Battle of Installation 00

"Our fight is through the Portal, with the Brutes and the bastard Truth!"

- Shipmaster Rtas 'Vadum

The Battle of Installation 00, also known as the Ark Conflict, was a large battle between the UNSC-Fleet of Retribution alliance, the Covenant, the Flood, and Forerunner Sentinels on December 11, 2552. It was the final battle of the Human-Covenant War and was the last stand of the Covenant, making it one of the few major engagements in the entire war in which the Covenant were on the defensive.

Battle of Installation 04
During the Battle of Installation 04, Cortana intercepted the Installation's Index as it was being inserted by Spartan-117. She continued to hold on to it after she had been removed from the Installation's Control Room. She also had spent over twelve hours inside the Control Room's computer, gaining an incredible amount of information about the Halo installations, making her possibly the most knowledgeable regarding the operation of the Halo rings, the Forerunners and the Ark perhaps even more so than 343 Guilty Spark who admitted he was quite ignorant of the Forerunner structures beyond Installation 04.

Battle of Installation 05
The Battle of Installation 05 included many events that would become major factors in the Battle of Installation 00.

The UNSC AI, Cortana, remained aboard the Covenant holy city, High Charity as the Flood and its central consciousness, the Gravemind, took control of it. From there, the Gravemind interrogated her, and she willingly answered its questions.

The aborted activation of Installation 05 had set all of the Halo rings to standby, where they could be activated from the central location of the Ark.

Finally, the Covenant civil war, termed the Great Schism, and the human-Sangheili alliance began in the space around Installation 05.

Battle of Earth
The High Prophet of Truth had arrived on Earth with the rest of his fleet, to complete the digging of a Forerunner structure under the planet surface. Eventually they uncovered and activated it, opening a slipspace portal that would take them to the Ark, a Forerunner structure from which Truth can fire all of the Halo installations at once. As he departed through the Portal, a Flood-captured ship arrived on Earth and crashed. From it, John and the Arbiter were able to extract a message from Cortana, alerting them that High Charity was heading for Earth and indicating that the solution to the problem of the Flood lay beyond the portal.

While Lord Hood was suspicious of Cortana's warning and objected to going through the portal, Commander Miranda Keyes, Spartan-117 and Ship Master Rtas 'Vadum all indicated their wish to proceed through the Portal. Lord Hood gave Miranda Keyes command of the Forward Unto Dawn for the human commitment to the mission and the fleet of ships chased after the High Prophet of Truth.

Battle
"Sangheili Major"

- Rtas 'Vadum

The High Prophet of Truth, having successfully activated the artifact in Voi, left Earth through a slipspace portal to the Ark, a Forerunner structure that can be used to fire all of the Halo installations at once. Despite Lord Hood's skepticism, Commander Keyes took the Forward Unto Dawn with a small fleet of Sangheili cruisers led by the assault carrier Shadow of Intent and proceeded through the Slipspace portal, arriving at the Ark. The Sangheili immediately engaged the Jiralhanae fleet stationed to protect the Prophet while the Dawn deployed the Master Chief and Orbital Drop Shock Troopers in six D77H-TCI Pelicans to locate Truth. Despite being outnumbered three-to-one in space, the Sangheili fleet made short work of the Covenant space forces due to the Jiralhanae being outmatched by the Sangheili in their knowledge of naval warfare. The Covenant fleet had been destroyed and the only ones left alive were Truth and his forces on the Ark. Also, presumably Truth landed the Forerunner Dreadnought on the Ark although it was never seen again and was specifically said not to take part in the battle above the Ark.



Operation: BLIND FAITH
As part of an operation called Operation: BLIND FAITH, five of the Pelicans deployed by the human frigate Forward Unto Dawn had made it to the Ark. The Master Chief and four ODSTs were deployed, ambushing a group of Brutes, Grunts, and Jackals listening to a message from Truth. They then proceeded to ambush another group of Covenant loyalists building an Anti-Aircraft Gun. They entered a small cave, where the Chief first accessed the Forerunner Terminal network. On the other side of the cave they met a pair of Marine survivors from a second shot down Pelican and witnessed a GA-TL1 Longsword fighter crashing. After being informed of a possible landing zone for the Forward Unto Dawn, the humans ambushed the Brutes and Grunts searching the crashed Pelican, then destroyed a pair of Type-52 Prowlers that attacked. Now with M274 Mongoosees, they continued past the crashed Longsword, a pair of HEVs that had landed and had the ODSTs which had once occupied them killed once they left their pods, and a crashed Type-52 Phantom to a battle between Covenant and Sentinels outside a Forerunner barrier. Avery Johnson informed that he had spotted a structure that was similar to the Cartographer of Installation 04 on the other side of the wall, and Keyes set it as their objective. The Dawn would need to land first however. After meeting another group of Marines being attacked, the vehicles led by the Chief then moved to the sighted Landing Zone, which was occupied by a pair of Anti-Air Wraiths. After they cleared the LZ, the Dawn disengaged from the space battle and dived onto the surface of the installation, landing safely.



