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Greetings. I am the monitor of Installation 04. I am 343 Guilty Spark.
~ 343 Guilty Spark introducing himself to the Master Chief for the first time.

343 Guilty Spark, also referred to simply as Spark or as The Monitor, is an AI Monitor created by the Forerunners and one of the main antagonists of the Halo series. He is left to watch over Installation 04 and its contents when the Forerunners departed.

He appears as the main antagonist of Halo: Combat Evolved, an anti-hero in Halo 2, and the secondary antagonist of Halo 3.

As with UNSC and Covenant artificial intelligences, Guilty Spark's programming prohibits certain actions outside of his function. He cannot, for example, retrieve the Index from the Library or unify it with the Core, instead needing a Reclaimer to carry out this task.

He was voiced by Tim Dadabo.


343 Guilty Spark is a small robot with no limbs. He has a sphere for a sensor, which can either be the color blue or red.


Built by the Forerunners, 343 Guilty Spark had been present on Installation 04 for some 101,217 "local years" and participated in plenty of test firings and in one actual firing of the installation prior to the Battle of Installation 04. Little else is known about his history. Presumably, he had been the Installation's first and only Monitor, attending to all of the duties pertinent to that station, such as aiding in maintaining the structure, combating any Flood outbreaks, etc. However, he became rampant at the attempts of the Master Chief to destroy the Ark, killing Sergeant Avery Johnson, which subsequently forced John-117 to destroy him.

The Flood Outbreak

The arrival of the Covenant on the ring instigated Installation 04's genocide, and the final Flood outbreak. Immediately putting long dormant contingency measures into action, Guilty Spark began to search for a Reclaimer and discovered UNSC Staff Sergeant Marvin Mobuto. Using Halo's teleportation system, Guilty Spark brought Mobuto to the Library in an effort to retrieve the Index. Ultimately, although he fought hard, and endured the flood almost to the index, the ill-equipped Marine failed and was killed, forcing the Monitor to seek out another Reclaimer. The Master Chief discovered the body of Mobuto (which was mangled beyond usage by the Flood) during his own journey through the Library, though it can't be seen in-game, and marveled at the Staff Sergeant's ability to get as far as he had. 343 Guilty Spark encounters the second Reclaimer. 343 Guilty Spark and a few Sentinels moved to the Flood Containment Facility to aid the Marines and the Master Chief, who were battling the Flood. Here the Monitor recruited the Master Chief as the next Reclaimer, who he quickly teleported to the Library and began guiding to the Index. With superior equipment and training, and despite overwhelming odds, the Master Chief succeeded in retrieving the Index. Taking the Index for safe keeping, Guilty Spark teleported himself and the Master Chief back to the Control Room. Here, safe from the Flood, the Index was returned to the Master Chief. The Monitor explained that he was not permitted (by his programming) to reunite the Index with the Core, thus activating the Installation. Only a Reclaimer could do so. 343 Guilty Spark in Halo’s Control Room. However, Cortana, still in the Core, took the Index before it could merge with the Core and explained to an ignorant Master Chief about Halo's purpose. 343 Guilty Spark confirmed this information, claiming that he had believed the Master Chief to have been aware of 'his' role and responsibility. With the Index in the possession of a hostile AI and protected by the now uncooperative Reclaimer, the Monitor turned the Sentinels against the Master Chief to attempt to retrieve the Index. This attempt failed and Guilty Spark was forced to seek an alternate way to activate the ring and destroy all sentient life {C}343 Guilty Spark downloading data from the Pillar of Autumns computers. After the encounter the Master Chief disabled the three Phase Pulse Generators, forcing their repair and delaying 343 Guilty Spark's plans. Disappointed by his lapse of judgment, the Monitor followed the Master Chief and Cortana to the Pillar of Autumn where he began to download the ship's data banks, being especially interested in the parts pertaining to Human history. He then disabled the vessel's automated self-destruct system to preserve the repository of knowledge he had discovered. Although the warship's engineering room was protected by many Sentinels, the Master Chief was successful in destabilizing the power cores. Realizing the implications of the ship's destruction, the Monitor immediately made to flee the doomed ring. Moments before the ring was destroyed, the Monitor decided that he had done his utmost to fulfill his responsibilities. Later upon further reflection, when he was floating through space, Guilty Spark found himself happy as, ultimately, his purpose had been fulfilled: the Reclaimer had indeed succeeded in stopping the outbreak, even if it had been done “inelegantly.”

