Second Battle of Installation 01

The Second Battle of Installation 01 was the final and most important engagement of the Forefather War. While being nowhere near the scale of the ongoing Battle of Installation 00, which involved the entirety of the Galactic Alliance's remaining fleet and the S'southi Armada, it served to be the decisive victory that the Galactic Alliance desperately needed to win the Forefather War.
==Background==
By August of 2566, the Galactic Alliance had been fighting the Forefathers and the S'southi for well over six years, and were very much on the losing side of the conflict. Despite the loss of the strong majority of the S'southi warrior class and several whole fleets, the S'southi were on the brink of victory with the Galactic Alliance having little chance at winning the war if it were to continue. As a result, the UNSC High Command greenlit a plan drawn up by Fleet Admiral James Coleman, in which the Galactic Alliance would feign a retreat to Installation 00. This plan banked on the fact that Binding Enlightenment, the leader of the Forefathers and therefore the S'southi, was blinded by his hatred for the Forerunners and it was believed that if he were to discover the Galactic Alliance's "retreat" to Installation 00, he would attack with all available forces. Then, Installation 01 would be activated over the Ark resulting in the complete annihilation of the S'southi Armada.
To assist with the plan, the Office of Naval Intelligence conducted a covert operation to make the Forefathers believe that the Galactic Alliance was indeed planning to retreat to Installation 00 due to "the untenable conflict with the S'southi". This plan was a major success, with the S'southi having very few sources of inside information in the GA left by 2566 and therefore the sources left were deemed incredibly trustworthy, alongside the fact that the S'southi were unable to conduct further investigations into this matter.
The UNSC Ivory Coast II Taskforce, a fleet lead by James Coleman, was assigned to the operation and was given additional resources to assist with the coming engagement. Alongside receiving the best weaponry, vehicles and munitions available to the GA at the time, the taskforce also received Three Spartan IIs, John 117, Theo 783 and Rose 788. In addition, several elite ODST and Spartan IV teams such as Fireteam India were also planned to partake in the battle. The S'southi, using their limited intelligence, caught wind of the UNSC's plan to deploy forces to the ring and sent a fleet to counter this movement, with the S'southi arriving first and establishing themselves on the ring.
== The Engagement ==
=== 25 August ===
==== Assault on Point Charlie ====
The UNSC Ivory Coast II Taskforce arrived above Installation 01 on the 25th of August and immediately deployed a large number of ground forces to assault the Installation's library, designated as Point Charlie. While the library no longer housed the index, it having been confiscated by the GA during the First Battle, it was still a very important strategic objective. Forward assault teams arrived lead by Fireteam India and the purpose-formed Spartan Team Ultraviolet consisting of John 117, Theo 783 and Rose 788. The elite forces deployed in the initial assault made short work of the S'southi defenses and brought the fight to the inner areas of the library, where UNSC reinforcements including heavy armour were deployed to assist in the push. Several Scorpion tanks alongside the Spartans were able to punch a hole through the S'southi and reach the inner sanctum of the library, resulting in the S'southi line being cut in half. UNSC ground forces quickly mopped up the remaining S'southi with the library being fully under GA control within an hour. Before the final S'southi forces were defeated, however, forward reconnaissance teams discovered the location of Kalam while investigating the ring's Control Room. Immediately, the three Spartans were deployed alone with Fireteam India intended as reserved reinforcements to assassinate Kalam and assume control of the Control Room.
==== Battle of the Control Room ====
The pelican containing John 117, Theo 783 and Rose 788 arrived near the Control Room shortly after sundown, and the three had to make their way into the Control Room on foot in order to ensure the S'southi did not learn of the attack. Silently dispatching several hostile patrols and teams within the vast tunnels and rooms that surrounded the Control Room, the three found themselves on a bridge where a large number of S'southi forces were stationed. With no other option but to engage them openly, the Spartans ambushed them and pushed across the bridge before the enemy could bring in aerial reinforcements, however the S'southi were now aware of their existence. With time running out, Fireteam India was deployed to assist the Spartans and the combined force pushed on the heavily defended control room. Despite being outnumbered and outgunned by vastly superior forces, the sheer lethality and skill of the Spartans and the resourcefulness of the ODSTs lead to the defenses being punctured with extreme ease and efficiency and the battle was brought to the interior of the control room. Kalam alongside his elite guards were prepared to engage the approaching humans in main control room, however John 117 neutralised the majority of his guards and severely wounded Kalam by taking and launching all of his and his allies' grenades into the room, obliterating the enemy forces within. After the room was cleared, Kalam was executed by Rose 788 and the UNSC began deploying reinforcements to secure the surrounding area.
