Monitor

The Monitors are highly advanced Artificial Intelligence constructs created by the Forerunners 100,000 years ago to service and maintain the Halo installations, and to ensure that the deadly Flood stayed imprisoned.

Monitors are extremely intelligent, yet completely devoted to their original function. They are zealous about containing the Flood: monitors have been known to turn violently on their allies if the latter should attempt to violate their containment protocols. The only real example of this is when 343 Guilty Spark turns on the Master Chief and attempts to kill him, and then does the same to Johnson and succeeds in killing him. This is evidence of 343 Guilty Spark possibly having gone rampant. This is quite possible as he was stuck on Alpha Halo for thousands of years.

The Covenant refer to the Monitors as Oracles. Humans (notably Sergeant Major Avery Johnson") have called them Light Bulb, Tinker Bell and Robot, and the Master Chief calls 343 Guilty Spark Spark.

There is one known monitor per Halo Installation, except in the case of Installation 05, where 2 Monitors have been found; 2401 Penitent Tangent and a larger Monitor implanted in a wall on the Multiplayer Map Cold Storage.

Appearance
The body of a Monitor consists of a roughly spherical shape, concave on three sides, with an illuminated photo receptor/eye with the Marathon logo on it located on the "front" of the orb. A monitor's silvery metal covering is reminiscent of other Forerunner constructs. All the monitors seen so far speak in a tinny, but level, male voice.

It is unknown if the colors of the monitors are individual for each monitor or if they change due to action or emotion.

When firing it's own weapon, 343 Guilty Spark's blue light will turn red and emit the laser.

Features
Halo's Monitors seem to have a defensive resistance to small arms fire, though they will eventually succumb after taking extensive damage. In the novel, Halo: The Flood, Master Chief fired half a magazine from an MA5B Assault Rifle at 343 Guilty Spark with no apparent effect. In Halo 3, Master Chief destroys 343 Guilty Spark using multiple shots from a Spartan Laser, demonstrating that Monitors can sustain damage from high power weaponry. Should a Monitor be damaged, it is capable of self-repair.

Each Monitor commands the Constructors, Sentinels, Sentinel Majors, and Enforcers of the Installation they are based on. The latter two are only activated if a catastrophic outbreak occurs, to hold back the Flood, while the Monitor locates a Reclaimer. Although such Constructs are programmed to assist the Monitors in combat-oriented tasks, the Monitors themselves are capable of producing a powerful orange-red beam from their "eye" that is powerful enough to bring down the shields of a Spartan, or stun, and maybe even kill an armored human. Though the Monitors seem to have endless knowledge of their own Installation, the Forerunner limited their knowledge of all other constructs in the case of an absorption by the Flood.

Monitors have the ability to teleport themselves and others around their Installations. It is unclear exactly how this teleportation works, but it seems that a Monitor on an Installation other than its own has no access to that Installation's transportation grid. In the book, Ghosts of Onyx, Dr. Halsey comments that Onyx's teleportation matrix is powered by a Slipspace generator of some sort. The Monitors may use similar technology when teleporting.

Monitors keep daily logs of all things that occur on their Installation. As with UNSC AI, the Monitors have been speculated to be in stages of Rampancy, due to their isolation for literally hundreds of thousands of years.

Known Monitors

 * 032 Mendicant Bias (possibly the monitor of Installation 00)
 * 343 Guilty Spark (Installation 04)
 * 2401 Penitent Tangent (Installation 05)
 * Cold Storage Monitor (Installation 05)

It is unknown whether Penitent Tangent's red color is due to some malfunction (or due to his proximity to Gravemind). Important to this debate is the consideration that 343 Guilty Spark changes hue when he experiences Rampancy, going from his regular blue to a bright red color. Penitent Tangent, however, seems perfectly aware of protocols such as conduct towards possible Reclaimers, something that 343 Guilty Spark forgot during his rampancy. 343 probably went early in his service rampant after seven years the UNSC AI were decommissioned so after all Guilty Sparks years in service would send him mad only needing a trigger. It is likely that the color change signifies an occurring error in the monitor's programming. Hence Guilty Spark turning red when Johnson tells him of their plan to destroy the new installation. Also Penitent Tangent's red coloring could be due to its capture by the gravemind and resulting errors or protocol.

