Editing Battle of Installation 05

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{{Era|HCW|FA}}
{{Cleanup}}
{{Quad battle infobox
|prev= [[Battle of the Gas Mine]]
|conc= [[First Battle of High Charity|First Battle of ''High Charity'']], [[Great Schism]], [[Battle of Earth]]
|next= [[Battle of Onyx]], [[Battle of Mare Erythraeum]]
|name= Battle of Installation 05
|image=[[File:Installation 05.jpg|300px]]<br>At the conclusion of the Battle of Installation 05, Installation 05 sends a partial pulse into space.
|conflict=[[Human-Covenant War]], [[Great Schism]]
|date= November 2-November 3, [[2552]]
|place= Installation 05
|result=Strategic UNSC/Covenant Separatist victory
*Beginning of Covenant civil war
*Fragmentation of the Covenant
*Sangheili form an alliance with the UNSC
*Halo Array enters standby mode 
Tactical Flood victory
*Flood successfully escape Installation 05 
*High Charity assimilated by the Flood  
|side1=*[[United Nations Space Command]] 
*[[Covenant Separatists]] (After the outbreak of the Great Schism)
|side2=*[[Covenant Empire]]
*[[Covenant Loyalists]] (After the outbreak of the Great Schism)
|side3=[[Forerunner]]
|side4=[[Flood]]
|commanders1=*[[Commander]] [[Miranda Keyes]]
*[[Master Chief Petty Officer|Master Chief]] [[John 117]]
*[[Cortana]]
*[[Sergeant Major Avery Junior Johnson]]
*[[Thel 'Vadamee]] (After the outbreak of the Great Schism)
*[[Rtas 'Vadumee]] (After the outbreak of the Great Schism)
|commanders2=*[[Prophet of Truth]]
*[[Tartarus]]†
*[[Prophet of Mercy]]†
*[[Prophet of Regret]]†
*Thel 'Vadamee (Before the outbreak of the Great Schism)
*Rtas 'Vadumee (Before the outbreak of the Great Schism)
|commanders3=*[[343 Guilty Spark (Monitor)|343 Guilty Spark]]
|commanders4=*[[Gravemind]]
**[[2401 Penitent Tangent]] 
|forces1=*[[UNSC frigate]] (1)
**{{UNSCShip|In Amber Clad}}
***[[UNSC Marine Corps|Marines]] (companies-battalions)
****[[Orbital Drop Shock Trooper]]s (platoons-companies)
***[[John-117|SPARTAN-117]]
***[[M808B Scorpion MBT]]s
***[[M12 Warthog LRV]]s
*[[Reverence-class Cruiser|''Reverence''-class Cruiser]]s
**''[[Incorruptible]]'' (After the outbreak of the Great Schism)
*[[Covenant carrier]]s
**''[[Lawgiver]]'' (After the outbreak of the Great Schism)
*[[CCS-class Battlecruiser|CCS-class Battlecruiser]]s
*[[Covenant destroyer]]s
**''[[Rapturous Arc]]'' (After the outbreak of the Great Schism)
*[[Sangheili]] (After the outbreak of the Great Schism)
*[[Mgalekgolo]] (Partially after the outbreak of the Great Schism)
*[[Unggoy]] (Partially after the outbreak of the Great Schism)
*[[Scarab]]
*[[Wraith]]s
*[[Spectre]]s
*[[Banshee]]s
*[[Ghost]]s
|forces2=*''[[High Charity]]''  (Before the ''In Amber Clad'' crashes into it)
**[[Jiralhanae]]
**[[Kig-yar]]
**[[Yanme'e]]
**Sangheili (Before the outbreak of the Great Schism)
**Mgalekgolo (Partially after the outbreak of the Great Schism)
**Unggoy (Partially after the outbreak of the Great Schism)
*Wraiths
*Spectres
*Banshees
*Scarab
*Ghosts
*[[Second Fleet of Homogeneous Clarity]]
**[[Covenant assault carrier|Assault carrier]]s 
**[[Covenant frigate]]s
***''[[Tenebrous]]''
***''[[Twilight Compunction]]''
*[[Reverence-class Cruiser|''Reverence''-class Cruiser]]s
**''[[Incorruptible]]'' (Before the outbreak of the Great Schism)
*[[Covenant carrier]]s
**''[[Lawgiver]]'' (Before the outbreak of the Great Schism)
*[[CCS-class Battlecruiser|CCS-class Battlecruiser]]s
*[[Covenant destroyer]]s
**''[[Rapturous Arc]]'' (Before the outbreak of the Great Schism)
|forces3=*[[Sentinel]]s Minor, [[Sentinel Major|Major]])
*[[Enforcer]]s
*[[Sentinel Constructor Factory|Sentinel Constructor Factories]] (2+)
|forces4=*''[[High Charity]]''  (Before the ''In Amber Clad'' crashes into it)
*Unnamed [[CCS-class Battlecruiser|CCS-class Battlecruiser]]
*[[Flood]] forms
**[[Infection Form]]s
**[[Combat Form]]s
**[[Carrier Form]]s
**[[Gravemind]] Form (1)
|casual1=*UNSC ''In Amber Clad''
*Almost all Marines and ODSTs.
*Large number of Sangheili, Lekgolo, and Unggoy involved
*Large number of Scorpions and Warthogs
*Large number of Wraiths, Spectres, Banshees, and Ghosts
*Large number of assorted Separatist starships
|casual2=*''[[High Charity]]'' captured
*[[Prophet of Regret]] 
*[[Prophet of Mercy]]
*[[Tartarus]]
*Large number of Jiralhanae, Kig-yar, and Yanme'e
*Large number of Wraiths, Spectres, Banshees, and Ghosts
*Large number of assorted Loyalist starships
|casual3=*Large number of Sentinels
*Large number of Enforcers
*Sentinel construction factory
|casual4=*Large number of assorted Flood Forms
**Infection Forms
**Combat Forms
**Carrier Forms
}}

{{Quote|[[Cortana]], what exactly am I looking at?|Commander [[Miranda Keyes]]}}
{{Quote|That... is another Halo.|Cortana}}

The '''Battle of Installation 05''', also known as the '''Battle of Delta Halo''' (or the '''Battle for the Second Ring of the Gods''' among the [[Covenant Empire|Covenant]],<ref>'''[[Halo: Ghosts of Onyx]]''', ''page 241'' (standard size)</ref>) was a major engagement between the [[United Nations Space Command]], the Covenant, the [[Forerunner]]s, and the [[Flood]] on the Forerunner [[Halo Array|ringworld]] [[Installation 05]], otherwise known as "Delta Halo".

==Introduction==
At the beginning of the [[Battle of Earth]], the [[Prophet of Regret]] led [[Regret's fleet|a small fleet]] of two [[Covenant assault carrier|assault carrier]]s and thirteen [[CCS-class Battlecruiser]]s on an expeditionary raid that stumbled upon [[Earth]], humanity's homeworld and the UNSC's strongest fortress. After substantial ground, air, and space losses, Regret fled in [[Regret's assault carrier|his assault carrier]] over [[New Mombasa]] to Installation 05.

However, upon [[Fleet Admiral]] [[Terrence Hood|Hood]]'s order, five UNSC warships near New Mombasa were close enough to catch onto the assault carrier's rift before it terminated: three [[UNSC frigate]]s, the {{UNSCShip|In Amber Clad}}, {{UNSCShip|Paris}}, and the {{UNSCShip|Redoubtable}}, one [[UNSC corvette]], the {{UNSCShip|Coral Sea}}, and one [[UNSC Prowler]], the {{UNSCShip|Dusk}}, were able to enter the [[Slipstream space|Slipspace]] field, trailing Regret's assault carrier. 

Their shadowing, however, was not exactingly precise. Only the frigate ''In Amber Clad'' successfully trailed the assault carrier to Installation 05. The prowler ''Dusk'' arrived days later near the Covenant homeworld ship ''[[High Charity]]'', and the ''Coral Sea'', ''Paris'', and ''Redoubtable'' were nowhere near the engagement, most likely due to the imprecise physics of Slipspace and the UNSC's rather limited technology in that field.

