Battle of Installation 04

The Battle of Installation 04 was the name given to a theatre between the UNSC and the Covenant on the surface of the Forerunner construct Installation 04.

The Flood and the Forerunner Sentinels joined the battle during its later part.

Space battle
Following the UNSC's disastrous defeat at Reach and the loss of a third of her tech staff, the made an apparently blind jump through Slipspace from where they would then make their way to Earth. In reality it was planned by the AI Cortana, using coordinates found in an artifact found on Sigma Octanus IV. The Autumn and the approximately 1,100 humans on it were followed, and upon arriving in orbit above the planet Threshold on September 19, 2552, were intercepted by the pursuing Covenant vessels.

The vessel managed to destroy four of the Covenant vessels and force one, the Truth and Reconciliation to retreat for repairs. As Covenant forces began boarding the ship, Captain Jacob Keyes ordered Thom Shephard to release Master Chief Petty Officer John-117 from his Cryo-chamber. Shephard was later killed by a conduit explosion. His friend, Sam Marcus, was working in the observation theater overlooking the Cryo-chamber when he was hosed down with plasma fire.

The Master Chief then proceeded to the Bridge of the Pillar of Autumn, where he was joined with the shipboard AI Cortana. With the MAC cannon disabled due to heavy enemy fire, Keyes initiated Cole Protocol Article 2, and evacuated the ship. Carrying Cortana, the Chief fought his way through the rapidly decaying Pillar of Autumn. He then evacuated to the recently discovered Installation 04 aboard Bumblebee lifepod Lima Foxtrot Alpha 43. The pod's descent systems failed in mid-flight and the following impact killed all of the marines on board, except for the Master Chief.

The dropship pilots, led by Foe Hammer, decided to take their Pelicans down instead of going down in the lifeboats. After dealing with a few Covenant hostiles, they successfully reached their ships and escape the Pillar of Autumn on them.

Captain Keyes flew the Autumn in most of the way to the ring manually, then abandoned the ship to crash on Halo under the control of some subroutines Cortana left behind for that very purpose. Unknown to him and his bridge crew, they were being followed by a cloaked Elite that planned to capture him, but Keyes detected the Elite on the way down and killed it personally. The rest of the Covenant boarders abandoned the Pillar of Autumn as it went down. The ship crash landed in a desert on Halo mostly in one piece, but damaged beyond repair and with no hope of ever taking off again.

Seizure of Alpha Base
Meanwhile, a battalion of ODSTs led by Major Antonio Silva and Lieutenant Melissa McKay "helljumped" to Halo in their Human Entry Vehicles. Once on the ground, the ODSTs made contact with Major Silva and established a temporary headquarters. Silva then instructed McKay to capture a Covenant-held butte that Silva's AI had projected during his descent. The rest of the battalion stayed at the headquarters established landing zones, to allow Pelican Dropships to pick up troops for an aerial assault on the base. The Covenant then staged an assault on the Helljumpers, sending one-hundred Ghosts and later, Banshees. The marines fended off the attack, killing more than 50 Sangheili, including a Zealot, but suffered twenty-three killed and sixteen wounded. McKay lost only one Marine, while the fourth company lost a few more performing an aerial assault on the butte.

Under orders from Major Silva, Melissa McKay led her team of ODSTs in a ground assault on Alpha Base. They fought their way up a ramp spiraling up the butte, while the Covenant attempted to eliminate the humans by raining plasma grenades on them. Meanwhile, Silva began loading troops onto the Pelicans for an aerial insertion onto the butte, halted briefly by the Covenant attack.

After fighting their way up the butte, McKay's team was halted by a rockfall. However, a door set into the side of the butte allowed access, and McKay used a rocket launcher to detonate a large number of Covenant explosives, wiping out any Covenant inside. Once inside, they rode a lift up to the surface, where they found that Silva had arrived and had eliminated the remaining Covenant.

Betrayal
Upon arrival on the ring, Captain Jacob Keyes, a marine fire team led by Corporal Wilkins and the surviving command crew were able to fend off Covenant troops, who were attempting to capture them. However, one officer, Ensign Ellen Dowski was beginning to crack, and wanted to surrender to the Covenant. Believing that she might stir up similar thoughts in the marine fire team, the team tied her up and left her to surrender to the Covenant herself. However, upon discovering that the gulch they landed in was a box canyon the humans were captured and executed by the Covenant, save for Captain Keyes, who was taken for interrogation.

