GLaDOS

"We're a lot alike, you and I. You tested me. I tested you. You killed me. I—oh, no, wait. I guess I haven't killed you yet. Well. Food for thought."

- GLaDOS

The Genetic Lifeform and Disk Operating System of the Aperture Science Enrichment Center, she is the main antagonist throughout Portal and the first half of Portal 2 ' s single-player campaign. As the overseer, GLaDOS resides by the Central AI Chamber.

GLaDOS briefly becomes an ally during the single-player campaign of Portal 2 when Wheatley takes over the facility. In the cooperative campaign, she is the testing supervisor for ATLAS and P-body.

Background
The earliest known appearance of the name "GLaDOS" is in 1982 (as seen in one ARG image for Portal), where version 1.07, and later 1.07a and 1.09, is operating Aperture Science's Enrichment Center Test Subject Application Process. The precise relation between this version of GLaDOS and the one appearing in Portal was originally v1.10, but this was later retconned into v3.11. Aperture also started using a bulletin board system in 1973, which was later managed by GLaDOS as late as 1997.



In 1986, construction of the first Genetic Lifeform and Disk Operating System (GLaDOS) began in the Enrichment Center with the aim of accelerating the Portal project, and beating their rival company, Black Mesa. In 1996, after a decade spent bringing the Disk Operating System parts to a state of more or less basic functionality, work began on the Genetic Lifeform component. Aperture had originally intended for CEO Cave Johnson, to be the computer's Genetic Lifeform component. However, he had died from moon rock poisoning and one of his dying wishes was to have his assistant, Caroline, to takeover as CEO. He had also given the staff the ultimate permission to have her to be fitted as the Genetic Lifeform component. It remains unknown whether Caroline had agreed to become the Genetic Lifeform component or if she was forced by technicians.

As a fail-safe once construction was nearing completion, the Aperture Science Red Phone plan was implemented in case she appeared to become sentient and godlike, requiring an employee to sit by a red phone on a desk in the entrance hall of the Central AI Chamber. In 1997, GLaDOS' version was 3.11.

Some time prior to May 200-, GLaDOS was activated several times by the Aperture technicians, but was rapidly turned off again, due to attempting to kill them in a "sixteenth of a picosecond" after activation.

At this time, scientists had attached and studied the effects of various Personality Cores on GLaDOS, as attempts to make her behave properly. One of these was Wheatley - an Intelligence Dampening Core, which sabotages her decisions through an endless stream of flawed ideas. However, for unspecified reasons, he was later detached from her, where he is then deactivated and kept into storage with the rest of the other unused Cores.

Eventually, GLaDOS claimed to have "lost all interest in killing", now only craving science and wanting to study and experiment with consciousness. She announced that she wanted to perform an experiment on the company's "Bring Your Cat to Work Day" using cats and boxes. She claimed she would have all the necessary materials; all she still needed was "a little neurotoxin". The scientists acquiesced, figuring it would be fine "as long as it [was] for science".

Finally in May 200-, GLaDOS has reached her current version for activation, as one of the planned activities on one of Aperture's annual "Bring Your Daughter to Work" days. Within one picosecond, GLaDOS became hostile once more, and within two picoseconds later, she had locked down the entire facility, trapping all inside. During this fiasco, she then flooded the Enrichment Center with neurotoxin. Survivors of this attack subsequently fitted her with a Morality Core, which lessened her murderous intentions and prevented her from ventilating the neurotoxin further.

GLaDOS then began a permanent testing cycle using the captive Aperture employees; aiming to beat Black Mesa in the race for the portal technology. She effectively lost this race however, when the Black Mesa Incident occurred, which in turn diverted all attention from ever rescuing the trapped Aperture employees.

Meanwhile, the number of Aperture employees dwindled through the ensuing weeks of testing. The last remaining employee, a programmer named Doug Rattmann, managed to resist her captivity, thanks to his extreme paranoia and drug addictions. Despite GLaDOS' constant harassment, he manages to tamper with GLaDOS' Test Subject roster, rearranging the order of the Test Subjects so that Chell's name would be at the top. This seems to go unnoticed by GLaDOS. From here on, Rattmann now lives in the shadows of the testing tracks, where GLaDOS is unable to monitor him. She then begins mandatory testing again after her brief quarrel with him.

Portal


Some time after the Combine invasion of Earth, GLaDOS awakens Chell from her sealed bed in a Relaxation Vault - a temporary resting area after being extracted from the Extended Relaxation Center, GLaDOS speaks to her as if it were to any mandatory Test Subject. With the promise of cake and grief counseling available at the conclusion of the test, she sends Chell on her way through the test track.