From the Dawn's hangar, the Master Chief, ODSTs, and Marines were reinforced with three M808C Scorpions tanks and an M12 Warthog LRV. The human force then fought their way through a large reinforcements force back to the Forerunner wall. The Chief went through the upper, smaller doorway while the armor and vehicles (reinforced with one more Warthog and an M12G1 Gauss Warthog) went through the larger, lower doorway. After activating a light bridge the Spartan went through the wall, only to see a Type-47 Scarab and a Covenant armored force destroy the Warthogs. He then fought his way to the lower doorway, which then finally opened fully, letting the tanks through. Sergeant Stacker and the Chief led the Scorpions and a Warthog through two Covenant defense lines of Type-25 Choppers, Type-32 Ghosts, Type-26 Wraiths, and infantry with heavy weapons, reinforced by a Phantom. When the Scarab returned, the humans then proceeded to destroy it, plus the Choppers and infantry reinforcing it. By now the Elites had defeated the entirety of Truth's remaining fleet. The Shadow of Intent landed near the Cartographer.



343 Guilty Spark, now working with the UNSC-Sangheili alliance, led Spartan-117 and the Arbiter Thel 'Vadam, plus a pair of Marines, to the Ark's Cartographer. Fighting their way through several incompetent and unprepared forces that were asleep, they get back outside where they pinpointed the Prophet's location. By then Truth had already holed himself in a secure facility in the core of the Ark and had activated a large barrier around the entire core to ward off the attacking forces. After discovering Truth's location, the UNSC-Sangheili troops were attacked by a large Covenant air force. Johnson led the air battle against them, and 'Vadam stole a Type-26C Banshee to help him. The Chief, with the pair of Marines, fought his way past a group of Stalker Brutes. He then dueled with Jiralhanae Chieftain Cethegus and defeated a squad of Jump Pack Brutes before being picked up by Pelican Kilo 023 after the Covenant air force was dealt with. The humans and Elites set forth to attack Truth to stop him from activating the rings.

Battle of the Citadel


The UNSC ground forces, carried in five Pelicans, along with Sangheili reinforcements in a pair of green Phantoms, assaulted three emitter pylons that powered a small section of the barrier. The Master Chief and a small squad of three of ODSTs were deployed a distance from the first tower by a Pelican after hostile fire shot down a second Pelican carrying Marines and a Warthog. The crashing Pelican also took out the ODSTs' Warthog. Thel 'Vadam and Elites assaulted the second tower. Sergeant Johnson took four Marines and attacked the final tower. Clearing the Covenant loyalist heavy weapons on the beach, a new Warthog and a Mongoose were deployed and taken through heavy resistance to the tower. Clearing it, the Chief learned that the Sangheili had taken down the second tower, but Johnson had been ambushed by enemy reinforcements. The Chief returned to the beach, commandeered an AV-14 Hornet and helped destroy Covenant Banshees and a Phantom, securing air control for the UNSC-Sangheili forces outside the barrier. Destroying the Brute defenders outside the third tower with Hornets and Pelicans, Master Chief, Thel 'Vadam, and a team of five Elites discovered the corpses of the Marine team, except for Johnson's. When the defending forces were eliminated and the barrier deactivated, the Shadow of Intent prepared to bombard the Citadel, but was prevented from doing so by the arrival of the Flood-infested High Charity, which launched debris that crippled the Sangheili carrier and spread Flood across the Ark. Keyes insisted that this would only pressure Truth into activating the rings, and ordered the remaining forces to attack him directly.

Fighting through a group of Flood, the Elites and the Chief met up with Sergeant Stacker's Marines, supported by a Scorpion, a Gauss Warthog, and a Mongoose. The humans and Elites fought through the cliffs to the area outside the Citadel, the structure which could remotely activate all of the Halo Array. The Covenant attempted to reinforce their troops by a large amount of Phantom transports gathered from around the installation, but the UNSC air forces countered this by attacking the Phantoms and their Banshee escorts with Hornets and Pelican Gunships. The ground forces managed to destroy the remaining Covenant armor on the mountainside. Given another Gauss Warthog and air support from a flight of Hornets and a Pelican, the Marines destroyed Banshees, Ghosts, a Prowler, plus a pair of Scarabs dropped in front of the Citadel by Brutes. After the destruction of the Scarabs, the Covenant had lost their grip on the Citadel area. Without any heavy support, Spartan-117 and 'Vadam personally attacked the facility where Truth was to activate the Halo installations.



