Cortana is a fictional character in the Halo Universe, and is an Artificial Intelligence, often seen along Master Chief.
Cortana was initially created by Bungie, a video game developer, for their first person shooter sci-fi epic, Halo: Combat Evolved. The game experienced such a success that the franchise branched out into other areas. Initially it started out as novels detailing the events around the Halo: Combat Evolved video game. Each one detailing the Cortana’s life from the earliest days of her conception to the events that led up to the first game’s sequel: Halo 2. During the success of Halo 2 Bungie released a graphic novel in partnership with Marvel comics. At that point the Cortana began making her appearances in comics.
Major Story Arcs
Halo: The Ringworld, the Moniter and the Flood
When the ship was crippled during a battle with a superior Covenant fleet the Captain, a decorated war
hero by the name of Keyes, crashed the ship on a strange ring world. After several skirmishes with Covenant forces Cortana discovered that the ring world was called Halo and was of religious significance to the Covenant. After the release of the Flood, the Chief was recruited by a robotic entity know as 343 Guilty Spark to activate Halo and destroy the parasitic life form. Guilty Spark also told the Master Chief that he was the Reclaimer, son of the Forerunners. He was prophesied to activate the ring. The Chief quickly discarded his remarks. What he failed to mention was that activating the ring would wipe out all sentient life in the universe in order to prevent the flood from spreading. Fortunately Cortana managed to stop John and together they decided to stop Guilty Spark. After tearing the command codes out of a Flood infected Captain Keyes they flew to the Pillar of Autumn's crash site and overloaded its engines. Destroying the ring and the Covenant ground forces.
Halo 2: The Battle of New Mombassa, the Second Ring and High Charity
Master Chief and Cortana captured a Covenant ship and rescued the survivors of the Spartan project on Reach before heading back to Earth. Here they were attacked by the Covenant Prophet of Regret, who had followed the instructions of a sacred prophecy and came to Earth looking for Forerunner artifacts, unaware that it was the human home world. After a short but bloody battle, in orbit and on the surface, the Prophet performed a slip space jump in the mega-city of New Mombassa, and disappeared, closely followed by the In Amber Clad with the Chief on board. When the ship dropped out of slip space it quickly became clear that the Prophet had discovered another Halo. The Master Chief went into action on the ring worlds surface to find and kill the Prophet while Miranda Keyes, Captain Keyes' daughter, tried to prevent its activation by getting to the Index before the Covenant.
The Chief was successful in his mission but was knocked unconscious when a Covenant ship glassed the area in an attempt to kill him. Miranda on the other hand was captured when the Arbiter, a Covenant holy warrior, arrived to claim the index. The Chief was sent to find the Index at the Covenant city of High Charity by Gravemind, the hive controlling mind of the Flood. Meanwhile, the Covenant were under the misconception that activating the Ring would ascend them to the next plane of existence. The Prophet escaped on a Forerunner ship, heading for Earth and the Chief followed, stowed away on the massive vessel known as the Dreadnaught, a sacred relic to the Covenant that powered High Charity. Unfortunately he was forced to leave Cortana behind as a safe guard against the Flood taking control of ships capable of slip space travel. He promised to return for her but she remained skeptical. Right before he went Cortana said to him, "Don't make a girl a promise when you know you can't keep it." When he is asked what he is doing on a Forerunner ship, Master Chief replies that his is going to "Finish the fight."