After Halo

After Halo's destruction, Spark moved aimlessly through space (as seen in the after-game credits) 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 Master Chief's character. However, a short time later, Spark was saved by Sesa Refumee. Within a few weeks of the ring's destruction, Guilty Spark was retrieved by a group of soldiers of the Covenant, to whom he was known as "the Oracle". Spark attempted to educate these soldiers about, amongst other things, the rings' true purpose. Exposed to the truth, one Sangheili in particular (Sesa 'Refumee) took a new, critical view on the Great Journey and, gathering other similarly minded Elites and Grunts, founded a new sect that denounced the Prophets and their Great Journey as false. These became the Heretics, who set up a base on a Forerunner gas mining facility in Threshold's atmosphere, where they continued to be "enlightened" by 343 Guilty Spark as to the true purpose of the Forerunner creations. The Oracle with the Heretic Leader Sesa 'Refumee such a state of affairs could not be tolerated for long by the Covenant and soon action was taken to eliminate the Heretics. This was accomplished quickly and quietly by the Arbiter and a team of special operations troops. In the aftermath, Guilty Spark was captured by Tartarus and given to the Prophets aboard High Charity. Tartarus holds 343 Guilty Spark prisoner as he tries to force the activation of Delta Halo. Interrogated by the High Prophets, Guilty Spark revealed the nature of the Installations and the means to employ them, which made the Prophets send the Arbiter to retrieve Installation 05's "Sacred Icon". After it had been obtained, Tartarus took Guilty Spark and the Index to Installation 05’s Control Room, using Miranda Keyes as the new Reclaimer. However, Tartarus grew tired of Guilty Spark's constant warnings. When the Arbiter and Avery Junior Johnson arrived to deactivate the ring, they first questioned Guilty Spark, so that he'd reveal Halo's true purpose. However, the Brutes were too loyal to the Prophets to accept this truth. 343 Guilty Spark escaped Tartarus' clutches and stood by and watched the ensuing struggle, reminded of the one he had witnessed on the Pillar of Autumn. After Tartarus and his Brute Captains were killed, the control panel for the Installation began to show a holographic display. 343 Guilty Spark translated the display to Johnson, Miranda Keyes, and the Arbiter. The rings were now on standby, meaning they could be activated from the Ark. The Arbiter asked Spark where it was, and he directed them to a specific location, which turned out to be Earth, the Human homeworld.

