343 Guilty Spark has had a very long and, for the most part, uneventful 'life'. But his story does begin before his creation, it starts with a Hamanune named Chakas who lived on Erde-Tyrene around 101,217 B.C.E. Chakas was friends with the human Morning Riser, and together they were guides to the young Forerunner Manipular Bornstellar on his quest to adventure. They led him on an expedition to the Djamonkin Crater, where Bornstellar found a Cryptum containing the Didact. It was here that Chakas' and Morning Riser's geas gave them the instructions to sing a very particular song in order to open the Cryptum. This geas was implanted in their DNA by the Librarian as she wanted to eventually release her husband from captivity.
The Didact had been in de Cryptum for a long time, and travelled with him to the San'Shyuum homeworld Janjur Qom in an attempt to trigger hidden memories left by the Librarian in the Didact's mind. As they approached the system, Chakas and the rest were imprisoned by the Master Builder. At a later date Chakas would be released on the Halo Array Installation 07 after the Master Builder comes under attack from the rampant AI 032 Mendicant Bias and the The Primordial.
Now on Installation 07, Chakas and Morning Riser were in an area infested with Flood biomass. During their way out, after traveling through the Flood-infested landscape for days, Riser eventually came to its edge and made his way to a plateau. Here they encountered a group of humans and an ape led by a Forerunner Lifeworker which, highly suspicious to Morning Riser, cast off no scent. Observing this group for some time, they finally made contact and were fed by the Lifeworker. During the following night, Morning Riser came to Chakas' hut and explained that he did not trust them, and so shouldn't Chakas. Indeed, it was soon revealed that the Lifeworker and the humans were actually archived personalities present only as holographic simulations; these illusions disappeared as the area experienced a power outage. After travelling for a long while, they eventually came across a rail transport and boarded it. The transport took them to a Lifeworker research station, where they entered a boat-like vehicle with an uncertain destination.
This transport took them all the way into the lair of Mendicant Bias where Chakas was interrogated by the rampant AI. During this, attempts were made by the Forerunner Ecumene to stop Mendicant Bias. One attempt was enacted by rogue Lifeworkers, which attempted to destroy the Installation by crashing a planet into it. During Installation 07's manoeuvre to avoid the impending collision, Chakas was mortally wounded and Bornstellar transferred Chakas' consciousness and memories into a monitor in an attempt to preserve Chakas' intellect and ancient memories caused by his geas. Now known as 343 Guilty Spark, he was given the task to watch over Installation 04
1.2 trillion simulated, 1 actual
While on Installation 04, Chakas's consciousness continues to bleed into 343 Guilty Sparks, until 343 Guilty Spark has access to Chakas' entire memory and most of all geas. Spark uses his 'new' knowledge to find the Librarian, so she could help him rescue Morning Riser. It turned out that Morning Riser had survived his ordeal, was transported to the Lesser Ark for some time and was now presumed back at Erde-Tyrene. When the raging Forerunner-Flood war reached its epic climax, Spark was forced to witness the destruction of all sentient life in the galaxy as all 7 active Halo Arrays were fire simultaneous.
343 Guilty Spark was lone in a galaxy void of sentient life, and spent eons monitoring Installation 04. In order to keep busy, he oversaw the simulation of tens of thousands Halo firings per day while keeping in contact with the monitors of the other installations. When the connection between Installations was severed, Spark suffered from loneliness, sometime even he had not thought possible for an AI. During this unintentional exile, he would begin to recollect his time spent with the Forerunner, their war with the Flood, decisions they made, and decisions he believed they should have made.
"Looking back, we should have done a few things differently. For one thing, we should have installed two caretakers per installation. Because I am alone, I am losing focus. And that is very, very dangerous for a system such as myself."
Circa 40,000 BCE, an alien vessel crash-landed in Installation 04’s Sector 1215. Though anxious to find answers for whether the Forerunners’ plan to reseed life in the galaxy had been successful, Spark acted in accordance with protocol, blocking the distress signal sent out by the ship and not attempting to make contact with any possible occupants. No lifeforms exited the wreckage and the distress signal eventually terminated, offering Spark no answers. Afterwards, the monitor had a containment sarcophagus constructed around the ship. During his long isolation, Spark observed one or more space faring species visit and explore Installation 04. These species recorded their findings and eventually left without breaching containment.
Greetings, humans, and welcome to Installation 04
While Spark was on the ring, somewhere else in the universe, the Human-Covenant war was raging on. The Covenant's attack on a human planet proved successful, but one ship fled the carnage. Commanding all the ships in his command, the Supreme Commander Thel 'Vadamee pursued the ship through Slipspace. The Autumn ended up in close proximity of Installation 04, and their arrival was soon noted by Spark. At first Spark warned the ship to jump at least one light-year away from the Installation or be destroyed but realised that the ship was manned by Reclaimers after finding data on human history. He then deactivated the ring’s defensive systems.
After the Human-Covenant skirmishes on the ring led to the inadvertent release of the Flood spores held in the Flood containment facility, Spark went looking for a Reclaimer so he could activate the Installation to contain the Flood. At first, Spark came upon Staff Sergeant Marvin Mobuto who was brought to the Library to retrieve the Activation Index. Even though Marvin showed great skill and perseverance, he was ultimately overwhelmed and killed by the Flood and Spark had to search for another, better equipped, Reclaimer. The second Reclaimer he found was one with more advanced equipment and skill, and SPARTAN John-117 was taken to the Library to retrieve the Activation Index. He succeeded, and together with John, Spark teleported to the Control Room. The Monitor explained that activation protocols forbid him from personally uniting the Index with the Core to activate the ring; only a Reclaimer could be permitted to do so.