==Regret==
===UNSC offensive===
Regret's assault carrier hovered over the installation, deploying [[Wraiths]], [[Ghosts]], [[Banshees]], and also companies of [[Sangheili]], [[Kig-yar]], [[Yanme'e]], and [[Unggoy]] by means of [[Phantom]] dropships. The Covenant ground forces fortified themselves in a series of Forerunner ruins and temple structures, even establishing [[Shade]]s for further defense.

Meanwhile, the ''In Amber Clad'' trailed behind, and after the assault carrier moved off, [[Commander]] [[Miranda Keyes]], captain of the ''In Amber Clad'', ordered a [[platoon]] of [[Orbital Drop Shock Trooper]]s and [[John-117]] to establish a landing zone near a series of ruins and temples on Installation 05 to allow [[Sergeant Major]] [[Avery Junior Johnson|Avery Johnson]] to bring in two flights of [[D77-TC Pelican|Pelicans]] and further expand the UNSC presence. The frigate made a quick pass-over of a segment of the ringworld, deploying a dozen [[Single Occupant Exoatmospheric Insertion Vehicle|SOEIV pods]]. Six survived the atmosphere of the ring, and only four personnel eventually survived the impact - SPARTAN-117 and three ODSTs. However, before they could land in the small ruins, they were detected by the Covenant, and SPARTAN-117 led the commandos in eliminating Covenant Shades and holding their position against waves of Covenant troops until a Pelican could drop off an [[M12 Warthog LRV]] and a pair of [[Marines]]. 

[[File:H2 IAC Hover.jpg|thumb|left|The [[UNSC In Amber Clad|UNSC ''In Amber Clad'']] hovers slightly over [[Installation 05]], preparing to release a dozen [[Human Entry Vehicle]]s to begin the UNSC offensive on Installation 05.]] 
[[File:H2 SPARTAN117 Make Noise.jpg|left|thumb|[[SPARTAN-117]] readies an [[M19 Rocket Launcher]] and a [[M7/Caseless Submachine Gun|M7 SMG]].]]
While the immediate objective for SPARTAN-117 and his Marines was to push through the Covenant-held Forerunner ruins and capture the Prophet of Regret, the overall UNSC objective for Installation 05 was to ensure that the Covenant would not activate the ring and extinguish all sentient life in the galaxy. To do this, the UNSC had to infiltrate the [[Library]], retrieve the [[Activation Index]], and safeguard it, thereby preventing the Covenant from using the Index to fire the ring.

After SPARTAN-117 and his men pushed through two Forerunner ruins, another Pelican air-dropped [[resupply canister]]s and a small number of Marines, refueling the UNSC offensive as they advanced through a ravine defended by [[Kig-yar Sniper]]s and Drones. They proceeded to another temple, this one with a hologram of the Prophet of Regret, who was sermonizing in a main Forerunner temple to prepare for the activation of the ring and the sublimation event of the "[[Great Journey]]". After learning all of the information the Prophet could provide, his elimination became the primary objective for SPARTAN-117, as his death would destabilize the Covenant politically and religiously. After [[Cortana]] deciphered the hologram, SPARTAN-117 and a pair of Marines battled through a pair of Covenant-held temples before reaching an open platform. At the time, the Covenant became aware of UNSC activity, and began becoming aggressive, so Commander Keyes sent several Pelicans towards John-117, which air-dropped more resupply canisters on the platform.

The UNSC continued attacking, proceeding from the platform to a gondola which took SPARTAN-117 and his remaining Marines to a heavily-defended Forerunner underwater temple which was guarded by [[Hunters]], [[Stealth Sangheili]], [[Sangheili Honor Guard]]s and Unggoy among other Covenant forces. After emerging from the submerged temple at a hilly Forerunner ruin, they were engaged by [[Yanme'e]], Sangheili, and Unggoy attempting to halt the UNSC advance. Soon, Phantoms arrived with additional Covenant reinforcements.

===Assassination===
[[File:MC attacks Regret.jpg|thumb|right|[[Master Chief]] kills the [[Prophet of Regret]] in the Main Temple by beating him to death.]] 
However, the Covenant were ultimately unsuccessful. The UNSC, after clearing out the last ruins, were able to secure a landing zone for a [[D77-TC Pelican Dropship|Pelican]] to air-drop resupply canisters and a team of Marines, who aided [[SPARTAN-117]] in the final push towards the main temple. The UNSC forces commandeered a gondola they found on a tower. Despite being attacked by Covenant [[Banshee]]s and [[Ranger]]s, they were able to gain access to the temple. After destroying several defense turrets, they entered the Temple as the Prophet of Regret was finishing his sermon. 

After docking, [[High Charity]] reverted from Slipspace over Installation 05, with hundreds of warships, including those of the [[Second Fleet of Homogeneous Clarity]]. Responding to a distress signal from Regret, [[Special Operations Commander]] [[Rtas 'Vadumee]] planned to storm the temple by Phantom dropships in an urgent measure to kill SPARTAN-117 and defend the Prophet leader. However, the treacherous [[Prophet of Truth]] diverted the Phantoms, deliberately allowing the [[SPARTAN-II]] to kill Regret as part of his socio-political plans for the Covenant.

A large contingent of Sangheili Honor Guards and Unggoy defended the Prophet, but SPARTAN-117 was able to board the Prophet's levitating gravity chair and beat the Prophet to death. During the fray, all the remaining Marines were presumably killed. Shortly thereafter, a Covenant Assault Carrier repositioned over the main temple, and destroyed it with its [[energy projector]], but SPARTAN-117 fell into the lake with seconds to spare and was grasped by the tentacles of the [[Gravemind]], a Flood central intelligence, and taken prisoner.

==Race for the Index==
===Introduction===
[[File:H2 Rtas Vadumee Arguing.jpg|thumb|right|[[Rtas 'Vadumee]], flanked by a pair of [[Sangheili Minor]]s, protests the [[Changing of the Guard]] before the [[Prophet of Truth]].]]
{{Quote|[[Thel 'Vadam|You]] will journey to the surface of the [[Installation 05|ring]], and retrieve this [[Sacred Icon]]. With it, [[Covenant|we]] shall fulfill our promise, and begin the [[Great Journey]].|[[Prophet of Truth]] to the [[Thel 'Vadam]]}}

After the Prophet of Regret had been murdered, with significant consequences to the Covenant, the UNSC and the Covenant both raced to reach the Library and seize the Index. The UNSC wanted to keep it safe to prevent the activation of the installation, but the Covenant desired to bring the "Sacred Icon" (the Covenant name of the Index) to the [[Control Room]] of the ring and activate the Halos.

===Changing of the Guard===
{{Main|Changing of the Guard}}

{{Quote|Recommissioning the [[Honor Guard|guard]] was a radical step, but recent events have made it abundantly clear that the Elites can no longer guarantee [[Prophet|our]] safety.|[[Prophet of Truth]] to [[Rtas 'Vadumee]]}}

After the death of Regret at the hands of the [[Demon]]. Rtas 'Vadumee was furious at the Prophet of Truth for withdrawing his men, who could have saved Regret. However, Truth deliberately and wrongfully framed the Sangheili for the death of Regret. The [[Honor Guard]]s of the Covenant were decommissioned, and the Brutes took over as the guardians of the Prophet hierarchy, a move that infuriated the Elites and drove an even deeper rift between the Jiralhanae and the Sangheili, who were already mortal enemies.

===Containment Shield===
 
[[File:H2 Containment Shield.jpg|thumb|right|[[Tartarus]]'s [[Phantom]] nears the [[Sentinel Wall]] to deploy the [[Thel 'Vadam|Arbiter]], with the [[Containment Shield]] and the [[Library]] visible in the background.]]
{{Quote|Once the [[Containment Shield|shield]] is down, we'll head straight to the Library. I do not wish to keep the [[Prophet|Hierarchs]] waiting.|[[Tartarus]] to the Arbiter}}

However, before either faction could reach the Library, it was shielded by the [[Containment Shield]] - a recognized impenetrable energy shield denying ''anyone'' access to the Library. The shield was projected by a Forerunner power generator buried within the [[Sentinel Wall]], a large underground Forerunner complex heavily defended by [[Sentinels]], [[Sentinel Majors]], and even [[Enforcers]]. Numbers of Brutes, Jackals, and Unggoy had already attempted to penetrate the Sentinel Wall, with pockets scattered all over the facility, all being overwhelmed by Sentinel defenders. However, the Arbiter was air-dropped by [[Tartarus]]'s Phantom at the periphery of the wall in the beginning phase of a Covenant offensive to deactivate the Containment Shield, enter the Library, and seize the Sacred Icon. 