It is also thought that the full designation of each Monitor comprises of the Installation Number of the installation the Monitor in question is assigned to, then 7(a reference to bungie's love for the number seven) to the power of that one less than that number, then the adjective/noun name of the Monitor (i.e. 04-343 Guilty Spark).

Trivia

 * if you look closely at 343 Guilty Spark's visor you can see the Marathon symbol.
 * When the numbers of each Monitor are examined, a pattern emerges: each seems to be seven raised to the power of the Installation number minus one; therefore this grid can be founded. (Note that the first three digits of the monitor of Installation 07 are 117, Master Chief's service number.)
 * On the level The Ark, if you start at the second Rally Point and you betray all the Marines, Guilty Spark will fire his laser at you. Even on Easy difficulty, the laser is almost an instant kill. However, on the final level when you are supposed to kill him, his laser barely does an significant damage compared to his laser on The Ark.
 * The 'eye' of 343 Guilty Spark resembles the Marathon symbol - only one of many references to this series that appear in the Halo series. It is also believed to be the Reclaimer symbol.
 * It is revealed in Halo 3 that the Monitors, or at least the most prominent Monitor, 343 Guilty Spark, have offensive capabilities very similar to that of a Sentinel, which can stun or immediately kill an opponent. 343 Guilty Spark primarily utilized this ability two times in the third installment of the series: once to destroy a Flood Combat Form that was about to attack Master Chief, and later to fight the Chief and the Arbiter, and to kill Sergeant Johnson. 343 Guilty Spark may also use the effective beam on the level, The Covenant. When you join the Arbiter after defeating the two Scarabs, 343 Guilty Spark may fire at any enemy that gets too close to the bridge. He will also use it when the player kills too many Marines and causes all allies to shoot at the player.


 * The voice effect can be achieved by flanging, a technique often used for electric guitar.
 * It is possible that if a Monitor of an installation is destroyed, all Sentinels under its control will attack any beings on the ring. Evidence to support this is the destruction of 343 Guilty Spark and all Sentinels attacking you thereafter. Though it is also possible that upon going into his rampant state, he added the Master Chief and the Arbiter onto their targeting ledgers.
 * Monitors' eye color matches the color of the holo-images on Installation 00. Installation 04's color is a Blue while Installation 05's color is Red.
 * Guilty Spark's name is similar to Penitent Tangent; both Penitent and Guilty have very similar meanings:
 * Guilt (Guilty) - remorse or self-reproach caused by feeling that one has done something wrong.
 * Penitent - Feeling or expressing remorse for one's misdeeds or sins.
 * An alternative to the theory that the Spartan Laser simply deals so much damage that it can destroy a Monitor is that a Monitor's shields do not protect against light, which means that light-based weaponry, such as the Spartan Laser, could easily damage a Monitor. If the shields blocked light, Monitors would have no way of seeing. This is contradicted, however, by the ability of the Rocket Launcher as well as the Fuel Rod Gun to damage Spark's casing, albeit, less efficiently. Although this may be since the Spartan Laser cracked his casing and shielding, the Human Launcher and Fuel Rod Gun was able to damage him further.
 * Another alternative to this theory is that Monitors can only be damaged by Radiation; Laser stands for Light Amplification by Stimulated Emission of Radiation, and that the Fuel Rod Gun uses Radioactive Fuel Rods for ammo. However, this is contradicted by the fact that the Rocket Launcher can damage Guilty Spark's casing.
 * In the multiplayer map Cold Storage, a large Monitor can be seen embedded in the ceiling which follows your movements, as long as you are in the same room as it.
 * Marty, Jason, and Joseph jokingly referred to Monitor 7 as "7 Broken I-pod" and 49 as "49 F****** lightbulb".
 * All monitors so far, with the exception of 2401 Penitent Tangent, have the same design as 343 Guilty Spark, examples including Forge Monitors and the Cold Storage Monitor.
 * For unknown reasons (possibly the shape and design of monitors) you cannot be run over or splattered by objects like tanks or boxes in edit mode. If someone takes one of the large boxes in Foundry and tries to crush you, you will simply slip out from under it, unlike if you were in player mode you would be crushed to death. This does not exclude taking damage from being smacked with an object.
 * It may be possible for the Flood to corrupt a Monitor as seen in Halo 2 in the case of the 2401 Penitent Tangent.
 * The Forge monitors have purple colored "eyes" this could mean that monitors all have different colors.
 * Mendicant Bias is never actually seen and neither is Offensive Bias.