GLaDOS

GlaDOS is the sometime guide and sometime antagonist of the game Portal. She attends Chell as she progresses through the Aperture Science test course, issuing instruction in the use of the Portal Gun and offering oblique and occasionally sinister advice and warnings. Her smooth female voice, issued through a PA system which pervades the whole of Aperture Science labs, is the only outward face of the organisation the player is ever aware of, or allowed to be aware of. It is not obvious who or what GLaDOS is, and what her actual role is at Aperture, until the very end of the game.

Appearance
GLaDOS represents Aperture Science, and guides the player from their chamber into and through the test course. It swiftly becomes obvious that despite her polite and equable tones GLaDOS is neither particularly bothered what happens to the player, nor entirely rational. She frequently lies about such concerns as the deadliness of acid pits, and also has a fixation with cake, which she insists will be served after the test is completed. She presents this and the bewildering and dangerous tasks the player is forced to perform as common procedure at Aperture. GLaDOS is also prone to vocal malfunction, often blotting out important pieces of information in bursts of static.



Confrontation
At the end of the test course, it becomes apparent that GLaDOS never intended to let the player leave the labs alive, a fact which she had actually been making clear all along. When Chell escapes through the use of the Portal Gun, GLaDOS's behavior starts to become alarmingly erratic. As Chell advances through abandoned labs and the industrial areas of Aperture, GLaDOS demands then pleads with the player to turn back, maintaining that cake will be served if Chell just stops behaving badly.

Eventually GLaDOS is discovered to be the "Genetic Lifeform and Disk Operating System", a huge supercomputer which is now apparently the only occupant of Aperture Science Enrichment Center. A red phone was installed in the central chamber which GLaDOS occupies to be used as a warning system should she turn rogue; this has, for whatever reason, not worked. There is some suggestion that GLaDOS has murdered the former human incumbents through the use of a neuro-toxin, which after the player destroys her morality program she gleefully turns on Chell. However, thanks to the appearance of a malfunctioning Rocket Sentry after the first "eye" is destroyed, Chell is able to redirect the fired rockets and eventually destroy GLaDOS by knocking off and incinerating the rest of her eyes.

The eyes are programs, and are in order of incineration: Morality, Curiosity, Cake and Anger.

At the game's end, a cutscene reveals many more of GLaDOS's eyes waking up in a dark closet, and during the credits sequence, GLaDOS can be heard singing that she is Still Alive.

Within the Half-Life 2 Universe
While describing the installation of the Morality Chip, GLaDOS mentions her previous flooding of the facility with Neurotoxin. When she makes this reference, her data screens briefly show the Black Mesa logo. This may imply that GLaDOS was somehow compromised by Black Mesa in order to sabotage Aperture Science, Inc. The rivalry between Black Mesa and Aperture Science is show in a slide show presentation that is visible in meeting rooms in the Portal game, as well as in the ending song where GLaDOS mockingly suggests Chell could get help from Black Mesa.

Towards the end of the game GLaDOS makes several references to the world outside Aperture Science. She says "much has changed" since Chell last saw it, that she is the only thing "keeping them from us", and Chell would find death preferable to what is currently going on outside. This seems to reference the Combine invasion of Earth, which places the events of Portal approximately concurrent to those of Half-Life 2; however, so characteristically vague are GLaDOS's words that she could be referencing something completely different, or indeed making things up.

Valve have stated that they deliberately kept this and GLaDOS's fate ambiguous, because they are as yet undecided as to how or whether to tie future Portal releases into the Half-Life series.

Trivia

 * GLaDOS is voiced by Ellen McLain.


 * GLaDOS's "Anger Sphere" is voiced by Mike Patton, lead singer of band Faith No More.


 * GLaDOS is more than slightly reminiscent of Hal 9000, the murderous sentient computer of 2001: A Space Odyssey.