Halo 3: The Battle of Voi, the Ark Portal and the Replacement Ring
After being captured on board the Prophet of Truth's ship and subsequently escaping. The Chief
escaped by jumping off the ship and crashed landed somewhere within a forest near the ruins of New Mombassa. He then is found by Sergent Johnson and his men. They are then followed by the cloaked Arbiter when the Chief is about to shoot him the Johnson stopped him. The Chief fought in the Battle of Voi, clearing the way for an aerial assault on the Prophets fleet. Which had been busy excavating something under the African desert. As the human ships attacked a massive portal opened above the ground, through which the diminished Covenant fleet fled. After the arrival of a flood infected ship containing a message from Cortana landed in the area, the Master Chief was forced to once again ally himself with 343 Guilty Spark. In her message Cortana said that the portal lead to another Forerunner installation called the Ark, which would allow Truth to activate all seven of the Halo rings dotted throughout the universe. Now working with the Arbiter who's race had seceded from the Covenant, the Chief and his allies followed Truth through the portal and engaged his troops. Victorious in all engagements, the Chief was able to stop Truth from activating the rings, allowing the Arbiter to kill him. Unfortunately they arrived too late to save Miranda Keyes, who was shot in the back by Truth while she tried to kill herself and Sergeant Johnson. Since only a human could activate the Ark, they had both been captured to do so. The Gravemind chose this moment to make its play and betrayed the Chief, trying to infect him and the Arbiter. After fighting his way into High Charity, which had now become a Flood colony, the Master Chief rescued Cortana and started to implement a plan to stop the Flood. Using the index from the first Halo ring, the Chief activated an incomplete ring, that would destroy the Ark and the Flood with it. However Guilty Spark went rampant, killing Johnson, when he realized that the plan would destroy the under construction Halo. The Master Chief destroyed him and tried to help Johnson, but it was too late. The old sergeant told John,
"Send me out, with a bang."
Before passing him Cortana's micro chip. The two activated halo and escaped in the ship that had brought them to the Ark. Unfortunately the portal collapsed while they were going through it and left them stranded, beyond the blast radius of Halo but in the gulf of empty space beyond the galaxy. Cortana predicted that it would be several years before they were found and so the Master Chief froze himself, telling her:
"Wake me up when you need me".
Halo 4 : The Beginning of the Reclaimer Saga
Halo 4 is the seventh video game in the Halo franchise, and is the first Halo video game developed by 343 Industries. It is also the direct sequel to the mega-blockbuster : Halo 3.
Halo 4 takes place in 2557, four years after the main events of Halo 3. Master Chief is awakened by Cortana aboard theForward Unto Dawn, and battles "Storm" Covenant (Covenant species who oppose the peace between Humanity and theCovenant/Elites. At first, Cortana and Master Chief suspect that they were found, then attacked by a salvage rogue Covenant aircraft/frigate, but it turns out that they are an entire fleet around the Forerunner planet. The ships temporarily deactivate their shields in order to send nukes. Master Chief uses this to his advantage to manually activate a nuke and take down the aircraft. However, the Forerunner's main gate opens (the Gravity Well) and sucks the ships, as well as John, into the abyss. This also marks the first major indication where Cortana is malfunctioning due to her "rampancy", or having "lived" as an Artificial Intelligence far longer than intended too. It is revealed that Cortana has lasted 8 years, where as all normal A.I last only 7 years.
With Cortana's "rampancy" acknowledged, Master Chief suggests a plan to find a ship to Earth, find Hasley, and fix Cortana's "rampancy". Cortana disagrees at first, and remarks that John "shouldn't tell a girl a promise he cannot keep", but later on says that this method may work since she is the only A.I to have been created through actual flesh tissue/DNA samples. Master Chief then finds a Warthog which miraculously survived the wreckage, and drives it deeper inito Requiem, the planet, or rather Shield World, they are on. Cortana then picks up an unknown signal and suggests that John follows it. They encounter more Storm Covenant forces, and even Sentinals protecting the Shield World, although they do not attack Master Chief. John then activates the "Cartographer" and finds that the mysterious signal is somewhere near the Shield World's core. Cortana opens a portal for quick access, and they then have their first encounter with Promethean Knights.
