Monitor (Sarath)

Monitor was an artificial intelligence on the planet Sarath.

History
When his existence began, Monitor was an AI program created to help city officials coordinate and control the city of Arkhaven, one of the largest cities on Sarath. Although he might have been content to exist in this manner for centuries as he obeyed his programming, Monitor’s purpose began to change when an asteroid impact damaged Sarath’s moon, leaving the moon in a gradually descending orbit that would inevitably culminate in it striking Sarath and eliminating all life on the planet. As Professor Jessen, one of Arkhaven’s leading scientists, began work to construct the Ship, a massive rocket that should be capable of taking the surviving population of Arkhaven to Mirath, the next planet in the system, the city’s officials found themselves facing a massive influx of refugees attempting to gain access to the Ship.

This crisis came to a head when the city was attacked by the Taklarians, forcing them into a brief but devastating war that resulted in Arkhaven being reduced to around eight hundred thousand people from a population of over five million, although the Taklarian ship was destroyed. During this period of conflict, matters with the Ship began to become increasingly complicated. Due to Professor Jessen having lacked the necessary funding to do his research into rocket construction properly before the moon began to fall, he had made some errors in his earlier calculations, and had incorrectly calculated the power of the engine he could create. With the Professor only able to produce an engine capable of producing half the power required at best, construction on the Ship continued to provide a symbol to keep the population calm while the Functionary class - those responsible for the Ship’s construction - discreetly chose a group from their class who they felt could be trusted to travel to Mirath in the lunar lander, the ship that would have taken passengers from the Ship to Mirath when they reached the city, the lander being the only vessel possessing sufficient hull shielding to survive the debris that it would encounter. To further limit riots a camp was established for the NC2s - Non-Citizen, Non-Conformist, referring to people from outside Arkhaven or those who caused trouble in the city -, the threat of the camp limiting the possibility of rebellion as the NC2s would be left behind when the Ship left.

With the development of this plan, Monitor began to subtly take independent action; while he could have survived if the Ship had been in working order, with only the five hundred or so people who could be carried in the Lander, the population would regress to a low-technology level for some time, meaning that Monitor would ‘die’ as parts of his systems decayed without the ability to repair them. This plan began when Monitor inspired by Mayor Draad’s plan to make the city appear more populated than it was after the Taklarians’ attacks by illuminating hollowed damaged buildings and sending out cars filled with dummies; with Arkhavian medical technology occasionally relying on putting people in stasis when they faced imminent death until an effective treatment could be found, Monitor was able to secretly remove the people from the stasis tubes while they were concealed from the rest of the hospital - not violating his programming as they were technically already dead - and replacing them with convincing android duplicates, creating a secret group of ‘Trojan Horses’ that Monitor could use to infiltrate and control the final evacuation to secure his own existence.

However, Monitor’s plans were jeopardised approximately a month before Zero Day - the day that the moon would hit Sarath - when the TARDIS arrived on the planet, although the TARDIS crew were separated when the building that they had materialised on top of was hit by a meteor strike, Barbara being lost in the sewers under the building while Susan was taken to hospital and the First Doctor and Ian sent to the NC2 camp. While Susan was in hospital, she was replaced by one of Monitor’s androids, but since she had actually been merely entering a healing coma rather than actually dying she regained consciousness before her body was cremated and managed to escape. Meanwhile, The Doctor and Ian were able to tell their story to one of the wardens of the NC2 camp, the discovery of the TARDIS prompting him to consider the possibility that their story was true (Although The Doctor was unable to show them the interior as Barbara had the only available key), Draad offering The Doctor access to the city’s equipment to create a new key for the TARDIS in exchange for his advice in the final stages of the ship’s construction.

Although The Doctor quickly deduced the truth about the Ship after he was allowed a closer look at it - allowing him to make a few quick calculations based on mass and power requirements to deduce that the Ship lacked the power to get off the ground -, he was forced to continue his work out of a lack of anything else to do. The situation became even more complicated when a group of Church functionaries abducted Susan to question her about her religious beliefs, fearing that The Doctor and his companions might introduce doubt in their gods, resulting in the accidental death of the Church’s leader during the rescue - they were putting Susan through a ‘trial by water’ in a leisure club and the bishop fell into the water and was dragged down by his robes - and the discovery of this Susan’s android nature. At the same time, the real Susan and Barbara were reunited, only to be captured by the group of Functionaries responsible for developing the Lander to be used as an expendable labour force, having previously assisted in aiding NC2 escape efforts from the camp to capture the NC2s and use them for the same purpose.

Before The Doctor and Ian had time to consider what to do about the discovery of Susan’s true nature, the moon’s descent was accelerated when it was unexpectedly pulled apart by tidal stresses, resulting in Zero Day occurring over a month in advance. With The Doctor and Ian delaying their return to the Ship to continue their search for Susan and Barbara - during which they encountered the surviving NC2s, released from the camp when the warden refused to obey his orders to kill them -, they thus missed an attack on the ship mounted by the surviving Taklarians, Draad destroying the Ship after the Taklarians had boarded it. The Doctor was able to lead the NC2s to the Lander after deducing its most likely location, but the subsequent attempt to appeal to Draad was interrupted when Monitor finally revealed his true intentions - no longer required by his programming to obey Draad as Arkhaven no longer existed as a legal structure that would require a mayor (Cities required a thousand inhabitants to classify as such and Arkhaven now had around half that) -, taking direct control of his androids.

Fortunately, despite Monitor’s refusal to be controlled once again and the shock factor of the androids’ true natures, the addition of Susan’s android to the equation proved to be Monitor’s undoing. Since Monitor’s androids included duplicates of the templates’ brainwaves, Susan possessed an undefined but existent connection to her android, allowing her duplicate to resist Monitor’s influence and thus disrupt his connection to the other androids. Although Monitor refused to be controlled again, one of his androids - originally a security officer called Ben Lant who had helped The Doctor and his friends during their time in Arkhaven - regained enough memory of his human identity to destroy Monitor’s central databank, destroying Monitor once and for all. Although Monitor attempted to gain some measure of revenge by damaging the Lander’s control computer in his last moments, the android Susan was able to connect herself up to the system and take its place, The Doctor using an ‘escape pod’ from the TARDIS to provide the Lander with additional space without an increase in mass so that all of the survivors present could depart in the ship (PDA: City at World's End).