Rescue of Stranded Survivors
After crash-landing on the ring, the Master Chief found that he and Cortana were the only survivors of his life pod. The Chief headed out to get away from Covenant patrols and after a brief skirmish with a small Covenant patrol, found a group of survivors under attack in a structure nearby. The Chief defeated the Covenant attackers and helped the survivors, including Sergeant Johnson, fend off three more waves of Covenant forces before Echo 419 finally arrived to pick them up. Witnessing three more lifepods flying overhead, Cortana had Foe Hammer disengage her Warthog to make it easier for the Chief to find the survivors in time. He was joined by two Marines who manned the gun and rode shotgun.

After making his way through an underground structure and another brief skirmish with Covenant forces, the Chief found another lifepod, this one abandoned with no sign of survivors or bodies. In a nearby structure on top of a cliff, the Master Chief found the survivors from the lifepod under attack by Covenant. After clearing out the structure, the survivors emerged and Echo 419 picked them up. She also reported the locations of the other survivors.

After an encounter with two Covenant Banshees, the Master Chief found another group of survivors in some hills and after clearing the area, joined them on the hill. A Covenant dropship deployed more enemy troops, but the Marines and the Chief had the higher ground and sniper rifles and defeated the Covenant easily. Again Echo 419 dropped by after the fight and picked up the survivors.

The Chief located the last group hiding in a rock formation and helped them fend off several waves of Covenant forces. Echo 419 then picked up everyone, including the Chief. At the same time, Cortana, having hacked into the Covenant Battlenet, discovered that Captain Keyes was alive but had been captured by the Covenant. The survivors returned to Alpha Base to plan a rescue mission for the captain.

Raid on the Truth and Reconciliation
The UNSC launched a mission to recover their captured leader, Keyes, who was being held aboard the CCS-class Battlecruiser the Truth and Reconciliation. Under the cover of night, Master Chief and a squad of ODSTs boarded the ship via its gravity lift. After fighting through the maze-like corridors, the team captured the ship's command center. The ODSTs stayed behind while Master Chief went ahead and freed Captain Keyes and several other Marines. When they returned to the bridge, however, they found that the ODSTs had been slaughtered by Stealth Elites. Furthermore, Echo 419 was under attack from Covenant air patrols and was unable to pick them up. In order to escape, the Chief and Keyes hijacked a Covenant dropship and used it to return to Alpha Base.

Battle of the Silent Cartographer
The following day, the crew of Pillar of Autumn launched an attack on the Silent Cartographer island, in their attempt to uncover the location of the ring's Control Room. Fighting their way through the heavily defended Covenant positions, the Master Chief and a handful of Marines, supported by Echo 419 and Bravo 22, discovered the location of Alpha-Halo's Control Room. However, a pair of Covenant Dropships landed and engaged the defenders of the LZ, apparently killing most of the Marine assault group.

Flood Containment Facility
Meanwhile, Captain Jacob Keyes, along with 2nd Squad landed nearby in Pelican dropship Victor 933 and proceeded to infiltrate a structure in a swamp, which they had been told by a captured Elite named 'Qualomee was a weapons cache. They later met up with Staff Sergeant Avery Johnson's "Fire Team Charlie", who had proceeded to the structure and engaged the Covenant they encountered in the upper levels of the facility. After receiving a transmission from a troubled marine present further into the facility, they set out to provide aid.

While exploring the lower levels, the UNSC forces eventually come across a sealed door, locked down by the Covenant. With increasing curiosity the UNSC opened the door and explored the room. After a short time, the "weapons cache" Keyes was looking for revealed itself in the form of the Flood. The Covenant had sealed the facility after they had unwittingly released the monstrous parasite. The Flood attacked second squad who barely got a message to Keyes and escaped. However the message was too late as the Flood attacked Keyes' Fire Team, infecting Keyes along with Privates Riley, Kappus, Jenkins, Mendoza, and Bisenti, and about 3 others before a pair of marines got out of the room, one of whom was killed just outside and one Marine who escaped by playing dead. Sergeant Johnson also escaped due to his immunity to the Flood because of his Boren's Syndrome.