Earth and The Ark

Guilty Spark aiding Human and Sangheili forces near the Cartographer building.Spark arrived on Earth with a Fleet of Covenant Separatists in order to help them search for a storage device. He found the object, along with Master Chief, and killed a Combat Form that was about to attack the Chief. After a tense exchange between the two, they put aside their past and proceeded to bring the device back to the ship. 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, the Chief, Johnson, Keyes and the Arbiter, along with Separatist forces traveled through the recently-opened Portal; Spark joined them. The Fleet followed the Loyalist forces through the portal, and came across a large Forerunner Installation similar to the Halos but not in ring form. Upon touchdown, Spark sent orders to all Sentinels that the incoming UNSC and Separatist forces were friendlies, therefore reducing the likelihood of friendly fire incidents. Searching for Truth's location, the Separatist Sangheili located the construct's Cartographer. Spark followed the Chief and the Arbiter's platoons to penetrate the wall protecting the location, opening doors and providing Sentinels as backup for the assault. Once the Cartographer was found, Spark revealed they were beyond the rim of the Milky Way Galaxy and told the Chief the Installation they stood upon was the Ark. Using the map system, Spark found the Prophet of Truth's location several hundred kilometers away, but he was shielding his location utilizing a barrier installed by the Forerunners. At that moment, a Loyalist Phantom arrived, driving the trio back deeper into the hallways. Spark led them towards Johnson's location a few floors below. After the reunion, Johnson was nervous at the sudden appearance of hundreds of Sentinels, but Spark reassured him they meant no harm and were part of a primary task force, although, not being native to the Ark, he couldn't discern their goal. UNSC and Separatist forces moved to disable the shield barrier protecting Truth. However, once the barrier was taken down, High Charity appeared from out of Slipspace, nearly destroying Rtas 'Vadum's ship, and spread debris and Flood everywhere on the Ark. Terrified of a complete takeover, Spark insisted that they focus their attention on the Flood. He was met with opposition from Keyes and the Separatist leaders, who made it clear that their first priority was to kill Truth before moving on to the parasite. Once the Prophet of Truth was dead, the Flood began their infestation under the command of the Gravemind. Spark met up with the Arbiter and Master Chief after their initial escape, only to reveal that the Forerunner constructs began the construction of a new Halo ring, to replace Installation 04. When asked what he would do with the Halo system, Master Chief 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. After rescuing Cortana from the Flood-infested High Charity, Master Chief, the Arbiter and Johnson landed on the newly constructed ring. Spark aided their progress through the Installation by providing Sentinels to combat the Flood. Once the initial wave of Combat and Pure forms were destroyed, Spark opened the main blast door to the Control Room.

Return to Halo

Spark reunited with the Chief, along with Johnson and the Arbiter in the new Installation 04's control room, telling them the ring was almost completed. However, regardless of being informed that activation would destroy the ring, Johnson was adamant to fire anyway, determined to destroy Gravemind forever. Upon realizing this, an outraged Spark retorted violently and fired upon Johnson to delay activation of the ring, mortally wounding him. He made claims that the ring was his, perhaps driven rampant by guilt, having already lost a different ring. Seeing the Master Chief running towards his fallen comrade, the Monitor fired upon him and the Arbiter, knocking the Arbiter out of the room and sealed the entrance behind him. The Master Chief was left to face the Monitor alone. With the Chief on the floor with his shields down, Spark made it clear that he would stop at nothing to follow protocol and ensure the safety of the ring and the Ark. Although protocol stated that the structural integrity of Installation 04 (then 04B) must be protected from damage, primary protocol overwrites this, which stated that an imminent Flood outbreak should be contained immediately. Thus, if immediate containment procedures would cause massive structural failure to Installation 04B, and delayed action would negate containment procedures, the overwrite command should have been executed and allowed the self-destruction of the installation. It would then be fair to say that 343 Guilty Spark was defunct and ignored protocol for the sake of self-preservation. The Chief engaged the Monitor in combat unsuccessfully and it looked like John was about to die when SgtMaj. Johnson used his Spartan Laser to blast Spark's protective casing, exposing him to fire. Johnson then gave his weapon to John, giving him the means to end Spark's rampage, and telling him to "kick his ass". Spark began to malfunction ever more erratically as John destroyed him with the Spartan Laser. After precisely 3 hits, he finally succumbed to the stress, and exploded. Though, with his last sane words, calling John-117 "Forerunner", deepens the mystery, rather than solving it. This has led to much speculation, such as that of implying that John was a direct Forerunner descendant rather than just being influenced by them, though this may be a result of the Monitors' compartmentalization that limited his knowledge.