After battling through the forward section of the Sentinel Wall and moving even deeper through the facility, the Arbiter was able to destroy an Enforcer, and disengage the plug locks of the generator, and then physically disengage the generator out of its "cradle", powering off the Containment Shield. While the shield had been disengaged, the path to the Library was far from clear. There was a rampant Flood infestation: the second half of the Sentinel Wall was heavily saturated with Flood, and there were icy canyons heavily entrenched by Flood battling against outnumbered Sentinel defenders that lay between the perimeter of the Containment Shield and the Library, which was accessible only by an underground gondola.

Tartarus attempted to pick up the Arbiter and head directly for the Library, but his Phantom was engaged by an Enforcer, forcing the Arbiter to battle through through the warring Flood and Sentinels that resided in the Flood-Infested Wall<ref name="guide115">'''[[The Official Halo 2 Strategy Guide]]''', ''page 115''</ref> by himself. However, the Arbiter was not alone - the UNSC had dispatched a squad of Marines to also fight through the facility, but they were overwhelmed by the Flood, leaving a trail of crumpled bodies throughout the facility and fueling the Flood's ever-growing army. The Covenant apparently sent a small team of three Special Operations Sangheili to clear out the lower levels of the complex, but these too were killed. Finally, the Arbiter jumped down a series of plummeting vertical tunnels, exiting from the Sentinel Wall and entering the battle-torn icy plains of the [[Quarantine Zone]].

===Battle of the Quarantine Zone===
[[File:Sacredicon1600.jpg|right|thumb|The [[Library]] of [[Installation 05]] situated deep inside the [[Quarantine Zone]].]] 
[[File:H2 Rtas Vadumee Rally.jpg|thumb|right|[[Rtas 'Vadumee]] valiantly rallies his [[Special Operations Sangheili]], informing them that they must advance towards the center of the [[Quarantine Zone]] and destroy the [[Flood]].]]
{{Main|Battle of the Quarantine Zone}}

The Quarantine Zone was supposed to be a location where during times of war, the Sentinel custodians of the installation could herd the Flood, and prevent them from entering the Library. Two [[Sentinel Constructor Factory]] ships<ref>'''The Official Halo 2 Strategy Guide''', ''page 122''</ref> hung in the air, deploying Sentinel reinforcements. However, the Quarantine Zone was compromised by the Flood, and the Flood managed to crash one of the floating factories, sending it plummeting down to the ringworld. 

The Covenant shortly established a "camp",<ref name="guide115"/> air-dropping seven drop pods that contained Rtas 'Vadumee and six Special Operations Sangheili, along with several plasma turrets and a [[deployable lookout tower]]. 

{{Quote|We shall cut into the heart of [[Flood|this infestation]], retrieve the [[Sacred Icon|icon]], and burn any Flood that stand in our way! Forward, warriors, and fear not pain or death!|[[Rtas 'Vadumee]]}}

The Arbiter met with three of the Elites just outside of the Sentinel Wall, and together, they defended a small hill from the Flood before pushing inwards, where the Special Operations Commander had landed and established a small outpost, complete with turrets and the gravity lift tower, where the Special Operations force held out against waves of Flood attacks from the cliffs before they were reinforced by a pair of Phantoms that dropped off a [[Spectre]] and a pair of Ghosts. The Covenant were able to use these vehicles to advance through a large indoor Forerunner facility before entering the first of a series of expansive outdoor arctic canyons. Despite the prowess of the Special Operations Sangheili and the Arbiter, the UNSC were swifter to advance through the Quarantine Zone - the ''In Amber Clad'' deployed a Pelican dropship that cruised above the battling Flood and Sentinels, cutting directly towards the Library while the Arbiter and his men were forced to fight through waves of Flood, including Flood-commandeered Ghosts, Warthogs, Wraiths, and [[Scorpions]], while all the while, Enforcers rained heavy fire. 

The small Covenant task force was forced to debark from its vehicles as they transgressed the wreckage of one of the Sentinel Constructor Factories, although just beyond the wreckage on the other side, they were met by another Covenant Phantom, this one dropping off a Spectre manned by Rtas 'Vadumee himself and another Special Operations Elite. However, as they progressed through the last series of snowy plains, they were met with increasingly heavy resistance as they neared the Library. The Sentinels were in much larger force, while a large number of Flood-infested humans savagely held a barricade against the Library, using crates, turrets, and heavy weapons to prevent anyone to gain entrance to the Library and retrieve the Index, which would eventually lead to the extermination of the Flood.

===Library===
[[File:H2 Index.jpg|thumb|right|[[Miranda Keyes]] stretches over a chasm in the [[Library]], securing the [[Index]].]]
{{Quote|More [[UNSC Marine Corps|human]]s...they must be after the [[Activation Index|icon]].|Rtas 'Vadumee to the Arbiter}} 

However, a small UNSC Marine force led by Miranda Keyes and Avery J. Johnson was able to slip through, and in the end, the Arbiter, Rtas 'Vadumee, and half a dozen Special Operations Sangheili were able to slip into the periphery of the Library. There were a pair of [[gondola]]s, that when activated, autonomously brought their passengers into the upper tiers of the Library, where the Index was kept. While the UNSC was first able to seize a gondola, the Covenant were close behind. However, when the Flood began to screech, alerting the Covenant that they were in full force in the bowels of the Library, Rtas 'Vadumee took a pair of Special Operations Elite, holding them at the entrance to the gondolas to defend the rest from the Flood as the Arbiter took four Special Operations Sangheili on the second gondola, trailing behind the UNSC-held one.

The gondola's ride, however, was harrowing. Flood entered the gondolas, jumping from the upper levels and also crawling in underneath on their undersides, assailing both the UNSC troops and also the Arbiter and his quartet of Special Operations Elites. Tartarus, in his Phantom, attempted to provide cover fire for the Arbiter, using the three plasma cannons of his dropship to burn off any Flood on the upper levels of the Arbiter's gondola, but later, Tartarus chased after the UNSC-held gondola. 

Finally, both gondolas ascended to the top levels of the Library, although the UNSC one arrived first, and a small UNSC force of six soldiers (four Marines (including [[Perez (Marine)|Perez]] and [[McKenzie]])) led by Miranda Keyes and Avery Johnson, entered. Although many Combat Forms had been exhausted in the Flood's last-ditch attempt to stave off the gondolas, there were a large number of [[Infection Forms]] prowling the Library which killed off the four UNSC Marines as Keyes and Johnson advanced towards the core of the Library. Meanwhile, the Arbiter silently snuck in behind them.

Miranda stretched over a seemingly bottomless chasm, grasping for the Index, and then barely making it, securing it on her belt. Meanwhile, Sergeant Johnson shouted for the remaining Marines to report. When there was no response, the pair of UNSC personnel cautiously began to edge away from the core, with Johnson lifting his [[BR55 Battle Rifle]] at the ready while Miranda hefted her pair of [[M7/Caseless Sub Machine Gun|SMGs]]. However, the Arbiter engaged his active camouflage, cloaking himself as he lunged at Johnson, head-butting him into unconsciousness, and as Miranda fired a spatter of bullets from her submachine guns, the Arbiter disarmed her, but before she could react, [[Tartarus]] entered with four of his [[Brute Captain]]s. Tartarus used his [[Gravity Hammer]], the [[Fist of Rukt]], to stun Miranda and gravitationally levitate her towards him, draping her over his shoulder and then clasping the Index and securing it for himself.

With the Library clear and devoid of hostiles, the Arbiter demanded to have the Index, as he was personally ordered by the Prophet of Truth to secure it for the Covenant. However, unbeknownst to him, he had been betrayed by the Prophets, as had the entire Sangheili race. The Prophets had made the Brutes their champions, casting aside the physically inferior Elites. 