Assault on the Control Room
Meanwhile, the Master Chief was inserted into a network of tunnels by Foe Hammer. After fighting his way through, he received a radio transmission from Fire Team Zulu, who were pinned down in a valley. The Master Chief rushed to assist, fighting his way across a bridge to an elevator, which he rode down to the floor of a canyon. There, he fought off a Wraith Tank, two Shades, a Ghost and multiple ground forces. The Chief and the Marines fought through a system of adjacent canyons, until reaching a dead end, where the Chief left Fire Team Zulu for evac. He then headed towards a large pyramid, on top of which was the Control Room. Upon reaching the room, Cortana accessed Halo's systems and discovered a horrible secret buried in the ring, and that Captain Keyes had walked right into it.

The Flood
Three hours after the assault on the Control Room, the Master Chief arrived near Victor 933's crash site on board Echo 419. He then entered the lightly guarded structure, being watched by the Flood. After entering the Containment Room, he found Private Jenkins' helmet with a built in video camera. After seeing the gruesome events through the eyes of Jenkins, the Chief was attacked by the remaining Flood that spewed out of nearby doors. The Master Chief fought them off and then proceeded to escape the facility, combating Infection and Combat forms. The Master Chief soon caught up with Corporal Lovik's squad, who were advised by Echo-419 to take refuge at a nearby tower.

The survivors fought their way through the swamp in search of the tower, which would be the Evac site for E419. After making it to the structure, the Marines were aided by a mysterious ally, floating constructs known as Sentinels. The Sentinels, commanded by a Monitor, 343 Guilty Spark, defended the marines, eliminating any Flood in the vicinity of the tower. The Monitor then teleported the Master Chief into the Library, referring to him as "Reclaimer".

Covenant forces from the crashed Spirit dropship fled the Containment facility, but were all likely wiped out.

Flood forces in the vicinity of the swamp were wiped out. However, the majority of Flood forces escaped the Containment facility and spread across the Installation, infecting any appropriate hosts. The few surviving UNSC forces were evacuated by Echo-419. Captain Keyes was later taken to the Truth and Reconciliation by the Flood.

Battle of Alpha Base
The UNSC forces, led by Lieutenant McKay staged a raid on the crashed Pillar of Autumn, in order to gain extra supplies of rations, weapons, ammunition, and fuel. They succeeded in destroying a large force of Ghosts and a Spirit dropship as well as killing many Covenant troops. They then retrieved a large squad of Warthogs, trailers and four Scorpion tanks from the cruiser's vehicle bays and drove them in a convoy to Alpha Base. At a trio of hills, the Covenant attempted to ambush the humans, attempting to destroy the convoy with Wraith mortar tanks, Banshees and Ghosts. Despite the size of the attack, The Covenant forces only managed to inflict moderate damage before losing the tanks and a large portion of their ground forces to the Scorpions' return fire. The tanks would later see use around the ring world, most notably in the defense of Alpha Base.

Meanwhile, the Covenant sent the captured Pelican Charlie 217 and its captured pilot Lt. Rick Hale to insert 30 Spec Ops Elites commanded by Zuka 'Zamamee to assassinate the (absent) Master Chief and clear a landing zone for six Spirit Dropships. Although six of the Elites managed to escape into the base, the rest were killed when the ODST forces flooded Charlie 217 with jet fuel before igniting it, killing the Elites that had remained on the platform. The surviving Covenant forces had by this time neutralized the human control rooms, and liberated a large number of Covenant prisoners.

However, the MLA auto-cannons and various other defense systems managed to destroy one of the Spirit dropships and killed many Covenant troops in the others. Groups of rocket launcher marines then added to the casualties. Despite their numerical superiority, the Covenant forces landing on the butte were soon either killed or captured, and the assault on Alpha Base stalled.

The Covenant ground assault, lead by a Zealot Field Master Noga 'Putumee, made significant progress against the humans due to their use of Spirit dropships to clear the way ahead of the ground forces. However, the seeming rout was designed to lure the Covenant into the firing range of a pair of concealed Scorpion main battle tanks, which then tore into the ranks of the aliens and inflicted major casualties. Field Master 'Putumee was killed by the third shot from the tanks, throwing the alien forces into chaos, and of the 150 infantry with him, only a few survived to retreat.

Meanwhile, the Covenant Spec Ops team and the freed Covenant troops ran into a Marine ambush in which all members of both sides were killed other than the Elite Zuka 'Zamamee and the Grunt Yayap. By this time, however, the Covenant ground assault was in full retreat.

The only known Covenant survivors of the aerial assault were Zuka 'Zamamee and the grunt Yayap who then fled the battlefield in a recaptured Banshee.

