help in the defence of the region, while the Flood began to pour more and more forms into the region, eventually beginning to burst roots from underground behind the defensive lines. This defense would not last long before the group had to retreat yet again. They began making their way to meet up with Voridus, but found their way blocked by a gargantuan Flood tentacle, forcing them onto a different path. The group continued to be pursued until they eventually found their way to an Eklon'Dal Workshop Antlion, which they were able to use to hold off the Flood in pursuit.

The Flood would also begin to assault another outpost commanded by Plutus. The base's brute guards initially laughed at the warnings given by several grunts, before being set upon by the Flood themselves, a horde overrunning a Wraith tank. Plutus ordered his troops inside, but the Flood were easily able to enter the base through cracks and vents, and the outpost became a slaughterhouse. Plutus planted several plasma mines and retreated into an inner corridor, where he barricaded the door. He was able to send a last message to Voridus before he was overrun.

Lighting the fuse
Voridus' base did not hold for long, and they soon found themselves attempting to retreat and meet up with Pavium's forces. Their way would once again be blocked, before both commanders decided to restart the salvage operations they had been running earlier. The region they were in ran with unstable chemicals and energies, which could potentially be leveraged by the salvage drills if the Flood could be held off for just a short while. Pavium's forces set up a defense near the drill site, and began defending their base while they generated enough power to keep the salvage drills online. The Flood had established several hives around the site, and the regular pressure increases forced the pustules to regularly discharge new Flood forms including Seeder infectors and infesters into the environment, which began to attack the operation. However, the Banished were able to hold out long enough to discharge the drills and light the chemicals under the ground, destroying the Flood threat in the immediate area and buying the Banished forces time to breathe. Pavium ordered Voridus to send a party down into the Archive, believed to be connected to the Sentinel defense network he had deactivated earlier, while the rest of the troops stayed above ground to hold off the Flood.



Reactivating the Sentinels
Voridus and his party - consisting of Sangheili Rangers and Jiralhanae Jumpers - descended a lift into the Archive, intending on re-activating the Sentinel network. The facility's defensive systems were still active, with damaging lasers and many chasms requiring use the jump pack systems brought by the brutes. The party soon encountered a Flood spawner form and hundreds of pod infectors, signifying the Flood had already managed to infest the structure. Voridus was able to make use of the automated defenses to lead the Flood into traps, and made use of his Infusion gel to quickly take down more Flood forms. Voridus eventually managed to reach a teleporter, which he was able to use to bring in more reinforcements, including an Honor Guardsman. The guard was equipped with active camouflage, which he was able to use to bypass some Flood and reactivate a minor defensive system. The group eventually encountered a deactivated light bridge, which the jump brutes were able to cross and reach the control panel. The troops were once again beset upon by the Flood while waiting for the bridge to activate, before once again using the Honor Guard to sneak past some Flood and activate more defenses. The Banished eventually managed to activate a quarantine protocol with one problem - the quarantine would kill them along with the Flood, unless they were able to eradicate the Flood in the area within two minutes.

The Banished would narrowly manage to avoid being caught in the quarantine measures, and begin making their way to the final control room. They encountered increasing resistance by both the Forerunner defenses and the Flood, who had begun sending Abominations at the group. They were successful in reaching the control mechanisms, which they realised had been infested by the Flood already, as if the parasite knew of the importance of the mechanism. Flood growth blocked the mechanism from working, requiring the Banished troops to begin clearing out the Flood and resetting the system. After defending for several minutes, the Sentinel network was successfully brought back online. However, another Banished outpost reported in that they were being overrun by a massive Flood form. Thankfully, Pavium was also able to report that Atriox was sending reinforcements.

Destroying the Flood
Now back in contact with Atriox, Pavium and Voridus were able to begin planning how to finally defeat the Flood. Atriox was pulling troops back from many of his bases, and heading to the site to personally deal with the situation, warning the brothers to have the situation fixed by the time he arrived. Pavium and Voridus arrived via Spirit dropship to survey the scene and begin coordinating the defense of another outpost. Once the Flood was fought off, the group began scouting the area around them, only to find their way blocked by more of the massive tentacles from earlier. Pavium deployed a Antlion to fire on the tentacle, making it retreat and allowing the group to proceed and eventually find the source of the chaos; a gargantuan Proto-Gravemind, beginning to mature into a fully-fledged Gravemind.

The Proto-Gravemind was defended by a heavily armoured carapace too thick for conventional weaponry, requiring the Antlions to begin concentrating fire on the creature while the Banished army fought to secure more turret deployment sites and defend those constructed. Eventually, the combined might of the Banished forces, artilery and orbital bombardment was able to finally kill the Proto-Gravemind and put a temporary halt to the Flood outbreak, as Sentinels began to pour into the region to contain the threat. Following the destruction of the Proto-Gravemind, Atriox arrived in a Eklon'Dal Workshop Lich to reprimand the brothers and take control of the situation. He ordered the two warlords to secure the breach and clean up the mess, and that he would await them once done. The Banished and Sentinels then worked together to contain the Flood and seal off High Charity once more. Ultimately, the Banished and the Sentinels succeeded in "scouring" the Flood from High Charity.



Aftermath
Although the Banished were able to stop the Flood infestation, it cost them heavily. Hundreds of troops and vehicles in the region - 40% of Pavium's forces - were outright destroyed or consumed by the Flood, with bases completely overrun. Eventually, Atriox was forced to abandon positions he'd spent months fortifying against the human campaign on the installation, realizing the need to pit every single soldier he had against the Flood threat.

Following the defeat of the Flood and the parasite being scoured from High Charity, the Banished were able to pillage the city's data stores and retrieve, amongst other things, a Forerunner entanglement dish and the access code to Anodyne Spirit. The former was ultimately able to be used by Atriox to send a brief message to Escharum; commanding him to rally the Banished at Reach and begin to dig up the portal complex on the planet. Meanwhile, a task force under Chieftain Minas was organized to conduct a Banished raid on the grounded keyship, intent on linking the forces of the Banished with their reinforcements back in the Milky Way.

Ground forces

 * Clan of the Long Shields

List of appearances

 * Halo Wars 2
 * Halo Wars 2: Awakening the Nightmare
 * Halo: Shadows of Reach
 * Sacrifice
 * Halo: Divine Wind
 * Halo: Outcasts