===26 August===
====Defending the Control Room====
Shortly after the capturing of the Control Room and the arrival of a moderate number of UNSC reinforcements, the S'southi forces in the surrounding area began to desperately assault UNSC forces hoping to drive them back and retake the Control Room. Despite initial success, UNSC lines held and the S'southi suffered large casualties, forcing them to withdraw, suspending their attacks until sunrise. In the meantime, the AI construct Cassandra was retrieved by Theo 783 and brought to the Control Room where she was to enact the next phase of the operation. However, they were interrupted by the S'southi who had regrouped and began a new series of attacks in the morning. Forced to engage the enemy, Theo managed to survive the relentless attacks unharmed and put Cassandra into the ring's systems, where she then initialised a slipspace jump to the Ark. 
====Battle of the Abyss====
As the ring was now travelling through slipspace, the Forefather forces on the ring were sent into disarray, with no idea of what the GA and UNSC's plan was, however knowing that they were indeed heading somewhere unknown. Deep within the Forerunner structure known as the Abyss, originally a security facility within a set of massive artificial caves and now the headquarters of all S'southi operations on the ring. With Cassandra having full access to the ring's networks, and due to her Forerunner nature, the ability to utilise it to it's full potential, it did not take long for this facility to be designated as the site of the UNSC's next attack. In the early afternoon on the 26th of August, Fireteam India, Spartans John 117, Theo 783 and Rose 788 alongside a large number of marines entered the cave system through a large opening on the surface and were deployed deep inside of enemy lines, forced to engage the S'southi directly after their deployment. Marine forces fell quickly despite the rapid success of the attack, and the remaining forces grouped up and retreated from the structure itself with the aim to assault and capture an area suitable for the deployment of reinforcements within the caves. They saw great success, with the S'southi failing to effectively defend their positions within the caves despite having UNSC forces constantly sandwiched. The aerial insertion of additional forces began, with armoured and aerial assets being brought in to engage the S'southi in the cave systems. The Spartans Theo 783 and Rose 788 were tasked with assisting in the air combat within and around the Abyss facility, while John 117, Fireteam India and the bulk of the UNSC reinforcements lead a ground assault. By midnight, the UNSC had completely driven the S'southi into the Abyss facility itself and the battle transitioned to a close-quarters corridor-by-corridor struggle.
===27 August===
====The Death of Sark====
Combat within the Abyss continued long after midnight, with UNSC forces slowly pushing the S'southi back to the inner sanctum of the Abyss. John 117, Theo 783 and Rose 788 reunited and were tasked with investigating a sudden surge of energy in the higher levels of the facility. Fireteam India went with them, and they engaged the S'southi in fast paced, bloody combat as they ascended within the facility. Once they arrived on the second highest floor of the facility, they were suddenly ambushed by a contingent of S'southi veteran warriors which dealt heavy casualties to Fireteam India, killing or wounding all but four members of the fireteam and delivering minor wounds to Rose 788. Despite this, they managed to beat the ambushers and reached the top floor where they were then confronted by Sark and his elite guard. After dispatching the elite guard after an intense battle, Sark was slain in personal combat by The Master Chief, John 117. Despite their victory, Fireteam India had been whittled down to a single member, Victoria Theodorides, though the three Spartans remained relatively unhurt. It was at this point that the top level of the facility decoupled and began to ascend through the cave system, exiting through an opening and rising into the clouds above the Installation, at which point the Ring exited slipspace above the Ark, where the battle had already begun and was in full swing.
====Battle of the Confluence====
The "elevator" reached a facility that lay within the clouds known as the Confluence. Based on information accessed by Cassandra, the facility was originally a massive temple-like meeting area for builders and later became a massive garden-like series of structures. Despite not initially encountering any hostiles, S'southi forces immediately began to arrive from the fleet that was engaged in orbit around Installation 00, including the two remaining Forefathers, Binding Enlightenment and Arrogant Theory, and shortly after the S'southi arrived the Flood began to also arrive in pursuit. As it turned out, Binding Enlightenment had discovered the plan to activate the Halo and planned to prevent its activation by accessing the ring's internal systems from the Confluence. Now alone against a growing number of S'southi forces, John 117, Theo 783, Rose 788 and Victoria Theodorides were now in a race against the clock to reach Binding Enlightenment before he could enact his plan.