The Library
343 Guilty Spark transported the Master Chief to the Library of Installation 04, where he was tasked with locating and retrieving the Activation Index. Proceeding into the bowels of the huge structure, he fought off wave after wave of Flood, before the Monitor called in Sentinels. He reached a massive elevator that transported him to the second floor of the facility, and fought the Flood on that floor. Upon reaching the Central shaft of the Library, he rode another elevator down to the Index and retrieved it. He then was then teleported back to the Control Room.

Two Betrayals
Master Chief, after teleporting back to the Control Room, proceeded to activate Installation 04. However, Cortana, who, after spending twelve hours in the control room, had discovered Halo’s true purpose, stopped him just in time. After stealing the Activation Index, she told the Chief that Halo will wipe out all life in the galaxy, turning the Chief against the Monitor. Spark ordered his Sentinels to take the Spartan's head, and the AI inside his helmet. After destroying the Sentinels in the Control Room, Cortana told the Chief to destroy three Phase Pulse Generators to buy some time, in case the Monitor found a way to activate Halo without the index. While Cortana tried to locate the Pillar of Autumn's crash site, the Chief hijacked a Covenant Banshee and set out to destroy the generators.

Upon the destruction of the third generator, Cortana hacked into the teleportation grid that ran across Halo's surface, and teleports the two to the damaged Covenant cruiser Truth and Reconciliation to rescue Captain Keyes.

Ambush
Silva wanted to engage the Covenant in a medium conflict that would "take the hurt to them. Nothing big, not yet anyway, but the kind of pinpricks that still draw blood", leaving Lieutenant McKay to plan out the mission. She decided to use bait in order to draw the Covenant in with "crashed" Pelicans (Charlie 217's burned-out remains), mock-injured Marines, and a phony distress call. Since Wellsley believed that the Covenant took the Marine force seriously after the Raid on the Truth and Reconciliation, they should monitor human radio traffic and regular recon flights, allowing them to easily pick the bait.

First, the preparation of arranging for the bait took several hours (They had to scourge for bodies of comrades killed on the butte for "volunteer" casualties.) Sure enough, thirty minutes into the wait, McKay saw a Banshee and signaled for the operation to commence. Members of the third squad, some of whom had mock-injuries, pantomimed surprise and hurried back to cover as the Banshee shot plasma fire at them. The Banshee then went away, presumably to tell the Covenant about a new Human location.

Later, a Spirit Dropship appeared, dropping Jackals, Elites, Grunts, and a pair of Hunters. These were a surprise, though McKay quickly ordered all the heavy weapons and sniper fire to concentrate on the "walking tanks". Soon enough, they went down. However, the dropship returned and hosed the entire area, forcing the Helljumpers to take cover. Thus encouraged, the Covenant rushed into the rocks to engage. However, the snipers managed to pick off five alien soldiers before the dropship exacted the position. Two snipers were killed by plasma, and another was wounded.

Soon, the mission turned ugly, as the Covenant engaged in hide-and-seek with the Marines. Just as McKay was about to order a retreat, something even worse appeared.

Suddenly, the bizarre creatures, also known as the Flood, attacked both groups. While the Covenant had experience with the Flood, the Helljumpers simply had never seen them before. Three members of the second squad were going down under the Infection forms, while another was being massacred by the Combat forms. Confused pleas and requests for extraction filled the radio, tripling the radio traffic. McKay received her first look when she noticed a Grunt with two Infection forms; she put down the trio with a sustained burst. However, then, Pvt. Jenkin's Combat form jumped out, hoping to be killed by the Lieutenant. In order to collect a specimen, she sidestepped and restrained the Flood form. In order to kill the Flood, the Marines and Covenant joined forces, and eliminated the Flood after 15 minutes. Then, they proceeded to return to their hide-and-seek. Finally, with half the Marines killed, the UNSC claimed a victory.

Final Actions
"We did what we had to do... for Earth. An entire Covenant armada obliterated, and the Flood... we had no choice."

- Cortana

Return to the Truth and Reconciliation
The Master Chief and Cortana arrived at the Truth and Reconciliation so they could save Keyes and have him activate the Pillar of Autumn's self-destruct sequence. They found themselves in the middle of a battle between the Covenant and the Flood for control of the CCS-class Battlecruiser. They fought through their enemies and entered the ship via the gravity lift. They made their way to the bridge where they discovered to their horror that Keyes had become part of a Proto-Gravemind. With no other choice, the Master Chief punched a hole in the Proto-Gravemind and took Keyes's Command Neural Interface. This would allow them to activate the self-destruct sequence themselves. The Master Chief and Cortana then fought their way to one of the hangars, stole a Banshee and escaped to the Pillar of Autumn.