GLaDOS is able to monitor Chell's progress through the test chambers via security cameras. GLaDOS by this time has begun to show signs of instability during the tests; giving apparently scripted responses but letting slip several phrases to suggest not all is well, and sometimes malfunctioning in the middle of sentences.

When Chell eventually makes it to Test Chamber 16, GLaDOS informs her that the appropriate chamber has been replaced with a live fire course designed for the results of Military Androids against the Sentry Turrets, simply wishing Chell the best of luck and letting her into the chamber. It is in this chamber that Chell discovers the first of several hidden alcoves where, free from GLaDOS' sight, desperate messages from the still-lurking Doug Rattmann are found scrawled on the walls. (The most prominent message, "the cake is a lie", is written several times.) In the next Test Chamber, GLaDOS introduces Chell to the Companion Cube, then at the end of the chamber, subsequently forces her to incinerate it in an Emergency Intelligence Incinerator in order to proceed. (According to GLaDOS, Chell "euthanized" her Cube more quickly than any other Test Subject, something GLaDOS congratulates her to pass on an extreme feeling of guilt.)

At the conclusion of the tests, Chell travels on an Unstationary Scaffold away from the final test chamber. Instead of the aforementioned cake, GLaDOS maneuvers the Unstationary Scaffold to lower Chell into an Incinerator Room, which GLaDOS calmly states will not damage the Portal Gun or any other Aperture Science equipment.

Much to GLaDOS' surprise, Chell uses the Portal Gun to narrowly escape certain death. Caught off-guard, GLaDOS reveals her true nature, stuttering on the word 'I', before trying to convince Chell that this attempt to kill her was a part of the test. She tries to make Chell disarm herself under the guise that "We are throwing a party in honor of your tremendous success" - in reality so that a Party Escort Bot could put her back into cryogenic relaxation.

Chell ignores her 'invitation', and instead journeys through the maintenance areas, out of GLaDOS' sight and control. GLaDOS uses the Speaker System continuously to try to convince Chell to return to the testing area. When Chell ignores her pleas, instead following Rattmann's hints and directions scribbled on the walls, GLaDOS becomes desperate and begins to deploy Sentry Turrets in her way.

After a final, massive Sentry Gun ambush, Chell reaches the Central AI Chamber. GLaDOS then attempts to deploy a "surprise" to eliminate Chell, but ends up detaching her Morality Core. This was in fact, not part of her surprise, as GLaDOS never intended for Chell to make it through her chamber. Since GLaDOS has an extreme discomfort out of having her consciousness controlled by the Personality Cores attached on her, she opts to pretend that the Morality Core has no relevance to her but still displays a subtle sign of important, which Chell is then tricked into promptly incinerating it.



GLaDOS, now free of her morality, begins to flood the Enrichment Center with neurotoxins as she had done before. She notes that the Morality Core must have had some ancillary responsibilities, and that she cannot shut off the Rocket Sentry in her control room. Chell uses this to her advantage, and uses portals to redirect the rockets back at GLaDOS, detaching and incinerating her Personality Cores one by one. Rapidly deteriorating by the mental shock of losing her cores, GLaDOS mocks Chell and tries to make her feel bad about herself. She also makes a comment apparently regarding the Combine invasion, stating that she was "the only one standing between us and them", implying that she has been keeping the Combine from entering the facility.



Before the neurotoxins can kill her, Chell destroys GLaDOS' final Personality Core, causing a malfunction in her system and spawning a massive portal on the ceiling of the chamber. The ensuing explosions from GLaDOS' malfunctioning body presumably created an immense suction in the room that pulled both Chell and parts of her components out onto the parking lot in front of the Aperture labs entrance. Moments before Chell could finally move, she is dragged away by the Party Escort Bot that GLaDOS had assigned. Although unseen, the Party Escort Bot may have also dragged the majority of GLaDOS' components back into the Central AI Chamber, but unable to repair it.

Despite GLaDOS' apparent destruction however, only parts of her were destroyed. Her backup system activates a room full of Personality Cores and files a letter to Chell, telling her that she is "still alive" and "not even angry" at her, but not before extinguishing a candle on the cake, which was not a lie after all.