Sergeant Major Johnson, who had disappeared during the assault, was in fact captured by Truth's forces and was being tortured into pressing the final switch to activate the other Halos. With Spartan-117 and the Arbiter too far away to stop High Prophet of Truth, Commander Keyes grabbed a Pelican dropship and crashed into the facility to rescue Johnson, but was killed soon after by Truth himself. However, her actions delayed Truth long enough for Spartan-117 and the Arbiter to stop him. The Gravemind dispatched Flood forces to assist Spartan-117 and the Arbiter in preventing the Halos' activation and the Arbiter personally killed Truth. However, the Gravemind betrayed them soon after and while Johnson managed to escape with Commander Keyes' body in the Pelican, Spartan-117 and the Arbiter had to fight their way outside with the assistance of some Sentinels.

After making their way outside, the group discovered Installation 08. 343 Guilty Spark explaining that a tactical pulse from it would eliminate the Flood infestation. However, this new Halo lacked an Activation Index. The only way they could get another Index was to rescue Cortana from High Charity since she still possessed the Index from the original Installation 04.

Johnson picked up the Arbiter and the Chief while Guilty Spark went off to the new Installation. The party then headed to the Shadow of Intent, where Johnson, 'Vadam, and Ship Master 'Vadum rounded up the UNSC and Sangheili forces. Meanwhile, Master Chief infiltrated High Charity, successfully recovering Cortana and the Index and sabotaging the city's reactors. He escaped with the help of 'Vadam and fled onboard a crashed Pelican as the station exploded, ostensibly destroying the Gravemind.

Finishing the fight
"Rtas 'Vadum"

- Thel 'Vadam

With the Index secure, Thel 'Vadam ordered Rtas 'Vadum (who had safely evacuated humans and Sangheili back onboard the Shadow of Intent) to escape back through the slipspace portal to Earth while he, Spartan-117, and Sergeant Major Johnson moved in on the Control Room of the incomplete Halo. The Dawn was left behind for them to use to escape. The Gravemind, meanwhile, had begun to rebuild itself on the new ring, and sent Flood dispersal pods to kill the three interlopers. The Chief, 'Vadum, and Johnson, with the assistance of local Sentinels and 343 Guilty Spark, fought through the Flood and entered the Control Room. Spark explained that the new Halo would be ready to fire within days, to which the group, particularly Johnson, protested. When Guilty Spark informed the three that activating Halo now would destroy both the Ark and the installation, Johnson told him to "deal with it" and prepared to activate the ring.

"Send me out...with a bang."

- Johnson's last words

Unwilling to let "his" ring be destroyed again, 343 Guilty Spark went rampant, mortally wounded Johnson, took down Spartan-117's shields and blew the Arbiter out of the room. However, with the help of a dying Sergeant Johnson and his Spartan Laser, Spartan-117 managed to destroy Guilty Spark and start the firing sequence of the new Halo. He and the Arbiter then took Johnson's Warthog and rushed towards the Dawn as the incomplete Halo powered up and started breaking apart. The two drove their way through hordes of battling Flood and Sentinel drones, with the ring world literally falling to pieces around them. The two heroes made it onto the Dawn, where the Arbiter was almost crushed by a Scorpion Tank due to the sudden acceleration of the ship. Agility and a pair of crates saved him. Spartan-117 then inserted Cortana into a holotank and she activated the Dawn's engines. The Arbiter made his way to the bridge of the ship and took her into Slipspace just as the new Halo fired, with Master Chief almost being crushed by the same tank which descended through the cargo hold and into space. However, the Slipspace portal collapsed as the Dawn entered it, and while the forward half with the Arbiter made it to Earth, the rear half fell out of Slipspace at an unknown location, with Cortana and Spartan-117 floating into the dark abyss.

The Battle of the Ark ended the Human-Covenant War. Months later, a monument was erected near the remains of Voi in remembrance of those who died in the line of duty, including Spartan-117 who was labeled MIA. The Arbiter, the Shipmaster and their brethren then departed Earth for Sanghelios.

Aftermath
"For us, the storm has passed. The war is over. But let us never forget those who journeyed into the howling dark, and did not return. For their decision required courage beyond measure; sacrifice, and unshakable conviction that their fight, our fight, was elsewhere. As we start to rebuild, this hillside will remain barren. A memorial to heroes fallen. They ennobled all of us, and they shall not be forgotten."