After pushing through the first structure, a pelican containing several marines and a Grizzly Tank arrived, allowing UNSC forces to push hard and fast towards their objective. Despite this, they were still running out of time, and the S'southi now controlled the airspace around the facility, making it very difficult for the UNSC to reinforce them. Regardless of this, the Grizzly Tank allowed them to fight off waves of S'southi forces as they continued their advance, but even this would not mean they were moving fast enough to stop Binding Enlightenment's plan from being set in motion. Before they could progress through the third large structure, they were assaulted by Arrogant Theory and a number of S'southi heavy armour and elite guards. The Spartans' marine allies quickly fell, however their Grizzly Tank obliterated the hostile armour and the guards, but Arrogant Theory's defense mechanisms temporarily disabled the tank. After a short engagement with the ancilla, Theo 783 punched a hole through the body of the ancilla and planted a grenade within, annihilating Arrogant Theory. Even though they had defeated one of the last of the Forefathers, Binding Enlightenment was still a threat and they had to move fast to catch up, abandoning the Grizzly Tank and taking a gondola that took them above the other structures, with a direct route towards the main temple. S'southi aerial forces intercepted the gondola multiple times, however the gondola's shielding prevented them from destroying it or harming those on it from the outside, forcing them to board it in an attempt to bring it to a halt. This failed, and the team reached the temple safely, now having to push through Binding Enlightenment's elite guards. At this point, the UNSC had been withdrawing from the ring for most of the day, and now, by midday, the team on the Confluence were the last of the UNSC forces actively engaged on the installation. In order to ensure they could stop Binding Enlightenment, GA forces in orbit deployed a final pelican with arms, munitions and a Gauss Hog. With the Gauss Hog, they fought their through the temple before reaching Binding Enlightenment's location, where he had already accessed the ring's systems and was close to preventing the ring from firing. At this point, Binding Enlightenment had believed he had won as Galactic Alliance forces, who had taken heavy casualties, were withdrawing completely from the battle above the Ark and did not consider the three spartans and lone ODST a threat. Unknown to him, the AI Cassandra was within the ring's systems still. After briefly engaging with and dispatching Binding Enlightenment's guards, which left Rose-788 and Victoria Theodorides moderately wounded, the squad engaged Binding Enlightenment and his defense mechanisms. Enlightenment proved to be a far stronger opponent than Arrogant Theory, and was, after taking a moderate beating, able to disable the armour of two out of three of the Spartans. Believing it was just John 117 left standing, the construct turned its undivided attention to him, which would be the cause of it's defeat. Victoria Theodorides ignited a S'southi grenade and jumped onto Binding Enlightenment from the back, severely damaging him and lethally wounding herself in the process. The Spartans suits were now active and John 117, Theo 783 and Rose 788 all defeated the almost destroyed Binding Enlightenment as a team. With the ring's firing sequence now activated by Cassandra, Theo removed her from the system and harboured her within his suit as the team began to retreat from the structure in the Gauss Hog, escaping to a nearby hangar and commandeering Binding Enlightenment's shuttle, allowing them to retreat into slipspace before the Halo fired and wiped out all sentient life near the Ark.
==Aftermath==
The direct aftermath of the Battle on Installation 00 and it's activation above the Ark was felt across both the Andromeda and Milky Way galaxies. With the eradication of the entire S'southi Armada above the Ark and all of it's key leadership, the S'southi forces that remained in the Milky Way descended into chaos, effectively ending the Forefather War. Most retreated to Andromeda, while others were hunted down and slaughtered by Sangheili-led "kill-fleets". In Andromeda, the home galaxy of the S'southi, their empire completely dissolved and galaxy-wide turmoil and anarchy ensued, effectively ending the S'southi as both a threat and a political entity. 
The Galactic Alliance, being an entity entirely created to defend the known galaxy against the S'southi invasion, began to dissolve. The UNSC and the Krythenan Empire remained unified under the Alliance while every other faction returned to their pre-war independence, though despite the new lack of unity, peace descended upon the galaxy. Each faction had fought together for six years, were badly bloodied and were unwilling to engage in further conflicts due to how devastating the Forefather War had been, resulting in almost total peace and status quo across the galaxy.
Victoria Theodorides was posthumously given several awards by the United Nations Space Command, Lights of Purity, Restored Krythenan Empire and most of the brute-led Covenant sects for her services during the final hours of the battle. Cassandra, an AI that had long plagued the UNSC alongside her ally Kayode Adetola, was brought into ONI custody but was soon broken out by Adetola.