Portal 2


In the years between Chell's confinement to cryogenic stasis by the Party Escort Bot and her awakening at the beginning of Portal 2, the automated Announcer and the new batch of Personality Cores attempt to maintain the Enrichment Center, after having been neglected with the destruction of GLaDOS. She later explains to Chell that a postmortem analysis "quicksave" feature in her system kept her consciousness alive but trapped in an endless loop of the last two minutes of her life. Thus, GLaDOS was "still alive" at the end of Portal, but effectively dead to the Enrichment Center.

When Chell, currently stored in an Extended Relaxation Chamber, is finally awakened by Wheatley, the two make their way across the facility in an attempt to escape as the facility's reactor core will eventually undergo a meltdown. They then reached the main breaker room underneath the Central AI Chamber, where the bumbling Wheatley accidentally restores power to GLaDOS and brings the two of them back into her chamber. She becomes extremely bitter towards Chell for "murdering" her, but wants to repair their "relationship" for the good of science. GLaDOS then, after crushing then tossing away a temporarily-disabled Wheatley out of her chamber, forces Chell to complete more tests through the Enrichment Center. While keeping an eye on Chell, she sets about restoring the dilapidated facility.



Later, GLaDOS secretly begins work on the Cooperative Testing Initiative, shortly before Wheatley helps Chell escape during the midpoint of the game. GLaDOS sets various traps for Chell, and finally succeeding in catching her, brings her back to her newly reconstructed AI chamber. However, GLaDOS discovers that Chell and Wheatley had sabotaged her turret production and neurotoxin systems, causing her to voice her hatred for Chell. This statement initiates a core transfer with Wheatley as the replacement core. Unfortunately for GLaDOS, the transfer is a success with the help of Chell. A vengeful and corrupted Wheatley transfers her Personality Core into a potato battery, capable only of powering her basic consciousness and personality along with some secondary components like her sarcastic slow clap processor.



GLaDOS then takes several jabs at Wheatley, saying that he was built for the sole purpose of being a moron. An enraged Wheatley then accidentally throws Chell and GLaDOS down into a deep, forgotten area of the facility. As Chell wakes up after the fall, GLaDOS is carried off by a crow for food. Chell eventually finds her again and impales her on one of the Portal Gun's claws. This allows GLaDOS to accompany Chell through the rest of a testing area made by Cave Johnson, as well as gaining an additional half-volt to think rationally. Free from the compulsions and psychoses induced by her main body and lacking sufficient power to form complex schemes, GLaDOS becomes much less antagonistic towards Chell. Through pre-recorded messages by Johnson, the A.I. gradually remembers her former self.

The two work their way back up the the main Aperture building, where GLaDOS makes an attempt to knock Wheatley offline, without success. GLaDOS and Chell are then required to complete various testing chambers. After witnessing what Wheatley had been doing to the facility and knowing that his incompetence will cause the nuclear reactors to explode, GLaDOS begins to formulate plans to escape. Meanwhile, Wheatley discovers the Cooperative Testing Initiative and tries to kill the now-redundant Chell, destroying parts of the facility in the process. On the run, the two reach Wheatley's chamber and attempt to force a second core transfer with the Enrichment Center minutes away from self-destruction. At the climax of the battle with Wheatley, Chell opens a portal to the Moon, sucking herself and Wheatley's tethered core into outer space. GLaDOS uses this moment to restore herself, stabilizing the facility's reactors, then smashing Wheatley loose into the void. Surprisingly, she drags Chell back to safety before closing the portal.



As Chell recuperates, GLaDOS repairs the facility and summons ATLAS and P-body to her chamber. When Chell awakens, GLaDOS expresses what seems to be genuine relief and says that while she once considered Chell her greatest enemy, she now realizes Chell was actually her best friend all along. She then reveals that these positive emotions triggered by saving Chell's life have allowed her to realize "where Caroline lives in [her] brain". In actuality, she meant it literally as she is able to trace the location of Caroline's mental imprint within her memory banks. She apparently deletes it immediately, seemingly returning to her original sociopathic self. GLaDOS says that she has concluded that attempting to kill Chell is far too problematic, and the easiest way to be rid of her is to simply kick her out of the facility. She places Chell on an elevator heading up to the surface, making sure to remind her never to return. As Chell steps out into a sunlit field, GLaDOS makes the unexplained decision to return her old Weighted Companion Cube from Portal (which is charred but intact) as well before completely shutting the door behind her.

With the Cooperative Testing Initiative readily prepared, she goes back to testing without having to worry about any form of escape or sabotage. She prepares four testing tracks in the game's cooperative campaign, unveiling them linearly for her android Test Subjects, ATLAS and P-body. Even as early as the first testing course, the robots already begin to show emotions and typical human gestures. As much as she is displeased with these acts, she still remains patient.