Tartarus refused to give the Sacred Icon to the Arbiter, and instead, his Brute Captains leveled their [[Brute Shots]] at the Arbiter as Tartarus revealed the betrayal. The Arbiter jerked his neck up in horror as Tartarus swung his Gravity Hammer, sending a gravitic shock that sent the Arbiter into the bottomless chasm above which the Index was once situated.

This event turned out to be a disaster for UNSC forces at the Library. Not only were most of the marines slaughtered by the Flood and Tartarus, they lost a lot of vehicles and equipment to the Flood but the worst part was In Amber Clad falling into the Flood's hands, enabling them to capture High Charity later. 

{{Quote|The release of [[Flood|the parasite]] was unexpected, unfortunate. But, there is no need to panic. In truth, this is a time to rejoice. A moment that all the [[Covenant]] should savor...for the [[Sacred Icon]] has been found. With it, our path is clear, our entry into the Divine Beyond guaranteed! The [[Great Journey]] is nigh...and nothing, not even the Flood, can stop it!|[[Prophet of Truth]]}}

Meanwhile, Tartarus brought the Sacred Icon to ''[[High Charity]]'', where the Prophet of Truth exulted him and encouraged the Covenant to celebrate, for the Sacred Icon was secure, and that soon afterward, that the Halos would be fired and the Great Journey would be brought upon the Covenant.

==Covenant Civil War==
===Introduction===
[[File:Truth with Index.jpg|thumb|right|The [[Prophet of Truth]] triumphantly announces to the Covenant that the [[Sacred Icon]] has been found and that there is no need to worry.]]
{{Quote|There is still time to stop the key from turning, but first it must be found. [[SPARTAN-117|You]] will search one likely spot, and you will search another. Fate had us meet as foes, but this ring will make us brothers.|[[Gravemind]] to [[SPARTAN-117]] and The Arbiter}}

However, the Covenant would not activate the Halos unimpeded. The Flood, who would be starved if the rings were activated, would soon attack the Covenant to prevent the activation, and the UNSC, who understood that all sentient life would be erased, also opposed the Covenant. Later, after the fragmentation of the Covenant into the [[Covenant Loyalists]] and the [[Covenant Separatists]], the Separatists would understand the true intent of Halo and attack the Loyalists to prevent them from activating the ringworld.

Meanwhile, SPARTAN-117, who had fell into the lake, and the Arbiter, who had been thrust into the chasm of the Library, were both caught by plant-like tentacles and grabbed into the lower reaches of Installation 05, where they met face-to-face the Flood central sentient intelligence known as the "[[Gravemind]]", along with the [[Prophet of Regret]] and [[2401 Penitent Tangent]], the monitor of Installation 05. The Gravemind than explained to the Arbiter why the Halos must not be activated for the interests of galactic life. The Gravemind, holding both SPARTAN-117 and the Arbiter prisoner, explained that in his plan to prevent the activation of Installation 05 by the Covenant, he would manipulate Halo's teleportation grid, sending SPARTAN-117 to ''High Charity'' to search one likely spot where the Index was placed, and sending the Arbiter to the cliffs just beyond the Control Room, another likely spot.

===Battle of High Charity===
[[File:High Charity wallpaper.jpg|right|thumb|''[[High Charity]]'' surrounded by hundreds of Covenant warships, with three [[Phantom]]s clearly prominent in the foreground.]] 
[[File:H2 Grunt Dissension.jpg|right|thumb|In mounting social pressures, the [[Grunt]]s and [[Jackal]]s become disillusioned about the cause of the [[Covenant]] before open warfare explodes.]] 
[[File:H2 High Charity Orbital Battle.jpg|thumb|right|As the Loyalists and Separatists war for control of ''High Charity'', Jiralhanae-controlled and Sangheili-controlled warships open fire at each other over the planetoid.]]
{{Main|First Battle of High Charity}}

SPARTAN-117 was teleported by the Gravemind directly into the High Council Chamber of ''High Charity'', where the Prophets of Truth and Mercy addressed the Covenant that the Sacred Icon was secure. Before SPARTAN-117 could kill both Prophets, they escaped by means of an elevator, while the doors were locked and waves of [[Honor Guard Brute]]s, Minor Jiralhanae, and Unggoy entered in an attempt to kill the supersoldier. [[Cortana]] managed to unlock the doors, and SPARTAN-117 chased through two towers and a set of corridors in pursuit of Truth before Cortana picked up the IFF transponder signals of UNSC Marines - prisoners of the Covenant being kept in two brigs in a multitiered detention block.

Cortana managed to reverse a central gravity lift, allowing SPARTAN-117 to enter the detention block. However, Tartarus had anticipated this, increasing security around the brigs while a massive firefight ensued as SPARTAN-117 released five Marines from two brigs, who assisted SPARTAN-117 in his pursuit of Truth to kill him and secure the Index.

{{Quote|The Elites have failed to protect the [[Prophet]]s, and in doing so, have put all our lives at risk. Let no warrior forget his oath, 'Thou, in faith, shall keep us safe, whilst we find the Path'. With my blessing, the Brutes now lead our fleets! They ask for your allegiance, and you shall give it.|[[Prophet of Truth]]}}

However, meanwhile, the Covenant splintered in minutes after SPARTAN-117 emancipated the captive Marines. The Prophet of Truth made an epic announcement, and in three sentences over the loudspeakers of ''High Charity'', put his plan to betray the Elites into action: he ordered all of the Covenant to follow the Brutes as their military commanders, and inevitably, the Sangheili, seething in hatred against the Brutes, took this as their final straw. Slighted by the Prophets, the Sangheili burst into full-out warfare on ''High Charity'' and across the rest of the Covenant empire against the Jiralhanae. While the Unggoy and Hunters followed the Sangheili, the Kig-yar and the Yanme'e supported the Prophet-blessed Brutes. Warship crewmen began to open fire upon each other with small arms, and the Covenant fleets began to open fire against each other.

Truth's transmissions, however, allowed Cortana to triangulate his position, allowing her to direct SPARTAN-117 and his Marines in their hunt for the Prophet. The Covenant attempted to stop Cortana, but were unable to prevent her.

As SPARTAN-117 and the Marines reached the [[Hanging Gardens A]], the first scene of Covenant fratricide was seen, as Sangheili Honor Guards, Sangheili Minors, Mgalekgolo, and Unggoy fought against Jiralhanae and Kig-yar Snipers amongst the massive plants. SPARTAN-117 and his men advanced to the Mid-Tower, where Rangers and Special Operations Elites entered the fray, and the Brutes unleashed their Drones into the combat.

Even as the imprisoned Marines were freed, the crew of the ''In Amber Clad'' were in peril. At the same time the Gravemind had sent SPARTAN-117 to hunt for the Index in the bowels of ''High Charity'', the Flood boarded ''In Amber Clad'' (probably via captured Pelicans), killed or infested the crew, and took control of the ship.  The infested-''In Amber Clad'' was then jumped directly over ''High Charity'', where it plummeted uncontrollably, crashing into the Far Tower.<ref>'''The Official Halo 2 Strategy Guide''', ''page 128''</ref>

[[File:H2 IAC Crashed.jpg|thumb|right|The [[UNSC Frigate]] [[UNSC In Amber Clad|UNSC ''In Amber Clad'']] crashed into a Covenant tower as part of the [[Flood]]'s plot to infest ''[[High Charity]]''.]] 
[[File:H2 Phantom Departure.jpg|thumb|right|The three [[Phantom]]s of [[Tartarus]] and the [[Prophet of Truth]] just before [[SPARTAN-117]] arrives.]] 
[[File:H2 Phantom Depature2.jpg|thumb|right|Of the three Phantoms, two head for [[Installation 05]], while Truth departs for the [[Forerunner Ship]].]] 
[[File:H2 Flood Touchdown.jpg|thumb|right|The [[Flood]] descend upon Loyalist-controlled ''High Charity'', touching down in the [[UNSC In Amber Clad|UNSC ''In Amber Clad'']]'s [[D77-TC Pelican Dropship|Pelican]] dropships.]] 
[[File:H2 Forerunner Ship Takeoff.jpg|thumb|right|[[Cortana]] watches the [[Forerunner Ship]] lift off from ''[[High Charity]]'' for [[Earth]], with both the [[Prophet of Truth]] and [[SPARTAN-117]] aboard.]]
{{Quote|Once the towers are clear, we'll drive [[Covenant Separatists|them]] from the lower districts!|[[Tartarus]]}}