Capture of the Truth and Reconciliation
By September 22, only 312 humans (236 marines, 76 naval personnel) remained alive at Alpha Base. To escape back to Earth, they attacked the Flood-infested Truth and Reconciliation despite the AI Wellsley's warnings. The surviving marines were deployed in the area surrounding the Truth and Reconciliation, which had been restored to working order by that point. The surviving Pelicans landed in the hangar bays, and the Marines took control room of the ship. Meanwhile, McKay's troops stormed the area surrounding the grav lift, killed the security team guarding it, and entered the ship. Using the schematics from the previous raid, the humans quickly secured the ship's engine room, as well as 80% of the ship. While the human technicians studied the ship's controls, and Wellsley activated the ship's engines, a small group of Flood attacked the engine room. The Flood were quickly subdued, but the attack caused McKay to urge Major Silva to set the ship down and eradicate the Flood on board. Silva, however, believed that intact Flood specimens would gain him an instant promotion back on Earth and refused to listen. Once McKay returned to her post, Lieutenant Commander Gail Purdy pointed out a fiber-optic passage that connected the engines to the command center. McKay, knowing the Flood could not be allowed to reach Earth, severed the passage, and destroyed the ship with all hands, Human and Covenant, as well as any remaining Flood on board.

Destroying the Autumn
Having escaped the Truth and Reconciliation, the Master Chief promptly returned to the Pillar of Autumn, crashing his stolen Banshee into the side of the ship (mainly to annoy Cortana). He then fought the Flood, the Sentinels, and the Covenant and entered the ship's bridge. Once he had dispatched the Covenant Security Team, he uploaded Cortana into the control system. She started the ship's self destruct sequence, only to discover to her dismay that the Monitor was on board. Guilty Spark began to tap into the ship's systems and data arrays, and stopped the self destruct sequence. Cortana deduced that the Monitor was in Engineering and was trying to take the Autumn's engines offline. The Chief decided to overload the engines by manually cracking the engine's magnetic containment fields.

The Master Chief fought his way through Cryo B to reach Engineering. Following Cortana's instructions, he destroyed each of the four engines by throwing grenades (or firing rockets) into the open shafts, destabilizing the containment fields. Cortana predicted that they had 15 minutes before the engines detonated. The Chief headed for the shaft of elevator V-1269 where he was ambushed by Zuka 'Zamamee. The trap almost succeeded, but with Cortana's help, the Chief killed Zuka 'Zamamee by knocking the Elite to the bottom of the shaft. The Chief then rode the elevator to a Class Seven Service Corridor located along the ship's dorsal structure. Using a Warthog, he drove along the length of the Corridor to External Access Junction 4C where Echo 419 was to pick the Chief up one last time. However, two Banshees shot down the Pelican, killing Foe Hammer. The Chief was then forced to drive another kilometer to Launch Bay Seven, where a single Longsword fighter was docked. The Spartan successfully boarded the ship and escaped Halo. Moments later, the Autumn's engines detonated, destroying Halo and bringing the battle to an end.

Aftermath
After the destruction of Installation 04 and John-117's successful escape, Cortana scanned the ring's debris field for survivors. Soon, multiple Covenant capital ships entered the system. Cortana discovered several cryo pods jettisoned from the Pillar of Autumn during the initial battle, one of which contained Linda-058, and a Pelican dropship with several survivors. John-117 picked up the survivors in the Longsword, and with their help, boarded and hijacked the Covenant flagship Ascendant Justice and headed for Reach.

From a strategic standpoint, the Battle of Installation 04 was a major victory for the UNSC. The Covenant lost dozens of ships and many thousands (possibly hundreds of thousands) of ground troops, while the UNSC lost only one ship and perhaps little over a thousand troops. Furthermore, the UNSC gained tactical information on Covenant technology, and more importantly they learned about the Flood and the purpose of the Halo Array.