- Fleet Admiral Terrence Hood in the memorial ceremony

Installation 00 and the Flood
The firing of the Halo ring caused unprecedented damage to the Ark while sterilizing the installation of the Flood forces around and on it, including the Gravemind commanding the massing Flood amid the battle. Over two years later on March 20, 2555, during Operation: FAR STORM, Luther Mann and N'tho 'Sraom arrived at the Citadel to stop the Halos from firing. Scattered around the basin were the remains of human and Covenant vehicles left over from the battle, including the empty husks of the two Scarabs.

Forward Unto Dawn
The Portal between Installation 00 and Earth collapsed while was still inside it. As a result, the ship was cut in half; the front arriving at Earth and the back half being lost in space. The Arbiter, sitting on the bridge at the time, was part of the front half but, without any engines, soon crashed into the ocean. However, John-117 and Cortana were in the rear half and were declared MIA by the UNSC. In reality, they had survived the Portal's collapse. John-117 went into cryo-sleep while Cortana activated an emergency locator beacon indicating their status. After drifting in an unknown region of space for over 4 years, the rear half of the Dawn was caught in the gravity well of a Forerunner shield world known as Requiem.

Legacy
"Jerome-092"

A monument was made near the town of Voi, not far from the portal structure. It read, "In memory of those fallen in the defense of Earth and her Colonies. March 3, 2553." On it were photos of UNSC personnel who went through the portal but did not return; John-117 was honored with an etching of the number "117" and an erroneous Master Chief Petty Officer of the Navy badge taped next to the number. With the exception of Thel 'Vadam, the Sangheili were not present at the dedication service, instead remaining aboard Shadow of Intent. After the ceremony, Lord Hood, despite being unable to forgive the Sangheili for what they did to humanity at the beginning of the war, shook 'Vadam's hand and thanked him for standing beside the Master Chief at the Ark. The Arbiter then departed to Shadow of Intent, and joined Rtas 'Vadum on the bridge, both agreeing to return to Sanghelios to ensure its safety. Thel 'Vadam was given command of the carrier and all Sangheili onboard departed for their homeworld.

In March 2555, the Ark's monitor, 000 Tragic Solitude, sought revenge against humanity for damaging the Ark years prior. To do so, the ancilla placed the remaining Halos on a brief countdown to activation, prompting a joint UNSC-Swords of Sanghelios mission to the installation to stop the rings from firing. After Solitude's plan was thwarted, the UNSC established research facilities on the Ark.

The Banished arrived on the Ark in November 2558, killing UNSC personnel across the installation. In March 2559, the crew of the newly arrived engaged the Banished with help from Isabel, the logistics AI of one of the UNSC research facilities. Approximately six months after the initial hostilities with Spirit of Fire, a Banished patrol encountered a number of surviving Flood forms. This led to a desperate struggle between the Banished and the parasite.

Ships
UNSC

Sangheili
 * Shadow of Intent
 * Pious Inquisitor

Covenant
 * Twilight Compunction
 * Gathering of Praise

Units
UNSC
 * UNSC Home Fleet
 * 105th ODST Division
 * 7th Shock Troops Battalion
 * 11th Marine Force Reconnaissance/ODST
 * S4/BLCE/1/7
 * S4/BRT/1/7
 * Alpha Company
 * Charlie Company

Allied Sangheili
 * Fleet of Retribution

Covenant
 * Truth's fleet

Personnel
UNSC
 * Commander Miranda Keyes
 * Master Chief Petty Officer John-117
 * Cortana
 * Lieutenant Hocus
 * Sergeant Major Avery Junior Johnson
 * Gunnery Sergeant Reynolds
 * Gunnery Sergeant Stacker
 * Private First Class Chips Dubbo

Fleet of Retribution
 * N'tho 'Sraom
 * Shipmaster Rtas 'Vadum
 * Arbiter Thel 'Vadam
 * Usze 'Taham

Covenant
 * Prophet of Truth
 * Cethegus
 * Hekabe and his family clan

Forerunner
 * 343 Guilty Spark
 * Mendicant Bias
 * 000 Tragic Solitude

Flood
 * Gravemind

List of appearances

 * Halo: First Strike
 * Petra
 * Halo 3
 * Halo Legends
 * Origins
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * From the Office of Dr. William Arthur Iqbal
 * Halo: Broken Circle
 * Halo: Hunters in the Dark
 * Halo Mythos
 * Halo: Tales from Slipspace
 * Dominion Splinter
 * Halo Wars 2
 * Halo: Envoy
 * Halo: Legacy of Onyx