However, by the time that the small UNSC squad entered [[Hanging Gardens B]], Covenant Separatist resistance on ''High Charity'' had broken. In the second Hanging Gardens, the Covenant Separatists fell back, leaving behind large numbers of [[Stationary Shield Generator]]s, abandoning numbers of Unggoy to berserk Jiralhanae as the Sangheili fell back to the Far Tower and the [[Mausoleum of the Arbiter]], drawing a last line of defense there. In the forward sections of the Far Tower, the Separatists held a choke-point bridge with a pair of plasma turrets, Special Operations Elites, and a pair of Hunter warriors. In the Mausoleum of the Arbiter, Specialist [[Sangheili Ultra]]s and Mgalekgolo fought against waves of attacking Jiralahane. Despite their efforts, the Prophets of Truth and Mercy, Tartarus, and a handful of Brute Captains were able to tunnel through the last Separatist defenses to the far docking bays of the Far Tower.<ref>'''The Official Halo 2 Strategy Guide''', ''page 129''</ref> SPARTAN-117 pursued Tartarus, fighting through the Far Tower and the Mausoleum of the Arbiter to make it through to the Phantom pads.

{{Quote|[[Prophet of Truth|Your pal]]. Where's he going?|[[SPARTAN-117]]}}
{{Quote|[[Earth]]...to finish what [[Prophet|we]] started. And this time, none of you... will be left behind...|[[Prophet of Mercy]]'s last words}}

The SPARTAN was too late, however. The Prophet of Truth ordered Tartarus to use the Sacred Icon in the Control Room of Installation 05, and activate the Halos. Tartarus took a detachment of Brute Honor Guards along with him in two Phantoms, along with UNSC prisoners Avery Johnson and Miranda Keyes. Truth and Mercy took a third Phantom to the [[Forerunner Ship]] - the central energy source of ''High Charity'', and also a fully functional starship that the two remaining High Prophets were going to use to reach Earth, and "finish what The Prophets started". 

Meanwhile, the Flood were escaping from the crashed hulk of the ''In Amber Clad''. They seeped out of the rents in its hull armor, and also exhibited unexpected intelligence, commandeering its Pelican dropships and sending them over the surface of ''High Charity'', crashing into the floors and releasing [[Combat Forms]], and spilling Infection Forms out of the air from opened hatches. The Prophet of Mercy was beset by an Infection Form and died before he could reach his Phantom. However, Tartarus and Truth were able to depart before SPARTAN-117 could arrive.

Despite the fact that SPARTAN-117 had failed to capture the Prophet of Truth before he could depart in his Phantom for the Forerunner Ship, it was still imperative that the SPARTAN chase after him and kill him, as if he marshaled the Covenant fleets to Earth to finish whatever he planned, the already besieged Earth would inevitably fall, despite the UNSC's best efforts. Just then, a Pelican crashes on the balcony, and some familiar [[Flood Combat Form|creatures]] run out of the ship.

By that time, Covenant Separatist resistance had completely shattered on ''High Charity''. There were none to little Elites nor Hunters remaining, and only several scattered Unggoy. The Loyalists, however, retained a large number of Brutes, Jackals, and Drones. Despite the lack of a Separatist ground force, they were still very much present in space, where the Covenant fleets over ''High Charity'' had splintered in allegiances, with Sangheili and Jiralhanae ships actively engaging and destroying each other.<ref>'''[[Halo 2]]''', campaign level, ''[[High Charity (level)|High Charity]]''</ref>

While Truth was taking a Phantom to the Forerunner Ship, Cortana detected an energy conduit to the ship located in the Mausoleum Tower ahead of SPARTAN-117's position. However, ''High Charity'' had become horribly twisted within minutes: an insidious Flood presence spread surprisingly quickly through the planetoid, disrupting power, creating a dark, gloomy atmosphere, spreading Flood spores into the air, covering large parts of ''High Charity'' in Flood biomass, and sending Flood forms all across the city-space, where the Flood fought to take ''High Charity'' from the remaining Covenant Loyalist forces. 

SPARTAN-117 entered the Mausoleum Tower from the Phantom landing pads, battling through unlit, tight corridor ways where numerous Flood combat forms engaged outnumbered Brutes and Jackals, and strange Flood biological growths began to sediment against the walls. Meanwhile, the Prophet of Truth sent broadcasts throughout the city, urging the remaining Loyalists that the Covenant would prevail against the Flood while the Gravemind manipulated the loudspeakers, proclaiming that the Flood would infest ''High Charity'' and send the Covenant to their graves. SPARTAN-117 cut across the massive interior of the Mausoleum Tower, moving to the north face of the tower and making his way along a peripheral convoluted corridor to the eastern end of the tower, where he took a Gravity Lift to access the Inner Sanctum: the personal quarters of the Hierarchs.

There, a line of Honor Guard Brutes and Jackals had made a final stand against the Flood upon the gold-rimmed doors that sealed access to the Inner Sanctum. However, large amounts of Flood began to attack, and SPARTAN-117 was forced to destroy all the Covenant and Flood before entering the Inner Sanctum, and taking an adjacent Gravity Lift to a large outdoor room that hosted the viridian energy conduit to the Forerunner Ship. SPARTAN-117 was able to jump in the conduit just in time, barely making it to the ship before it lifted off for Earth. However, Cortana stayed behind: while SPARTAN-117 would attempt to neutralize the ship before it rallied the Covenant fleets at Earth, there was another danger: Tartarus still had the Index, and was about to activate Installation 05 shortly. In the event that he was about to trigger the Halos, Cortana announced that she would detonate the fusion reactors of the ''In Amber Clad'', just like she had done to the [[UNSC Pillar of Autumn|UNSC ''Pillar of Autumn'']] at [[Installation 04]], and the blast would destabilize the ring and prevent the activation of the Halos.

Shortly afterward, all Covenant resistance on ''High Charity'' broke and succumbed to the Flood, who had infested surprisingly large amounts of the planetoid even during the raging combat between the Covenant and the Flood. Cortana, who resided in ''High Charity'''s computer systems to be ready to detonate the frigate's reactors as a final failsafe, was captured by the Gravemind, although her eventual fate, and that of the Gravemind and ''High Charity'', is unknown, thus concluding the Battle of ''High Charity''.

===Uprising===
[[File:SpecOpsElite3.jpg|thumb|right|A [[Special Operations Elite]] that survived the initial Brute betrayal draws an [[Energy Sword]] to aid the Arbiter in avenging the fallen Elites slain by the Brutes.]] 
[[File:H2 Arbiter and Rtas.jpg|thumb|right|[[Thel 'Vadamee]] and [[Rtas 'Vadumee]] confirm the disloyalty of the Brutes and discuss a plan to break into the [[Control Room]] and secure the [[Sacred Icon]] from [[Tartarus]].]]

The Covenant politico-military fractures were not restricted to ''High Charity'': they extended to military units across the Covenant, including those on the surface of Installation 05. Upon Truth's order that the Brutes were now the ruling caste of the Covenant, Tartarus ordered the execution of the [[Elite Councilor]]s, who had been gathered in the Control Room of Installation 05 for the consecration of the Sacred Icon before the Halos were fired. While most of the Councilors were murdered in cold blood, a small number were taken prisoner by the Brutes. The rest of the Covenant garrison, however, was not so fortunate. A [[CCS-class Battlecruiser|''CCS''-class Battlecruiser]] hovering close to the Control Room was taken by the Jiralhanae from the Sangheili, and a large number of Sangheili Minors and Unggoy stationed in the cliffs above the Control Room were killed. However, there was still a number of Unggoy that managed to resist, although they were terrified by the murders of their Elite superiors and Unggoy comrades.

However, the Sangheili were quick to strike back. The Gravemind teleported the Arbiter to a high cliff south of the Control Room, and gave him an objective: to prevent Tartarus from using the Sacred Icon and activating Halo, which would not result in the promised sublimation event of the Prophets, but only death and destruction on a galactic scale. The Arbiter arrived just too late, witnessing the murders of a handful of Elites from afar at the hands of the Brutes, but was able to push forward against a number of patrolling Brutes, and meet up with a number of surviving Sangheili warriors.