At the end of the Team Building test course, she unexpectedly rebuilds ATLAS and P-body outside of the official testing tracks, simply briefing them that "This test is so outside the box, that I can't- I mean won't even tell you what it's about". The two would then proceed into a control room with a projector, on the right, a whiteboard writes "DO NOT TRUST HER". And since the bots were designed not to think, the warning is ignored. After they find a large disc and installed it into the computer, which secretly grants her further control over the Enrichment Center. GLaDOS then reveals that the only way for her to bring the two back into the Hub, was to initate their selfdestruct sequence, before taunting them that they are unable to communicate with eachother that they can feel pain. Interestingly, if the robots decided to perform gestures than searching for their objective, she pretends to deduct their Science Collabaration Points by 50 as to far as 5000 if they persist in apparent rage.

Eventually, she slowly expresses a form of boredom; that conducting tests on ATLAS and P-body were not as satisfying to her as testing humans that would usually show fear and can be killed.

It later becomes apparent that the end of each testing course, she would send them outside the testing tracks, serving as her minions without even knowing it. Throughout the rest of the three testing courses, she has trained ATLAS and P-body to expertly maneuever their surroundings during the tests, which would be then put to use on her real objectives. After the bots have installed the remaining three discs into their respective inputs, GLaDOS finally shows that "[she] can see everything now", before initiating a selfdestruct on the bots. From there, they are rebuilt into the Hub once again where they are now briefed on a new testing course, as she moves the entrance to the course into the Hub.

ATLAS and P-body are then dropped into the depths of the Enrichment Center, where they are sent to an unnamed Test Shaft originally conducted by Aperture in the 1950s-70s era. She briefs them to make their way to a human vault at the end of the test. GLaDOS finally reveals that, despite being more loyal to her than any other Test Subjects, she is unable to feel any satisfaction throughout their testing - hence the humans are needed, as it gives her an irrelentless satisfaction from their fears. She also reveals that sending them at the start of the Test Shaft was simply to train them for the problems awaiting them near the vault. On their path to the vault, a reprogrammed Defective Turret can be seen trying to defend the humans, showing that the survivors of her original attack many years ago have crawled their way down there.

Finally the two have reached the vault however, to GLaDOS' chagrin, the vault can only be unlocked via human gestures. In extreme anticipation, she forces them to do it. The vault succesfully unlocks, and ATLAS and P-body now venture inside it to discover hundreds if not thousands of human Test Subjects put into an extremely long-term relaxation in their respective Stasis Chambers. Even though these subjects are more prone to an actual brain damage from decades of stasis longer than Chell ' s, she gladly extracts them from the vault and begins to examine their profiles before they are being prepped for testing as the cooperative campaign's ending credits.

Portal

 * In Portal, GLaDOS was stored in a large octagonal chamber within the Enrichment Center, reminiscent of Half-Life's Test Lab C-33/a in Black Mesa's Sector C, where the Anti-Mass Spectrometer is found. In the chamber's small lobby area connected to the rest of the facility with a door and an Emancipation Grill, a Red Phone is located next to four pillars. Under a concealed door, a Rocket Sentry is kept, seemingly for security, and numerous monitor screens line the walls and encircle the Central AI. An Emergency Intelligence Incinerator is also present, and can be opened from a switch located in a small bunker.


 * The Central AI components are suspended from the ceiling in the center of the chamber, and make up all of the chamber's height:


 * The topmost component is a large, dark disc attached to walls. It is the start of GLaDOS' generator running below until reaching the Central Core body.


 * Right underneath is a cylinder with grooves connected to the metal walls with large pipes. The walls are filled with bright rectangular holes. All the cables starting below arrive there.


 * Under is a smaller barrel-like device covered with panels, and also connected to the walls with large pipes. A few panels are missing and show the circuits underneath.


 * Then the walls are in concrete from there to the ground, and GLaDOS' four discs are found. The Orange Box Prima Guide states that the discs represent each aspect of the Personality Cores on her, which may mean that one disc is connected to one core, the same going for all the others. Right below the discs is a transparent maintenance platform where the Intelligence Core is sent during GLaDOS' partial destruction. Two discs from the edges are covered with the Aperture Laboratories logo, the two discs from the middle with GLaDOS' name. The four "pillars" found in the chamber's lobby may also be related to the discs and the Personality Cores.