But before the protocol could be completed, the human AI Cortana intervened in the activation of the Installation. Cortana explained that the activation of Halo meant the destruction of all sentient life in the vicinity, and the Reclaimer became uncooperative to Spark's requests. With the Activation Index in the hands of a foreign hostile AI, and no Reclaimer present willing to activate the Installation, Spark sent Sentinel Drones to retrieve the Index. During their escape through the Control Room’s adjacent tunnels, John-117 disabled the 3 phase pulse generators, which would need to be repaired before the Installation would be ready to fire. Delaying the containment of the Flood outbreak even further, Spark then followed John and Cortana to their ship, where they planned to destroy the ring by detonation. As Spark identified the treat to the Installation, he disabled the self-destruct sequence set in motion. As he thought the threat over, he then started to probe the Autumn's computer and was intrigued by the human history stored on there.
As Spark had disabled the self-destruct sequence, John-117 began to fight his way to the warship's engineering room to destabilise the power cores and trigger the detonation himself. After John had successfully triggered the explosion, Spark quickly fled the Installation. Moments before the Installation's destruction, 343 Guilty Spark reflected that his purpose to contain the Flood outbreak had been successful and that he had done his best to prevent the destruction of the Installation under his care.
The Lone Wanderer
Having no Installation to monitor, 343 Guilty Spark began to move aimlessly through space. Thinking and re-thinking what had happened to him and how the Reclaimer had betrayed him and destroyed his Installation. He began to wonder how he made such a mistake in judging John-117's character.
He later headed towards the local gas giant Threshold, where a Forerunner mining facility, that also doubled as a Flood Research Facility consisted. Unknowing to Spark, a Covenant detachment was sent to investigate the facility prior to his arrival. Upon entering the facility, he was attacked by several Kig-Yar, until a passing Sangheili noticed and killed his attackers. Spark was then taken to their leader Sesa 'Refumee. After being informed by Spark that the Halo rings were a weapon, Sesa cut off all communications to the Fleet until he heard all that Spark had to say. Sesa then told the rest of the Sangheili and Unggoy of what Spark had told him. They then renounced the ways of the Covenant and became Heretics.
The Covenant's retaliation of this heresy was to send the now-Arbiter Thel 'Vadamee to silence the Heretics. As Thel successfully defeated Sesa, 343 Guilty Spark was taken prisoner by the Jiralhanae Tartarus and brought before the Hierarchs. Here, Spark was greatly confused by all the wrong terminology for the functions of the Halo Arrays and did his best to explain his Installation's functions. As the Jiralhanae were too loyal to the Great Journey, they were only angered by Spark's explanation. As human forces breached the Installation, Spark was freed from Tartarus and witnessed the elimination of the Jiralhanae at the hands of Avery Johnson, Miranda Keyes and Thel 'Vadam. As the Activation Index was pulled before the ring could fire, all other Installations were now put on standby mode, so they could be remotely activated from Installation 00, the Ark.
To the Ark
As Spark believed it was the humans intent to fire all Installation from the Ark to destroy the growing threat from the Flood, he helped them locate the Artifact which would lead them there. As Spark arrived on Earth with the Swords of Sanghelios he went and looked for a storage device located on the Indulgence of Conviction. The device contained a transmission from Cortana that she was still on High Charity. She claimed she had a solution to stop the Flood without activating the other Halo rings. In order to discover the answer, John, Avery, Miranda, Thel, along with Separatist forces travelled through the recently opened Portal; Spark joined them.
At the Ark, Spark deemed highly helpful, as he opened the way towards the Control Room. As soon as they made it to the Control Room, it became apparent that the Ark was busy building a replacement ring for the destroyed ring. When asked what he would do with the Halo system, John-117 replied, "light it." This cheered up Spark, who was thrilled the Flood would finally be dealt with for good. He went off to set up preparations for the firing sequence.
Spark reunited with John, along with Avery and Thel in Installation 04B's control room, telling them the ring was almost completed. However, regardless of being informed that activation would destroy the ring, Avery was adamant to fire anyway, determined to destroy the Flood Gravemind forever. Upon realizing this, an outraged Spark retorted violently and fired upon Avery to delay activation of the ring, mortally wounding him. In the ensuing fight, 343 Guilty Spark was heavily damaged, apparently defeated. John-117 then activated the ring and the ensuing destruction of the ring took the Ark with it.
Spark was not completely destroyed, however. Between 2553 and 2557, the UNSC detected a transmission from the ruins of Installation 00 and deployed the UNSC Rubicon to conduct a further investigation. They recovered an extremely damaged armature, believed by the team to be the source of the signal picked up by the initial investigative group. The device was actually the broken, barely active remains of 343 Guilty Spark.
After properly calibrating their AI translator, the human team began to interrogate Spark, hoping to gain insight into the ancient human-Forerunner relations and the Didact. Spark, acknowledging the humans as "the true Reclaimers" and claiming that his duty was to eventually testify to Reclaimers when given the opportunity, proceeded to describe the events that led to his former human self-becoming a monitor. Over the course of his narrative, he constantly accessed the ship's information stores, breaching the firewalls without effort, much to the ONI team's dismay. As a result of the extensive damage he had sustained, Spark's memory was heavily splintered and barely functional; for example, he was unable to remember many of the preceding events, only learning of his recent interactions with the humans after tapping into their records and even then, assuming the monitor in question being a separate duplicate of himself.
After Spark had finished his story, his robotic shell finally powered down and was jettisoned into space by order of the ONI team commander. Before this, however, he had successfully managed to upload his data stream into the ship's computers, disabled its AI, and took full control of the vessel. Having come to the conclusion that the Librarian was alive as a result of long study, and that he had need for the ship and its crew, Spark put them to sleep and set course to where he believed the Librarian could be found.