The small group of survivors, led by the Arbiter, pushed northward through a large Brute-held Forerunner structure, unpinning small groups of scattered loyal Unggoy and killing dozens of Brutes, Jackals, and Drones. Afterward, they emerged from the structure, and fought their way past several Brute camps, commandeering some Ghosts along the way. As they neared another cluster of structures, they encountered heavier resistance in the form of Brute-controlled Wraiths.  The Arbiter and his Sangheili managed to defeat the Brutes and secure a landing zone, allowing for additional Sangheili reinforcements to arrive.

After securing the first half of the camp, the Arbiter and whatever surviving allies moved into the weapons cache, where the Brutes had aggregated a large number of Covenant and UNSC weapons alike, demonstrating their religious heresy in their indifference towards collecting UNSC armaments.  The Arbiter led his group outside the structure and into a tunnel.  After defeating the Brutes inside, the Arbiter exited the tunnel and found himself facing a Wraith tank.  To his surprise (and relief), the pilot was revealed to be Rtas 'Vadumee.

===Assault on the Bastion of the Brutes===
Rtas 'Vadumee informed the Arbiter that Tartarus was within the Control Room, and would soon be activating the Halos. However, the doors to the Control Room were nearly completely impenetrable, and would only be opened by the firing of the main cannon of a [[Scarab]] walker.  Fortunately, a Scarab was available at the Bastion of the Brutes.

While Rtas 'Vadumee advanced forward in a Wraith tank, the Arbiter and another Special Operations Sangheili took a Spectre, and together, the Elites battled through a swarm of Ghosts, several Wraiths, and a bombarding Phantom, narrowly clearing out the extensive Brute defenses on the exterior of their base and securing entrance into the Bastion of the Brutes, where the Arbiter found another Special Operations Sangheili and a pair of Mgalekgolo, all of whom were loyal to the Separatist cause. Meanwhile, Rtas 'Vadumee said that he would briefly watch the Arbiter's back, and would prevent any Brute reinforcements from entering in behind them while they cleared out the stronghold. Later, he announced that he would retake the battlecruiser that was hanging in the distance. 

The Arbiter and his band of Sangheili and Hunters stormed the Bastion, fighting their way past Brutes, Jackals, Drones, and even a Phantom. Eventually, they came across a two-tiered Brute-held prison where a pair of Hunters and a pair of Councilor Elites were being held. The Arbiter freed them by destroying the forcefield generators, and with their help, slew the Brute guards.  The Separatist force then exited the Bastion and stepped onto the platform where the Scarab was docked. Much to their surprise, they discovered the presence of humans who were being held prisoner by the Brutes.  Amongst the prisoners was Sergeant Johnson.  The Brutes had just received orders from Tartarus to execute the prisoners, when the Arbiter and his followers attacked.  The humans took advantage of this distraction to free themselves and take control of the Scarab.   

After all the Brutes on the platform were dead, there was a brief standoff between the Separatists and the UNSC personnel. However, both the Arbiter and Sergeant Johnson realized that they shared a common enemy and objective. The two sides begrudgingly joined forces and set out to stop Tartarus from activating Halo.

===Control Room===
 
[[File:Control Room3.jpg|right|thumb|A vista of the [[Control Room]] of [[Installation 05]], an area of hot contestation shortly before the conclusion of the Battle of Installation 05.]] 
[[File:H2 Scarab Threatening.jpg|thumb|right||[[Avery J. Johnson]] directs the main cannon of his newly-commandeered [[Scarab]] walker at the Arbiter.]] 
[[File:Sargescarab.jpg|thumb|right|[[Avery J. Johnson]] strikes a deal with the Arbiter in the interests of sentient life across the galaxy.]]

The Arbiter took possession of a friendly Banshee and provided cover fire for Johnson's Scarab. Together, they fought their way past a large Brute force consisting of multiple Wraiths, Banshees, Spectres, and also Shade turrets. Finally they reached the control room.  Johnson fired the Scarab's main gun three times, destroying the doors to the control room and allowing the Arbiter to land and enter the chamber.

Inside the chamber, the Arbiter fought his way through one room with large numbers of Brute Captains and Brutes Honor Guards who had been ordered to prevent the Arbiter from disturbing Tartarus while he activated the Halos, or his "Holy Work". The Brutes appeared to be of increasing desperation, even commonly wielding UNSC-manufactured M90 shotguns, usually held as trophies. Despite reinforcements, the highly-ranked Brutes were unable to hold the room, and the Arbiter continued down an arched corridor before confronting Tartarus in the control room.  Inside, he found Tartarus and his Brutes, along with two prisoners - Miranda Keyes and the Oracle, 343 Guilty Spark. 

Tartarus had been trying to force Miranda Keyes to insert the Sacred Icon into its place, as only a [[Reclaimer]] could activate Halo. The Arbiter entered the control room, surprising Tartarus, and told the Chieftain to stand down. Tartarus refused, and his Brutes were about to attack the Arbiter, when Johnson suddenly appeared, pointing a [[Particle Beam Rifle]] at Tartarus' head.  Seeing that he was in danger, Tartarus ordered his Brutes to hold back for the moment.  

Hoping to make Tartarus understand the truth about the Rings, Arbiter asked 343 Guilty Spark what Halo's true purpose was.  The Monitor explained that the Rings were weapons of mass destruction, built by the Forerunners as a last resort means to stop the Flood.  When asked about what happened to the Forerunners, Guilty Spark revealed that the Forerunners ultimately chose to activate the Rings, destroying themselves and all other sentient life in the galaxy, thereby depriving the Flood of its food.  With the Great Journey now revealed to be a lie, the Arbiter once again tried to get Tartarus to stand down.  Despite Guilty Spark's revelations, however, Tartarus, blinded by his loyalty to the Prophets and his hatred for Sangheili, refused to listen.  The Chieftain threw the Monitor at Johnson, knocking him out for a moment.  He then physically forced the Sacred Icon into Miranda Keyes' hand and shoved it into the receptacle, beginning the activation of Installation 05. Behind their platform, a massive Forerunner multitiered construct began to open up: a three-storied structure, which at its center, boasted a brilliant gravity column which was charging the ring to fire.

Miranda jumped out of the way of the imminent firefight as the Arbiter, the conscious Johnson, and a small cluster of recently-arrived Zealots and Councilors, charged at Tartarus and his guard of four Brute Captains.  The Brute guards were quickly slain, and Tartarus retreated onto the three-level structure at the center of the control room. When the Arbiter and his allied Zealots and Councilors pursued, they found to their dismay that Tartarus was protected by a nearly impenetrable energy shield.  Only Sergeant Johnson, with his Particle Beam Rifle, could disable Tartarus' shields, and only for a few seconds.

Meanwhile, Miranda Keyes argued with Guilty Spark and eventually forced him to reveal that the firing sequence could be stopped if the Reclaimer simply removed the Index from the its position.  However, she could not do anything while Tartarus was still alive. The Arbiter and his Elites battled Tartarus, who used his massive Gravity Hammer, the Fist of Rukt, to slay many high ranking Elites. The Arbiter, however, used his skill and cunning to evade the Brute's attacks, striking back only when Johnson had lowered Tartarus' shields. In the end, after a long, protracted fight, the Arbiter landing a finishing blow on Tartarus while his shields were downed, killing the Chieftain of the Brutes. 

Miranda Keyes immediately leapt to action after Tartarus died, snatching the Index from the control panel. Despite the fact that Installation 05 was primed to fire, because of Miranda's quick actions, the removal of the Index only triggered a partial firing, one that was inconsequential and led to the loss of no life whatsoever. However, 343 Guilty Spark informed them that because of the partial activation of Installation 05, the other five remaining installations were set onto standby mode, and were ready to fire upon command from a central Forerunner installation: [[Installation 00|the Ark]].