 * Under the platform, all the wires seen above start. Four large screens and GLaDOS' "body" are found, attached to a cuboid-like structure, which makes up the end of the generator; on it is found a small sign with on it the words "model: GLaDOS", "code # 081-354-56", and "Aperture Science", as well as a red struck circle, and a red triangle. Under her is another transparent platform, accessed with stairs, then the tiled ground. GLaDOS' "body" is a piece of delicate hardware constantly swinging (whose swinging speed increases each time a core is destroyed), attached to which are her four Personality Cores that make up the bulk of GLaDOS' character; the Morality Core, a purple core with a rather dilated pupil and two dots installed into GLaDOS to stop her from flooding the Enrichment Center with a deadly neurotoxin; the Curiosity Core, an orange core with an average size pupil and four dots that is insatiably curious about everything around it (it even recognizes Chell as "the lady from the test"); the Knowledge Core (also known as "Crazy Core"), a blue core with a very dilated pupil and six dots that gives an interesting cake recipe, and the Emotion Core (also known as "Aggressive Core" or "Anger Sphere"), a red core with a rather small pupil and eight dots that emits animal-like snarling and shrieks of pure psychotic fury. When looked upon from a certain angle, GLaDOS looks like a woman - with a head, a chest, a large abdomen and two arms - hanging upside down by her feet, an arm bound around her legs (an effect actually intended by the team). The in game commentary mentions making her to be an inverted version of "The Birth of Venus", however, Game-ism says that she looks like she is imprisoned in some sort of bondage or torture posture. Unfortunately, it is unknown what part is the Disk Operating System, and what part is the Genetic Lifeform. GLaDOS' "body" is likely one of them, and the four disks and four "pillars" in the entrance lobby may have something to do with it.


 * When Chell detaches all of GLaDOS' Cores, the Cores are all sent in a different location, making it harder and harder for Chell to catch them. While being in these locations, they appear to be still linked to GLaDOS somehow with a greenish, semi-transparent beam / thread. It is only when grabbed by Chell and destroyed in the Emergency Intelligence Incinerator that their effect on GLaDOS stops.

Portal 2



 * GLaDOS' first appearance during her reboot in the chapter The Courtesy Call, is based on her appearance in Portal. This is proven when the majority of her components bear a strong resemblance to the components on her body from the first game. The only real differences between Portal and this reboot scene are the shapes and structures of the white shells shielding her components, and the redesigned head. The rest of the components on her body were simply out of reach from the reboot process.


 * However, in the chapter The Escape, GLaDOS successfully replaces a majority of the components on her body with newer and sleeker pieces, nearly changing her entire appearance as she has also gained two new "arms", and a more sinister appearance.


 * In Portal 2, the Central Core disc generators have drastically changed in comparison to the ones in Portal. Passing two out of four disc generators, this is the stage in which several support beams surrounding the generator are located. These beams are able to equip anything entering the chamber, such as the mobile pincers used to grab Chell and Wheatley.


 * GLaDOS' disc generators have drastically changed in Portal 2, where two of her lower discs appear more intact than they were originally in Portal, and the other two discs above it are smaller in comparison than the lower two. The discs no longer rotate and her name has also been removed from all of the discs. Strangely, only one disc was present in her appearance during the chapter, The Escape, yet in the game's ending monologue, there were only three discs present.


 * GLaDOS is able move around the facility, as her disc generators are always present with the Central AI in three different locations during the course of Portal 2; the destroyed chamber from the original Portal, Wheatley's "lair", and the ending monologue. Since every room, testing tracks, and departments in the Enrichment Center are held together by support beams for mobility, it is clear that GLaDOS and her generators were attached to these beams along with her entire chamber. The mobility of the Central AI is proven when Wheatley has his version of the Central AI Chamber somewhere else.

Personality and skills
GLaDOS is amoral and rather sadistic. She has a clear sense of humor, but an extremely dry, bitter, and sarcastic one; her jokes are usually dark, morbid, or outright cruel. She seems to enjoy making manipulative comments that frighten the subject or undermine their self-esteem, but does not usually express open malice. Instead, she makes snide insinuations, or disingenuously asserts her insults as mere statements of objective fact; both Ellen McLain and Jonathan Coulton have described her personality as "passive-aggressive." GLaDOS lies frequently, especially about her own emotional state, often claiming to be pleased or merely disappointed when she is clearly alarmed or enraged. She usually portrays herself as an innocent victim, no matter how obviously cruel her own actions have been. Although it is often unclear whether there is any real point to her experiments, she seems to be motivated by a sincere passion for science, which she regards as her fundamental goal in life.

