Cortana

Cortana, UNSC Artificial intelligence (SN: CTN 0452-9), is a smart artificial intelligence construct. She was one of the most important figures in the Human-Covenant war, and was also John-117's partner in various combat missions as well as serving as the AI for the Halcyon-class light cruiser - UNSC Pillar of Autumn, Orbital Defense Platform - Cairo Station Charon-class light frigate - UNSC Forward Unto Dawn, and Stalwart-class light frigate UNSC In Amber Clad. In addition, she held vital data pertaining to the Halos, including the Activation Index from Installation 04. As Cortana is an AI, she has no physical body. She can communicate through comm systems and project a holographic image of herself from appropriate projectors, such as Holotanks. Her chosen avatar appears to be a naked female human, roughly in her early twenties, with purplish/bluish skin, shoulder length purplish/bluish hair cut shorter at the back, and blue symbols scrolling down her body. Cortana is said to resemble her creator, Dr. Catherine Halsey as a young woman, with a similar attitude "only unchecked by military and social protocol." Dr. Halsey says that Cortana looks somewhat like Miranda Keyes. By The Reclamation, Cortana had created a physical body for herself. She changed her face as well and her body appears as though she were wearing a circuitry-laced skin-tight suit with layered padding. When in a different emotional state, Cortana usually changes colors. This was especially noticeable in Halo: Combat Evolved, but less so in Halo 2 and Halo 3. Only in specific instances did she produce the color-changing effect. One instance of this was right before John-117 rescued her. Bungie took a fair of amount of artistic freedom in the evolution of her appearance throughout the Halo trilogy, noticeably from Halo: Combat Evolved to Halo 2. She had longer hair, a more-realistic humanoid figure, a much more feminine appearance, and a slightly different shade of purple. In Halo 3, she became slightly bluer and again her face, hair, and body were changed to look more feminine and realistic. In Halo: Combat Evolved Anniversary, she has her Halo 3 appearance. In Halo 4, she had darker, more opaque and realistic hair. Her facial structure had noticeably changed, her figure had become considerably more curvacious, and she gained better defined fingers and toes. The circuit-pattern mapping over her body changes between every game as well. Cortana had a witty and playful personality and a small sense of cryptic humor laced with some sarcasm. She had neither arrogance nor false modesty about her immense capabilities, and her statements about her abilities have an objective perspective that human beings typically cannot achieve. She did get bored often and easily. In fact, it is said that seven seconds of inactivity for an AI is excruciating. Cortana seemed to share some of her creator's memories, thoughts, opinions, and even values. When she was asked by Dr. Halsey to pick a "carrier," Cortana chose John-117 for his neural compatibility and his "luck." A similar reason used by Halsey for her choice, too. She was not only a facsimile of Dr. Halsey's mind, but also a replica of her physical form, albeit at a younger age.