===Orbital battle===
While ground battles raged over the contested lands of ''High Charity'' and Installation 05, the Covenant fleets, divided, had not been idle or inoperative. During the hours which the Loyalists and the Separatists warred for the districts of ''High Charity'', the Covenant fleet had splintered within itself, and its warships were destroying each other systematically over the planetoid as Brute-controlled warships raged against Sangheili-controlled ones. However, after the Prophet of Truth's departure in the Forerunner Dreadnought, the fighting cooled as many ships fell silent, wondering what loyalties to assume in light of Truth's sudden abandonment and Tartarus' death, although a small number of starships continued fighting.

Despite the isolated Separatist ground victory on Installation 05, there was a much greater threat: the Flood. Having assumed dominance over the whole of ''High Charity'' and certain locations on Installation 05, they tried boldly expanding into space, attempting to take over Covenant warships. The ambitious [[Sangheili Major]] [[Voro 'Mantakree]] assumed command of the [[Reverence-class Cruiser|''Reverence''-class Cruiser]] ''[[Incorruptible]]'', and audaciously sent a fleetwide dispatch to the idling Covenant fleet amassed over ''High Charity'': the Flood were lifting off from Installation 05 in [[DX-class dropship|''DX''-class "Spirit" dropships]] and Banshees and were attempting to attack and take control of Covenant warships to spread throughout the galaxy. Surprisingly, even divided political opinions were united after the transmission, and four [[Covenant Destroyer]]s, including the ''[[Rapturous Arc]]'', that were about to be consumed by the Flood were burned and destroyed to prevent the parasite from capturing the warships.

Shortly afterward, however, the fleets splintered without a common foe. The [[Alpha Jiralhanae]] [[Gargantum]] attempted to coordinate a Loyalist uprising against the Sangheili, and chased with four [[Covenant Frigate]]s after 'Mantakree. Using deft tactics and maneuvering out the Separatist carrier ''[[Lawgiver]]'', the ''Incorruptible'' destroyed the Brute-controlled frigate ''[[Tenebrous]]'', although the three remaining frigates, including Gargantum's personal frigate, the ''[[Twilight Compunction]]'', continued pursuing him. Soon afterward, the entire Covenant fleet began turning on itself, following Gargantum's example<ref>'''[[Halo: Ghosts of Onyx]]''', ''page 199''</ref>. The UNSC ''Dusk'', one of the five UNSC ships originally sent to tail Regret's Assault Carrier, witnessed the massive encounter as Covenant ships turned upon one another and destroyed themselves in a civil war. 

However, the ''Incorruptible'' did not continue in the orbital battle, as a revered Sangheili fleet commander, [[Imperial Admiral]] [[Xytan 'Jar Wattinree]], urged all Elites to regroup over the outpost world [[Joyous Exaltation]] of the [[Salia System]]. 'Mantakree obediently left the battle, entering Slipspace towards Joyous Exaltation. During the pursuit, UNSC SPARTAN-II [[Blue Team]] dropped in the midst of the chase as the ''Incorruptible'' prepared to leave the system, in their captured Covenant Destroyer, the ''[[Bloodied Spirit]]''. Gargantum was incensed that heretic Demons had seized a Covenant warship, and diverted one of the three pursuit frigates from the ''Incorruptible'' to the ''Bloodied Spirit''. The frigate managed to lower the UNSC-controlled destroyer's shields before the SPARTANs jumped to Slipspace for the [[Zeta Doradus System]].

It is heavily implied in [[Halo 3]], that the Covenant Separatists defeated the Brute Fleet and subsequently held High Charity in quarantine. However, this largely failed, due to the Gravemind sending [[Flood ship|a single ship, controlled by the Flood]], to Earth, in the hopes of infecting it and weakening the Sangheili ships in orbit around the Flood Hive. This was successful and the Gravemind was able to leave Installation 05's space and find the Ark.

==Conclusion==
[[File:H2 343GS Explains Ark.jpg|thumb|right|[[343 Guilty Spark (Monitor)|343 Guilty Spark]] informs the Arbiter, [[Avery J. Johnson]], and [[Miranda Keyes]] about the [[Ark]] and [[Installation 05]]'s unexpected shutdown.]] 
[[File:H2 High Charity Infested.jpg|thumb|right|''[[High Charity]]'' infested by the [[Flood]], becoming the newest lair for the [[Gravemind]].]] 
[[File:H2 IAC Crashed Closeup.jpg|thumb|right|The [[UNSC Frigate]] [[UNSC In Amber Clad|UNSC ''In Amber Clad'']] permanently lost, captured by the [[Flood]] and crashed into the surface of ''[[High Charity]]''.]] 
[[File:H2 Cortana Betrays.jpg|thumb|right|[[Cortana]] believed to be making an unholy alliance with the [[Gravemind]] as she is captured.]] 
[[File:H2 Forerunner Ship Reverts.jpg|thumb|right|The [[Forerunner Dreadnought]] transitions from [[Slipspace]] over [[Earth]].]] 
[[File:Battle_of_Earth_Main.jpg|thumb|right|The Forerunner Ship approaching a besieged Earth as the [[UNSC Home Fleet]] continues to fight against Covenant fleets.]]
The Battle of Installation 05 was an extremely costly battle with significant political-military consequences for the Covenant and remarkable ramifications for all sentient life in the galaxy. Hundreds or thousands of Covenant forces were slain in SPARTAN-117's quest to kill the Prophet of Regret, the race to acquire the Index from the Control Room, and the remarkable ground and orbital battles that took place on Installation 05, ''High Charity'', and the Covenant fleets hovering above the planetoid because of the [[Covenant Civil War]]. The Covenant was fractured, with the Elites rallying the Covenant Separatists against the Prophet-supported Jiralhanae, who controlled the Covenant Loyalists against the Sangheili and their allies.

The Covenant ruling system was destabilized, with the death of the Prophet of Regret on Installation 05 at the hands of SPARTAN-117 and the death of the Prophet of Mercy on ''High Charity'' at the hands of the Flood. The Prophet of Truth held the ultimate power now, with several Minor Prophets, completely re-shifting the political dynamics of the Covenant. The Brutes now held reign over the majority of the Covenant military, bringing their innate tenaciousness and ferocity to the front lines quite unlike the Sangheili had ever done. The Jiralhanae also assumed more lower-level Covenant military authority, now replacing the Sangheili as the leaders of field squads and teams. The Brutes also introduced a unique set of bloodthirsty weaponry into the Covenant's field arsenals. The Covenant fleet was believed to lose quite a bit of its technical proficiency without the innate technical knowledge of the Elites.<ref>'''[[Halo: Ghosts of Onyx]]''', ''page 194''</ref>

Sentinel defenses were completely trampled over, particularly in the Quarantine Zone, where within hours, the Flood had managed to infiltrate the well-defended Sentinel Wall and seize control of large tracts of the Quarantine Zone, even grounding an airborne Sentinel Constructor Factory ship. The Flood also permeated the Library and the surrounding grounds, eliminating almost all Sentinels from the skies, leaving only scattered Enforcers to do battle with them. The Flood also controlled UNSC and Covenant vehicles alike, reinforcing their considerable ranks with M808B Scorpion Tanks, M12 Warthog LRVs, Wraith tanks, and Ghost vehicles. Flood losses were remarkably high because of the Arbiter's actions in the Quarantine Zone and SPARTAN-117's actions on ''High Charity''. However, it was inconsequential: the Flood managed to terraform and transform ''High Charity'' into another of their "wretched hives", scoring a notable victory on ''High Charity'', capturing the Covenant's mobile home planetoid.

UNSC losses were remarkably lower because of the small number of forces they brought into the theater of operations, almost solely the crew and soldiers of the UNSC ''In Amber Clad''. Hundreds of Marines and Orbital Drop Shock Troopers, however, were lost in UNSC ground operations: the assassination of Regret and the storming on the Quarantine Zone, and a large number were infected by the Flood and made continual appearances as combat forms in the Sentinel Wall, Quarantine Zone, and Flood-infested ''High Charity''. The crewmen of the ''In Amber Clad'' were presumably killed and reanimated by the Flood as well, bringing UNSC casualty rates possibly into the thousands, although the UNSC suffered by far the least casualties amongst the four warring factions in the Battle of Installation 05.

