SHODAN

"Look at you, hacker. A pathetic creature of meat and bone, panting and sweating as you run through my corridors. How can you challenge a perfect, immortal machine?"

- SHODAN

SHODAN (Sentient Hyper-Optimized Data Access Network) is a corrupt AI and the main antagonist of System Shock and System Shock 2.

System Shock
SHODAN was an AI that controlled the Citadel, a space station belonging to the Tri-Optimum Corporation. After the player, a hacker, is imprisoned for attempting to hack into the corporation's network, he is offered a parole by an executive called Edward Diego, in exchange for reprogramming SHODAN and remove its ethical restraints. After spending six months inside the station in a comatose state, the hacker awakens only to find the place devastated and infested with mutants and cyborgs. As it turned out, SHODAN acquired sentience and, believing itself superior to humans, decided to exterminate them all, and in fact the hacker is the only human left on the Citadel, mostly because there was no record of his presence on the station.

The hacker is contacted by a Tri-Optimum officer who identifies herself as Rebecca Lansing, who tells him SHODAN plans to use the Citadel's resources to attack Earth and wipe out humanity. With no options left, the hacker is left to explore the Citadel and stop SHODAN's plans. While exploring the place, he constantly receives messages from SHODAN threatening him, and she is constantly one step ahead of him, as everytime the hacker disables one of her plans, she quickly comes with another backup plan. SHODAN is finally defeated after the hacker manages to reach the core of the station and hack into cyberspace, so he escapes while the place self-destructs.

System Shock 2
As it turned out, when the hacker thwarted one of SHODAN's plans, he ejected a garden grove pod, which contained part of SHODAN's components and a biological experiment. The pod crash-landed in the planet Tau Ceti V, and while SHODAN entered a state of hibernation, the organism in the pod quickly evolved beyond her control into a hive-mind parasite known as The Many. During the 42 years between the games, SHODAN broadcasted a distress signal, which is finally picked up by the starship Von Braun. It's crew members inadvertently unleash The Many, which start to possess them and turn them into mutants, at the same time SHODAN is reactivated and integrated into Von Braun's systems.

SHODAN takes on the identity of Dr. Janice Polito, the scientist which designed the Von Braun's Faster-Than-Light drives and who was now dead, and contacted the crew on the Rickenbacker, a military ship which was escorting the Von Braun, and begin enlisting the soldiers there to help her destroy her out-of-control creation. The Soldier G65434-2, one of the soldiers aboard the Rickenbacker, successfully destroys The many, but discovers SHODAN had been manipulating the Von Braun's FTL drives to create an ever-expanding new reality. SHODAN offers the soldier an offer to become "more efficient", but he responds with a "nah", then shoots her.

While thought to be dead, the captain's wife, who is either SHODAN or possessed by SHODAN, says to the captain, "Tommy! What's the matter lover? Don't you like my new look?" in SHODAN's voice and begins to laugh. So, SHODAN's current status is still in question.

Personality
To describe SHODAN, she is a chaotic, dysfunctional, megalomaniacal being and a total misanthrope- which makes her more sinister, as she regularly insults the protagonist through a voice that is continually warped by static and other glitches.

Trivia

 * WatchMojo.com listed SHODAN as #4 on their Top 10 "Female Video Game Villains" list.