After being teleported closer to the signal it is revealed the signal is from the UNSC Infinity asking for help. A satellite near the center of the planet is blocking the signal, where two jamming towers are boosting the signal blocking device's power, Cortana suggests that the taking these jamming towers down to receive the whole signal. After going through a nearby portal and defeating several groups of the unknown enemy, which the only intelligence Cortana is able to get on them is the word "Promethean" and that they appear to be more advanced combat A.I's than Sentinels taking down the first tower. It is revealed the Covenant is very interested in finding something inside the core. After the second tower is downed the full signal of the UNSC Infinity is received, which states the crew is after a Relic of great importance located in the center of Requiem. Fighting his way to the center of the Satellite the pair discover a spherical object inside the satellite which is from where the signal is originating. After attempting to stop the signal the sphere comes close to the chief's location where part of the sphere comes out of the bottom. A sole figure is seen on the same Forerunner, sphere-like vehicle coming out of the bottom. The unknown figure reveals himself to be The Didact, and handily defeats the Master Chief before declaring that his people, The Forerunners themselves, are returning to the Galaxy after thousands of years, and he remarks on how Humanity must still be weak, as the Covenant do not answer to Humanity.
John manages to escape the Didact to search for the Infinity, which has entered the planet. The Didact also searches for the Infinity, however, the two take different rountes. After fighting off many Prometheans and Covenant (who have joined forces), he finds Commander Thomas Lasky and some other marines. Cheif clears an LZ for a Pelican to pick them up, and is transported to the Infinity, where he fights off waves of Covenant. Then, he is introduced to Captain Andrew del Rio and Commander Palmer. Palmer, Lasky, and the Chief are sent on a mission to attack the Didact, and are given a Mammoth. After destroying many Covenant vehicles, including a Litch, the mission brings John inside what is assumed to be a trap. It turns out not to be when John and Cortana are seperately taken by the Librarian, who explains that the Prometheans were once Humans, and how the Didact is looking to escape Requiem and find the Composer, which will allow him to take over the galaxy. She helps to accelerate Chief's 'evolutuion' so that he could survive the Composer. Once John and Cortana are reunited, they proceed outside of the Forerunner structures, where they attempt (and fail) to destroy the Didact. They are returned to the Infinity, where del Rio orders them to leave Requiem. Cortana and John attempt to convince him otherwise, but the Captain orders thet Cortana be decommisioned due to rampancy. Upon Chief's refusal to hand her over, he orders both Palmer and Lasky to arrest him, but neither of them move. With Lasky's assistance, John escapes the Infinity before it leaves, and attempts to destroy the Didact, once and for all. However, he is unsuccesful, and hides inside a Litch to follow the Didact into slipspace.
He, along with the Didact and a Covenant fleet, arrive at Halo Instillation 03, where the enemies immediately attack a UNSC science facility orbiting the Halo, which has the Composer in it. After fighting his way inside, John agrees with some professors there and grabs a bomb to attempt to destroy the Composer. Unfortunately, he is too late, and the Composer is fired and kills all on the base aside from him. He takes a Broadsword to follow the Didact to Earth, where he is assisted by the Infinity, wihch is now controlled by Commander Lasky, in getting inside. There, the Didact firest the Composer, and extermination of Humanity begins in New Phoenix. In order to bring down the Didact's shields, Cortana clones her rampant personalities to overload the system. John places her chip in a holopedestal, but it is destroyed, and she is brought into the Composer's system. She manages to weakly communicate with the Chief before assisting him in killing the Didact and destroying the Composer.
Powers & Abilities
Although Cortana herself cannot physically attack of defend someone, she can hack into the toughest security systems, can even tamper with Forerunner controls, and take over entire Covenant and UNSC Frigates. She is also unique among other Artificial Intelligence(s) because she was produced through actual living tissue/DNA (of Hasley's). Cortana is extremely smart and can process data immensely fast. She can multi-task and decode messages, and can be inserted into devices and structures, as she is inside a chip. Master Chief can carry her inside his head via a chip slot in the back of his helmet. He can insert her in structures/devices and then retrieve her inside his helmet. However, it is shown that Cortana, after 7-8 years (which is above the life span of an average A.I) will slowly start to go "rampant", or think herself to death (in which happened in Halo 4).