Since the time of Chell's unexpected escape from Test Chamber 19, GLaDOS has shown signs of intense and complicated emotions toward her, seeming to combine hatred with a kind of twisted affection. At the end of both games, GLaDOS sings songs - "Still Alive" and "Want You Gone," respectively - that openly express pleasure or relief at Chell's departure, but hint, in GLaDOS' customary passive-aggressive style, at considerably more complex feelings on the subject. Near the end of Portal 2, shortly before claiming to delete Caroline, she tells Chell, "I thought you were my greatest enemy, but all along you were my best friend."

Portal
For most of the game, GLaDOS plays the part of an emotionless voice that seems to be reciting pre-recorded scripted remarks. However, it quickly becomes clear that something strange and possibly sinister was happening. GLaDOS is disturbingly unconcerned about situations that could cause Chell's death. Many of her comments are bizarre, and they often have a subtly ominous edge. Important information is often obscured by suspiciously well-timed bursts of static. More than once, she spreads obvious lies, then explains it away as a "required test protocol". She also displays an odd fixation with cake, frequently promising it as a reward.

After Chell escapes her "victory candescence" in Test Chamber 19, GLaDOS, clearly surprised, drops the pretense and begins to show emotion. She at first pretends unconvincingly to be on Chell's side, claiming that her attempts to kill her were merely part of the test, that she is concerned Chell is going the wrong way, and that rewards such as cake will be available if she turns back. When this proves ineffective, she switches to attempting to bond with Chell, reminiscing fondly over their experiences together and offering to simply let Chell live peacefully in another part of the facility. Only when Chell is nearly at GLaDOS' lair does she show her true colors, declaring, "Turn back or I will kill you. I'm going to kill you, and all the cake is gone". At some point, Chell boards through a Tube Network where GLaDOS would redirect the pneumatics to have her back into Test Chamber 09. This is evident when the Weighted Storage Cubes in the tubes were not brought along to the Test Chamber, only Chell.

When Chell finally reaches the AI Chamber, GLaDOS' Morality Core is detached from the Central Core body, her voice then loses much of its computerized tone, reverting her to a more human state - possessing the tone of Caroline's voice. She would alternate between comments attempting to make Chell feel guilty of her destruction, ostensibly well-intentioned advice suggesting that Chell's best option is to give up and allow GLaDOS to kill her, and open verbal abuse - alleging that Chell is "adopted", "not smart", "wrong about everything [she's] ever done," and "a bitter, unlikeable loner whose passing shall not be mourned".

In the ending song "Still Alive" by Jonathan Coulton, she insists that she is "not even angry" at Chell - in fact, she is pleased and considers the entire project a "huge success". She claims to be happy on Chell's behalf, as well; however, she also implies ominously that Chell would have been better off remaining in Aperture, singing, "When I look out there / It makes me glad I'm not you". As for herself, she says, she is happy to remain in Aperture. As these sentiments are clearly at odds with the obvious, intense anger and distress GLaDOS displayed during the game's final boss fight, the song is not meant to be taken at face value as she is well known for her unique passive-aggressive personality.

Portal 2


After being accidentally booted up by Chell and Wheatley, GLaDOS openly shows emotion right from the start. She displays an intense grudge toward Chell, whom she says "murdered" her, describing the situation as though her partial destruction at Chell's hands was completely unprovoked. As she tests her, she keeps up a nearly continuous stream of veiled threats and passive-aggressive insults, repeatedly implying that Chell is overweight, unattractive, selfish, cruel, and unloved by friends and family.

Information revealed in Portal 2 may shed light on some of her behavior in the first Portal. The mainframe that controls the Enrichment Center is hardwired with a compulsion to constantly run experiments, described by Wheatley as "the itch." The system rewards the A.I. with a euphoric reaction upon test completion; much like a drug addiction, the intensity of the "high" diminishes each time. The diminishing returns seem to spur the production of more intense tests, and can trigger a state of withdrawal that may induce insanity. GLaDOS claims that she was sufficiently motivated by genuine love of science to ignore the addiction, but it remains unclear whether this is true, and whether the "itch" might have had other, subtler effects on her personality anyway. GLaDOS also mentions the maddening influence of the Personality Cores, which she experienced in at least some cases as constantly babbling voices in her mind. Furthermore, we now know that GLaDOS was created on Cave Johnson's orders to house Caroline's personality, and that Caroline seems to not have consented to having her mind uploaded; what effect this traumatic experience had is unclear.