The battle on Alpha Halo resulted in more than just a UNSC victory, however. It sparked a series of events that would alter the course of the entire war. Thel 'Vadamee, the Supreme Commander of the Fleet of Particular Justice, was stripped of rank and branded as a heretic for his failure to protect Halo. Instead of executing 'Vadamee, however, the Prophet of Truth made him an Arbiter. The Arbiter would play a major role in the events of Halo 2 and Halo 3, as would 343 Guilty Spark, who survived Halo's destruction. Furthermore, outside the galaxy, the Ark started to construct a new Halo to replace the one destroyed in the battle. It was on this replacement Halo that the final battle of the war would take place.

Survivors
It is assumed that only 8 members of the Pillar of Autumn were in space and therefore survived the blast, 6 of which were on a Pelican, two Spartans, Linda, who was in a Cryo pod, and the other one, Master Chief, was on a Longsword fighter. Every other person at the battle presumably died when Installation 04 was destroyed. However, since Gunnery Sergeant Pete Stacker and Private Chips Dubbo, among others, have been seen again in later games, it can be assumed that there were other survivors.

However, it is explained in Halo: The Flood and Halo: First Strike, that the Autumn was operating as a skeleton crew, as the remaining non-essential crew remained in cryo. When the Covenant infiltrated the ship, most of the crew were still asleep and their tubes were shot into space to save them from being killed in the crash.

The Chief managed to retrieve 3 tubes, one containing Linda. The people in the other 2 had died in sleep due to malfunctions. It is not known whether this was a malfunction in one of the cryo storage rooms, or if it happened to almost every tube.

It is unknown how many occupied tubes survived Halo; however, most, if not all, would have been destroyed by the time High Charity arrived.

UNSC

 * Pillar of Autumn staff:
 * Crew
 * Captain Jacob Keyes
 * Lieutenant Commander Gail Purdy
 * Lieutenant Dominique
 * Lieutenant Hall
 * Lieutenant Elias Haverson
 * Lieutenant Aki Hikowa
 * Ensign William Michael Lovell
 * Chief Petty Officer Thom Shepard
 * Petty Officer First Class Mary Murphy
 * Petty Officer Third Class Cho
 * Petty Officer Third Class Sam N. Marcus
 * Petty Officer Third Class Pauley
 * Crewman Abiad
 * Crewman Singh
 * Crewman Wang
 * Flight Crew
 * Crew Chief Cullen
 * Flight Officer Captain Carol Rawley
 * Flight Officer Mitchell
 * Warrant Officer Shiela Polaski
 * Lieutenant "Cookie" Peterson
 * Lieutenant Rick Hale
 * Lieutenant Frye
 * Ensign Ellen Dowski
 * Marines
 * Major Antonio Silva
 * First Lieutenant Melissa McKay
 * Second Lieutenant Dalu
 * Second Lieutenant Oros
 * Master Chief Petty Officer John-117
 * Master Sergeant Lister
 * Gunnery Sergeant Pete Stacker
 * Gunnery Sergeant Waller
 * Staff Sergeant Avery Johnson
 * Staff Sergeant Marvin Mobuto
 * Sergeant Thomas Chang
 * Sergeant Tink Carter
 * Sergeant Corly
 * Sergeant Parker
 * Corporal Locklear
 * Corporal Lovik
 * Corporal Wilkins
 * Lance Corporal "Snaky" Jones
 * Private First Class Chips Dubbo
 * Private First Class M. Fitzgerald
 * Private First Class Hosky
 * Private First Class Wallace A. Jenkins
 * Private First Class Suzuki
 * Private Bisenti
 * Private Kappus
 * Private Manuel Mendoza
 * Private Marie Postly
 * Private Riley
 * Private Satha
 * Al-Thani
 * Dawkins
 * "Doc" Valdez
 * Murphy
 * Yutrzenika

Covenant

 * Fleet of Particular Justice
 * Thel 'Vadamee
 * Zuka 'Zamamee
 * Noga 'Putumee
 * Soha 'Rolamee
 * Yayap
 * Gagaw
 * Linglin
 * Igido Nosa Hurru
 * Ogada Nosa Fasu

Forerunner Constructs

 * 343 Guilty Spark
 * Millions of Sentinels

Flood

 * At least one Proto-Gravemind
 * Thousands of Combat Forms
 * Thousands of Carrier Forms
 * Millions of Infection Forms

Related Articles

 * Human-Covenant War
 * Installation 04
 * Raid on the Truth and Reconciliation
 * Battle of the Silent Cartographer
 * Battle of Installation 05