{{Quote|[[SPARTAN-117|Master Chief]]? Mind telling me what you're doing on [[Forerunner Dreadnought|that ship]]?|[[Fleet Admiral]] [[Hood]]}}
{{Quote|Sir. Finishing this fight.|SPARTAN-117}}

In the end, the fates of the Covenant fleets over ''High Charity'' is unknown, although at least one Covenant vessel, the ''Incorruptible'', escaped. 'Matrankee was commended for his actions against the Flood on Installation 05, and was promoted to [[Fleet Master]]. The Flood continued to attempt to escape ''High Charity'' in Covenant starships, and a Covenant Separatist fleet led by [[Rtas 'Vadum]] on the ''[[Shadow of Intent]]'' held the line against the Flood. However, the Flood managed to infest at least one Elite-controlled ship, a [[CCS-class Battlecruiser|''CCS''-class Battlecruiser]], and made a [[Slipspace]] jump to [[Earth]] to attempt to infest the human homeworld. The Elite fleet in orbit over ''High Charity'' followed the Flood-controlled cruiser, and when the Flood ship crash-landed on Earth, Rtas 'Vadum and his forces aided the [[UNSC Home Fleet]] in destroying the Flood vessel and terminating the Flood spread across the planet. However, prior to this, ''[[High Charity]]'' had already left its orbit around Installation 05, and according to a scrambled distress signal from [[Cortana]], was already on its way to Earth to enter the [[Portal]].<ref>'''[[Halo 3]]''', campaign level, ''[[Floodgate (Level)]]''</ref> It was indicated though that all of the other Flood controlled ships were destroyed though: upon landing on Earth an Elite informed the Arbiter that the Elite's fleet had taken care of all of the Flood controlled ships, except for that one which had managed to break through and jump to Earth. It can be inferred that the Flood controlled ships were ultimately all destroyed except the one that jumped to Earth and High Charity which was later destroyed by the Master Chief in the [[Battle of Installation 00]]. [[Cortana]] was left to the clutches of the Gravemind. It was later shown that she answered a few questions to buy herself some time and used the opportunity to help find a way to destroy the Flood. She would later be rescued by the Master Chief who would then destroy High Charity during the [[Raid on High Charity]].

[[SPARTAN-117]] was aboard Truth's Forerunner Dreadnought, which managed to reach Earth unharmed and landed in Africa, near the Portal to the Ark, about two weeks after its departure from ''High Charity''.<ref>'''[[Halo 3]]''', campaign level, ''[[Tsavo Highway (Level)]]''</ref> The UNSC ''Dusk'' eventually withdrew to rendezvous with [[Battlegroup Stalingrad]] shortly outside of the Onyx System, and the UNSC ''In Amber Clad'' remained crashed into one of the towers of ''High Charity''.

In many ways, the battle was the true turning point in the war and in the long term would break the back of the Covenant. The Elites eventually allied themselves with the humans bolstering their fleets and taking the military strategy mind away from the Covenant.

==Gallery==
<gallery widths="160">
File:Hevstohalo05.jpg|[[SPARTAN-117]] and five [[Orbital Drop Shock Trooper]]s insert into the atmosphere of Installation 05 in [[Human Entry Vehicle]]s.
File:H2 Hard Drop.jpg|Covenant ground-based [[Shielded Plasma Turret|plasma turret]]s open fire on the inbound Human Entry Vehicles.
File:H2 Regret Holy Wind.jpg|[[Cortana]] and [[SPARTAN-117]] learn that the [[Prophet of Regret]] plans to activate [[Installation 05]].
File:H2 Miranda Index.jpg|[[Commander]] [[Miranda Keyes]] coordinates a plan with [[Cortana]] and [[SPARTAN-117]] regarding an assault plan to take the [[Index]] from the [[Library]].
File:H2 Sacred Icon Revealed.jpg|[[343 Guilty Spark (Monitor)|343 Guilty Spark]] projects an image of the "[[Sacred Icon]]" to the [[Prophet of Truth]] on ''[[High Charity]]''.
File:H2 Main Temple Vaporized.jpg|A Covenant [[Assault Carrier]] repositions over the Main Temple, destroying it with its energy projector in attempt to finish off [[SPARTAN-117]], who narrowly escapes.
File:H2 Phantom Delta Halo Descent.jpg|Tartarus's [[Phantom]] descends from '[[High Charity]]'' towards the surface of [[Installation 05]].
File:H2 Arbiter Ready.jpg|The Arbiter readies himself before the insertion.
File:Enforcer.jpg|The Arbiter fights against a [[Forerunner]] [[Enforcer]] shortly before it is diverted by [[Tartarus]]'s [[Phantom]].
File:H2 Arbiter and Rtas QuarantineZone.jpg|The Arbiter tells [[Rtas 'Vadumee]] that he needs to find the Sacred Icon at the heart of the [[Quarantine Zone]], in the [[Library]].
File:H2 UNSC Gondola.jpg|The UNSC-controlled gondola takes off for the [[Library]] first, crewed by [[Miranda Keyes]] and a small number of [[Marine]]s, including [[Avery J. Johnson]].
File:H2 Gondola Race.jpg|The two gondolas, Covenant-controlled and UNSC-controlled, race to reach the top floors of the [[Library]].
File:H2 Arbiter Gondola Phantom.jpg|Tartarus's Phantom hovers over the Arbiter's gondola, defending him from the [[Flood]].
File:H2 Arbiter Disarming Johnson.jpg|The Arbiter grabs Avery J. Johnson by his shoulders before knocking him unconscious.
File:H2 Tartarus Betrays Arbiter.jpg|Tartarus betrays the Arbiter, slamming him with the [[Fist of Rukt]] into a bottomless chasm in the center of the [[Library]].
File:H2 Gravemind MC Arbiter.jpg|The Gravemind speaks to the Arbiter and SPARTAN-117 in the depths of [[Installation 05]], convincing them from stopping the Covenant from activating the Halos.
File:H2 S117 Boo.jpg|SPARTAN-117 is teleported by the Gravemind into the High Council Chamber of ''[[High Charity]]''.
File:H2 MK AJ Prisoners.jpg|[[Avery J. Johnson]] and [[Miranda Keyes]] of the UNSC taken prisoner and sent to [[Installation 05]] by [[Phantom]] dropship.
File:H2 Dreams and Hopes.jpg|[[Tartarus]] swears to the [[Prophet of Truth]] to use the [[Sacred Icon]] and activate the Halos.
File:H2 Cortana Gravemind Prisoner.jpg|[[Cortana]] captured by the [[Gravemind]] at the heart of [[Flood]]-infested ''[[High Charity]]''.
File:H2 Phantom Dropoff.jpg|A [[Phantom]] drops off [[Tartarus]] and [[Miranda Keyes]] at the [[Control Room]] shortly before Tartarus brutalizes Keyes to use the Index and activate the Halos.
File:H2 Mercy Dying.jpg|The [[Prophet of Mercy]] is killed by the [[Flood]], forever changing the Covenant's power structure, leaving the [[Prophet of Truth]] omnipotent over the Covenant.
File:H2 Tartarus Leads.jpg|Tartarus leads [[Miranda Keyes]] and [[343 Guilty Spark (Monitor)|343 Guilty Spark]] deeper into the bowels of the [[Control Room]].
File:H2 Arbiter Teleport.jpg|The Arbiter is teleported by the [[Gravemind]] to a high cliff south of the [[Control Room]] to find the [[Sacred Icon]].
File:H2 Tartarus Threatens Miranda.jpg|Tartarus snarls at Miranda Keyes to insert the [[Index]] into the panel and activate Installation 05.
File:H2 Arbiter Reasons Tartarus.jpg|The Arbiter attempts to reason with Tartarus not to fire the Halos, but to no avail.
File:H2 Tartarus Hits Johnson.jpg|Tartarus hurls [[343 Guilty Spark (Monitor)|343 Guilty Spark]] at Johnson, knocking him unconscious and then inserting the Index and preparing Installation 05 to fire.
File:H2 Miranda Retakes Index.jpg|Shortly after the Arbiter kills Tartarus, Miranda Keyes hastily removes the Index from its holographic panel, allowing Installation 05 to fire only an incompletely charged pulse.
</gallery>

==Sources==
<references/>
{{Clear}}
{{Human-Covenant War}}
[[Category:Battle|Installation 05]]
[[Category:UNSC Victories]]
[[Category:Installation 05]]