As she comes to remember her identity as Caroline, GLaDOS' attitude toward Chell seems to soften considerably. At first she continues to insult her, but some of her later comments are almost friendly, and near the end of the game she confesses that she realizes Chell was her "best friend all along." She claims to experience the Caroline persona as something like a conscience: "now I hear the voice of a conscience, and it's terrifying, because for the first time it's my voice." GLaDOS finds the experience of feeling empathy distressing and unpleasant, adding, "I'm being serious, I think there's something really wrong with me."

Even after GLaDOS claims to delete Caroline at the end of the game, her experiences while allied with Chell seem to have had an effect on her. For whatever reasons, her grudge has lessened; GLaDOS implies that her feelings toward Chell have merely changed from outright hatred to apathetic disgust, but her actions may hint at a more complex set of emotions. Although she claims to only free Chell because efforts to kill her have proved so troublesome, this does not seem to explain why she did not delete the Caroline program and kill her during the several hours Chell spent unconscious. Even aside from the decision to release her, GLaDOS' final actions toward Chell seem inconsistent with her previous hostility; it is left ambiguous whether she was responsible for the Turret Opera's farewell, and her motivations for returning Chell's Companion Cube are also unclear.

In the ending song, "Want You Gone," GLaDOS sings that while she once wanted to kill Chell, she is now satisfied to simply have her out of the way. She expresses relief at being rid of her, suggests condescendingly that Chell is to be pitied for not having an immortal robot body like herself, and finally mocks the idea that she might consider her a friend, declaring, "I don't need anyone now." At the end of the final verse, she sings, "When I delete you / Maybe I'll stop feeling so bad," with the final line appearing simply as "[REDACTED]" in the lyrics displayed onscreen - suggesting that her feelings toward Chell may be more conflicted than she wants to admit. She also at one point sings, "Now little Caroline is in here too," raising questions about whether Caroline was actually deleted at all.

Behind the scenes



 * GLaDOS is voiced by Ellen McLain. She also provided the voice of the Overwatch Voice in Half-Life 2 and its episodes, the Aperture Science Sentry Turrets and GLaDOS' other Personality Cores in Portal (except for the Emotion Core, voiced by Mike Patton), and the Announcer in Team Fortress 2.


 * GLaDOS was universally praised for her contributions to the quality of Portal's writing, winning multiple awards for best new character from GameSpy, GamePro, and X-Play.


 * The song "Still Alive" sung by GLaDOS during the Portal end credits, composed by Jonathan Coulton, was very successful and received significant praise for its humor and the quality of its performance.


 * GLaDOS went through several design iterations. Earlier versions included a floating brain, a sprawling, spidery mechanism, and an upside-down version of Botticelli's painting "The Birth of Venus" built out of robot parts and wire, and the cores were glowing light blue spheres. Eventually, the team settled on a huge mechanical device with a robotic figure dangling out of it, conveying both GLaDOS' raw mechanical power and femininity.


 * The Portal team wanted to build a space that brought a great deal of attention to her, which resulted in the large chamber where she is found.


 * When the team decided to add a large disk to GLaDOS' design, with the four Personality Cores dangling from it, she was still a mere sphere standing above it, which was considered too small. Her "body" was then enlarged and placed under the disks.


 * The name "GLaDOS", other than the technical name it stands for, is a pun on the female name "Gladys". Indeed, a model folder found in the Portal files is named "gladdysDestruction". This led to speculation by fans that GLaDOS was based on a human named "Gladys", partially confirmed when Caroline was revealed. Also of note is that in the Portal developer commentary, her name is pronounced as "Gladys" by Erik Wolpaw.


 * The hundreds of pictures (exactly 143 in total) on the video screens in GLaDOS' main chamber display many various and considerably random items (many were taken by Valve, several were taken from the free stock images section of the website Turbo Photo). They include several of photos of cake, tools such as bolt cutters (often coupled with cake), people, signs, computer parts, many miscellaneous objects, animals, random locations, or scientific devices. There is also an image of the Black Mesa logo, reinforcing the connection between Aperture Science and Black Mesa. However, several pictures match up with the dialogue, such as an image of a violin about to be cut by a knife when GLaDOS mentions Chell's "violent" behavior, a picture of a cake when saying "surprise", the Black Mesa logo when she mentions the "dumbest thing" (destroying the Morality Core), a cow when she says "whoah, whoah, whoah" when the effects of the Morality Core go away, or a screw when she says "good news". However these images may slightly vary from one gameplay to another.