343 Guilty Spark's personality is somewhat egotistical and eccentric. The long period of isolation experienced by it may have contributed, or even been the cause, of much of this. 343 Guilty Spark is in a state of Rampancy; although he is still accepting of his role as Monitor, his pursuit of alien knowledge does seem to go beyond his purpose. Since it was his job to manage the Flood, he was also trained to learn. It was intended for him to learn so he could stand ready for any changes in the Flood. However this system is his greatest weakness and he applies it to everything. He loves to learn and to take records; even if he has to force it out. While egotistical much of the time, he seems to be aware of the limitations of his knowledge, such as when he perceived Installation 00 to be part of a Shield Installation, and not what it was all along. 343 Guilty Spark had quite an erratic and abnormal personality, and a disregard to Human and alien life alike. He seemed almost effervescent and gleeful when, in Halo 2, he told Miranda Keyes there was no way for him to halt or cease the firing of Installation 05, showing a great lack of respect and deference for Humanity and Covenant life. This may be due to certain programming parameters. He, like 2401 Penitent Tangent, seems quite eager to activate the Halo Array, perhaps hinting that there is a certain gratification they receive in helping their masters. His strange personality was shown in the way he would randomly and with no clear lucid pattern say things such as: 'Ah, I am a genius!'. In Halo: CE, when helping Master Chief, he was constantly humming and giggling. It is also interesting to note that he finds the religious rich conversation of the Covenant tiring. Terms such as "Oracle", the "Sacred Icon" and "Sacred Rings" frustrate him as the Covenant, with their limited knowledge about the Forerunners continue to use obscuring, meaningless titles for various objects. Spark's eagerness to activate the rings at the slightest provocation seems unlike the wishes of previous Forerunners, who, by Spark's own admission, had used the Halo Array as a last resort. Spark's behavior indicates he sees the array as the only resort, as he wishes to use it before the Flood has even escaped the ring. At no point does he attempt less extreme actions, such as disabling and destroying any possible escape ships for the Flood to use.


The laser of 343 Guilty Spark used to attack his enemies. 343 Guilty Spark, using his force field after turning rampant. 343 Guilty Spark has been seen using five known weapons. The first, shown in Floodgate, is a red beam that is similar to, but more powerful than, Sentinel Beam—the beam is powerful enough to mortally wound Sergeant Johnson and completely drain the Master Chief and the Arbiter's shields. The second weapon is a force field projector that repels objects; it was likely meant to be used when overwhelmed by Flood. The Monitor is also equipped with a third weapon, which is a thin blue laser that can unlock doors on The Ark and deliver a painful but non-fatal electrical shock or laser burn. The fourth is a similar variant, being a white laser that can be used to levitate and manipulate objects, which Spark used to the Separatists’ benefit at Earth by repairing the Covenant Storage Device containing Cortana’s message. The final known weapon that the Monitor used is an unusual beam resembling blue electricity which was used by Spark at the Pillar of Autumn to download data from the ship’s databases into Spark’s own files, allowing him to shut down the ship’s countdown sequence and delay the activation of its reactor.



            Halo.png Villains

The Flood | Huragok | Mgalekgolo | Jiralhanae | Kig-Yar | Sangheili | San Shyuum | Unggoy

Covenant Empire
Covenant High Council: Prophet of Truth | Prophet of Mercy | Prophet of Regret
Covenant Sangheili: Ardo 'Moretumee | Bako 'Ikaporamee | Field Marshal | Lat 'Ravamee | Luro 'Taralumee | Merg Vol | Ontomee | Re'gish Wamik | Rho 'Barutamee | Ripa 'Moramee | Rtas Vadum | Thel 'Vadam
Covenant Jiralhanae: Lepidus | Parabum | Tartarus

Storm Covenant
The Didact | Jul 'Mdama | Gek 'Lhar | Parg Vol | Kitun 'Arach

Cortana | Warden Eternal | Guardians | Prometheans

The Banished
Atriox | Decimus | Let 'Volir

Office of Naval Intelligence
James Ackerson

Jerald Mulkey Ander | Robert Watts

343 Guilty Spark | Commissioner Kinsler | Gravemind | Heretics (Sesa Refumee)

Halo: Legends
Harka | Pluton

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