Raid on Installation 04B

The Raid on Installation 04B was a small engagement between the UNSC-Covenant separatist alliance, the Flood and later the Forerunner Sentinels acting under 343 Guilty Spark's orders. It took place immediately after the raid on High Charity and marked the end of both the Battle of Installation 00 and the Human-Covenant War.

Battle of Installation 00
After realizing that the Prophet of Truth had gained access to the Ark, a joint UNSC-Covenant separatist attack force was sent through the Portal to combat the Covenant loyalist force there, and stop the Covenant form activating the Halo Array and destroying all sentient life in the galaxy.

The combined forces of the UNSC-separatist alliance was enough to completely destroy the Loyalist forces and prevent the Halo Array from firing. However, the arrival of the Flood hive on High Charity changed the course of the battle. John-117 set out for High Charity. His goal was to retrieve a copy of Installation 04's index from the captured AI Cortana and fire off the newly rebuilt Halo, completely destroying the Flood in and around the Ark.

Raid on High Charity
John-117 landed in High Charity and combated Flood forces deep into their hive. After fighting through waves of Flood forms, he retrieved Cortana, and therefore, the activation index she acquired during the events of the original Battle of Installation 04. The SPARTAN then set High Charity's secondary reactors to explode. He met up with Thel 'Vadam, who had also ventured into the hive to help him, and they took off in a Pelican to activate Installation 04B and destroy the Flood. As they left, High Charity exploded, killing nearly all of the Flood there. Meanwhile, the human and separatist survivors from Installation 00 were evacuated to the separatist assault carrier Shadow of Intent which headed back to Earth through the portal.

Battle
John-117 piloted the damaged Pelican and crash-landed the dropship nearby the Installation's control room. At the same time, Sergeant Major Avery Johnson landed the on the Installation, far away from the control room. On foot, John, along with Cortana and Thel 'Vadam, made their way to the control room. The Gravemind, succumbing from the damage inflicted upon him from the High Charity explosion, sent waves of Flood dispersal pods to prevent the activation of the Installation. The SPARTAN and the Arbiter fought through the Flood forces as they progressed to the top of the tower, with some assistances from the Sentinels and Sergent Johnson. Once at the top, the team met up with the sergeant, secured the area and entered the control room.

Once inside, the team hesitantly tried to activate the Installation immediately. 343 Guilty Spark, after realizing that firing the partially-completed Installation would destroy the megastructure as well as the Ark, turned against the team. His initial attack mortally wounded the sergeant and blasted the former Arbiter out of the control room. John-117 was severely injured by the initial blast to the point of draining his shield. The SPARTAN was locked into a battle with the rampant Monitor and struggled to destroy it. The mortally wounded Sergeant Johnson took the rogue Monitor by surprise with his Spartan Laser, temporarily incapacitated the Forerunner construct. John, seizing the moment, used the sergeant's Spartan Laser to destroy Guilty Spark. John tended to the grievously wounded sergeant, whose dying words being "send me out, with a bang." Cortana gave her condolence and activated the Installation using the Activation Index.

As the team exited the control room, they find themselves having to battle against the Sentinels and the Flood. The team made their way out of the vicinity of the tower and commandeered an abandoned Warthog left behind by Sergeant Johnson. With the vehicle, the team rode to the Forward Unto Dawn as fast as they could, passing through a labyrinth of construction tunnels, and collapsing platforms. The team eventually made it to the Dawn by crash-landing into the ship's cargo bay. Thel quickly climbed to the bridge and started piloting the ship to safety, while John struggled to hold on in the cargo bay of the vessel. As they approached the Portal, the Installation fired.

Aftermath
This battle marked the end of the Flood threat. As the incomplete Installation 04B fired, it obliterated the Ark, along with all Flood and Sentinel forces as well as any surviving Covenant forces present on both constructs.

While Forward Unto Dawn was entering the Portal the field collapsed, severing the ship in two. The bow, with Thel inside, made it to the exit coordinates above Earth and crashed into the Indian Ocean. The stern section was less fortunate, being thrown out of the collapsing slipspace field on the way. John and Cortana were trapped in the wreckage as it drifted in space for several years, eventually being caught in the gravity of Requiem, a Forerunner shield world, in 2557. This led to a series of series of skirmishes as the Master Chief and Cortana struggled to find a way back to human space, opposed by a reformed Covenant sect which had sought out Requiem and the Promethean forces within the shield world.

List of appearances

 * Halo 3
 * Halo Legends
 * Origins