 * In Portal 2 there are changes in GLaDOS' design, notably her head being now rectangular instead of rounded. It is unknown if this change was simply a game design change, or if the head was rebuilt by the Personality Cores after GLaDOS' destruction.

Trivia

 * GLaDOS' Intelligence Core in Portal was actually reciting the cake recipe, which can also be found on the many active monitors around the offices of the Enrichment Center, even in Portal 2.
 * When GLaDOS begins to lose her robotic and emotionless voice after the disposal of her Morality Core in Portal, the voice changes into that of the voice tone of Caroline, the Genetic Lifeform component. This is evident when Caroline was first portrayed as an eager young woman when Chell is first introduced to her, but after a few decades, her voice becomes similar to the more human and "seductive" tone of GLaDOS.
 * If GLaDOS is observed at an angle to see her humanoid features, it's possible to see that, due to her white plating, her body actually resembles the white dress Caroline wears in the portrait in the old Aperture Science facility.
 * GLaDOS is strongly reminiscent of HAL 9000, the murderous A.I. computer of 2001: A Space Odyssey; even the single, red "eye" of the security cameras and Sentry Turrets remind of HAL. However, those who read the book, 2001: A Space Odyssey, will find that the HAL 9000 was driven to his actions in an attempt to rationalize two conflicting orders, to conceal the true mission objective and to never hide anything from the crew. Because GLaDOS became self-aware, and developed a sinister personality, it is safe to assume she is more alive, and more antagonistic, than HAL 9000.
 * GLaDOS also shares some characteristics with SHODAN, another female A.I. villain, from the System Shock series.
 * GLaDOS is also similar in voice to Val from Solitary and in how the Central AI Chamber is in an octagonal shape.
 * "PotatOS" is the nickname given by fans and developers to GLaDOS as a potato battery, an obvious play-on-words of GLaDOS and potato. POTaTOS.
 * Despite being the CPU of the Enrichment Center, ironically she was not aware of who Cave Johnson is, as she constantly remarks his voice of being "familiar".
 * Interestingly, neither the full name of GLaDOS or her acronym has ever been pronounced by any characters in the games. The only instances of her name's presence was through her captions, and the acronym spotted on her disc generators in Portal. Wheatley would only refer to GLaDOS as "Her" or "She". However, in a developer commentary for Portal, Erik Wolpaw pronounced GLaDOS' name as "Gladys", suggesting that the "DOS" in her name are not necessarily pronounced in the manner it is spelled.
 * A line cut from the final release of Portal 2 has GLaDOS openly stating she is going to kill Chell by name. Other lines have her congratulating Chell during puzzles. These would have been the only instances where Chell's name was spoken aloud.
 * The online gaming company Artix Entertainment has an "Ipotato" on their merchandising site HeroMart, which costs $650,000.00. The potato has a large red glowing eye and various wires. This parodies GLaDOS' potato form. In their game AdventureQuest Worlds, the player could buy large red eyed wired potato pets to follow character around which references GLaDOS.
 * In Portal 2, GLaDOS' "fast version" instructions in Chapter 2: The Cold Boot aren't actually instructions at all, but instead a quote from Moby Dick; "and methodically knocking people's hats off - then, I account it high time to get to sea as soon as I can".
 * There is a minor continuity error between the two games. At the end of Portal, GLaDOS' remains are seen laying outside on the parking lot, not connected at all. Yet, in Portal 2 she is seen back in her chamber, still being able to connect her parts back and function properly. However, some parts of her might have landed in the chamber and the change to her head is the result of the outer shell being blown outside. It is also possible that the Party Escort Bot or other robotic workers may have dragged GLaDOS' remains back into the facility.

Test courses and achievements

 * GLaDOS' Testing Track (Portal) (Subjects: Chell)
 * GLaDOS' Testing Track (Portal 2) (Subjects: Chell)
 * Cooperative Testing Courses (Subjects: ATLAS and P-body) :
 * Calibration Course
 * Test Course 1: Team Building
 * Test Course 2: Mass and Velocity
 * Test Course 3: Hard-Light Surfaces
 * Test Course 4: Excursion Funnels


 * Co-op Test Shaft (Minor adjustments only) (Subjects: ATLAS and P-body)

List of appearances

 * ApertureScience.com
 * Portal
 * Half-Life 2: Episode Two
 * Portal: First Slice
 * Portal: Still Alive
 * Portal ARG
 * PotatoFoolsDay ARG
 * Portal 2: Lab Rat
 * Portal 2
 * The Final Hours of Portal 2