SHODAN is the main antagonist of the video game series System Shock.

SHODAN - or Sentient Hyper-Optimized Data Access Network - started out as the artificial intelligence of the game's location, space station Citadel. The game's protagonist was forced to, at gunpoint, remove SHODAN's ethical restrictions, an act that started a process that eventually resulted in the AI going crazy, seizing control of the station's systems, robots and considerable defenses, and either slaughtering the whole staff of the station or converting them into mutants and cyborgs. With, of course, one sole exception.

Although as a cybernetic entity SHODAN has no conventional biological needs nor traditional gender identity, and in the disc version of the game it is referred to either as an it or a he, referring to SHODAN as a he while speaking to a System Shock fan is in all likelihood a serious faux pas. SHODAN manifests herself as a green and/or grey female cybernetic face that usually wears a malevolent expression, and speaks (in the CD version) with a voice that has been described as "oscillating between Alice in Wonderland and the Wicked Witch of the West." SHODAN is given voice by former Tribe keyboardist and vocalist, Terri Brosius.

The struggle against SHODAN is widely held to be one of the most personal ones in the history of video games, which no doubt contributes to the already considerable immersion factor of the game. Basically omnipresent in Citadel station, SHODAN watches from security cameras, stares out of screens and monitors, sends threats and snide messages and cuts off communications from friendly sources. Though it has a small army to command, SHODAN has no actual physical power to wield and as such thwarting more than one of its schemes has to be done with the AI's screams and threats in the background.

SHODAN's motivation stems from her perception that she is superior to the human race to the point that she considers herself divine. Henceforth, she feels that it is her right to either rule humanity or wipe it out, replacing it with a new form of life of her own creation. From this comes a extreme sense of arrogance and impatience with human beings, often referring to individuals as "Irritant" or "Insect."

Much of SHODAN can be summed up by the AI's most well known quote, to which text definitely doesn't do justice. It goes as follows: "Lo-lo-look at you, Hacker. A pa-pa-pathetic creature of meat and bone, panting and sweating as you ru-run through my corridors-s. H-h-how can you challenge a perfect, immortal machine?" - SHODAN.ogg to download a 109 kilobyte Vorbis audio sample.

SHODAN returned from her apparent defeat on Citadel Station aboard the starship Von Braun during the events of System Shock 2.