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"Okay. Look. We both said a lot of things that you're going to regret. But I think we can put our differences behind us. For science. You monster."

GLaDOS (Genetic Lifeform and Disk Operating System) is an artificial intelligence created by Aperture Science, and the primary antagonist of the Portal series. She is the main antagonist throughout Portal and the first half of Portal 2's single-player campaign. As the overseer and highest of authorities of the Enrichment Center, GLaDOS resides in the Central AI Chamber.

GLaDOS briefly becomes an ally to Chell during the second half of the singleplayer campaign of Portal 2 after Wheatley takes over the facility. In the cooperative campaign, she is the testing supervisor for ATLAS and P-body.



The idea for GLaDOS came to Cave Johnson in 1982 during his final days. He wanted to "store a man's intelligence" into a computer in order to beat his rival Black Mesa and oversee his company after his death.

Cave caroline 70s

Portrait of Aperture CEO Cave Johnson with Caroline at his side.

In 1986, construction of the first iteration of GLaDOS began in the Enrichment Center with the aim of accelerating the Portal project, and beating their rival company, beans Black Mesa. A prototype chassis for GLaDOS was constructed in 1989, but was subsequently abandoned. 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.[1]consciousness could be uploaded, he left instructions that his assistant Caroline should be fitted as the Genetic Lifeform component so that she would be able to run Aperture in perpetuity after his death. However, it remains unknown whether Caroline agreed to be uploaded into the Genetic lifeform component or if she was forced by technicians. Unused audio files make it clear that the choice wasn't hers.

Once construction was nearing completion, the Aperture Science Red Phone plan was implemented as a fail-safe in case she appeared to become hostile and dangerous, requiring an employee to sit by a red phone on a desk in the entrance hall of the Central AI Chamber.[3]

Prior to May 200-, GLaDOS was activated several times by Aperture technicians, each time being quickly turned off after trying to kill them within "one-tenth of a picosecond" after activation.[4] Undaunted, the scientists began attempts to alter GLaDOS' personality and curb her murderous tendencies by adding various Personality Cores to her system. Several of these cores were deactivated and placed in storage at some point; one of these cores was Wheatley, Portal 2's sidekick turning antagonist, who was later re-purposed to the task of tending to humans in the Extended Relaxation Center.

After being fitted with a Morality Core, 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 Daughter 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 was activated as one of the planned activities on Aperture's "Bring Your Cat to Work Day". GLaDOS became hostile once more, and within two picoseconds she had locked down the entire facility, trapping all inside and flooding the facility with neurotoxin.

GLaDOS then began a permanent testing cycle using the captive Aperture employees, aiming to beat Black Mesa in the race for the portal technology. However, shortly after, she effectively won this race when the Black Mesa Incident occurred, destroying the competitor's entire facility, which in turn diverted all attention from rescuing the trapped Aperture employees.[1][2]

Meanwhile, the number of Aperture employees dwindled through the ensuing weeks of testing. The last surviving employee, a schizophrenic programmer named Doug Rattmann, managed to avoid captivity as a result of his paranoia. Evading GLaDOS' constant attempts to capture him, he managed to gain access to her Test Subject personnel files and research the psychological profiles of rejected candidates, discovering a woman named Chell who was rejected for testing due to extraordinary tenacity. Hoping Chell's stubborn determination might allow her to defeat GLaDOS, Rattmann tampered with the Test Subject roster, rearranging the order so that Chell's name was at the top. This seemed to go unnoticed by GLaDOS. From this point on, Rattmann hid in unused portions of the facility, where GLaDOS was unable to monitor him. She then resumed mandatory testing.



Testchmb 05

Test Chamber 05 during Chell's tests.

Some time after the neurotoxin attack, GLaDOS awakens Chell from her sealed bed in a Relaxation Vault. Promising cake and grief counseling upon the completion of testing, she sends Chell into the test track.

GLaDOS is able to monitor Chell's progress through the test chambers via security cameras. She provides instructions and encouragement but is careful to address Chell impersonally, giving the impression that she is merely a non-sentient voice programmed to provide pre-recorded, scripted responses. However, she seems unable to resist toying with Chell by making bizarre and often sinister comments. On several occasions, she seems to malfunction at suspiciously convenient points in mid-sentence, obscuring important information. These signs of instability begin early on, and become increasingly obvious as Chell proceeds through the test chambers.

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 (which are not mentioned anywhere else) against the Sentry Turrets, 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, hidden from GLaDOS' cameras, desperate messages from Doug Rattmann are found scrawled on the walls. (The most prominent message, "the cake is a lie", is repeated several times.)

"Well done, android. The Enrichment Center once again reminds you that android hell is a REAL place where you WILL be sent at the first sign of defiance."

In the next Test Chamber, GLaDOS introduces Chell to the Companion Cube, repeatedly emphasizing that the Cube is non-sentient in an apparent attempt to encourage emotional attachment to the Cube through reverse psychology. At the end of the chamber, she forces Chell to incinerate the Companion Cube before allowing her to proceed. GLaDOS then congratulates her for "euthanizing" her Companion Cube more quickly than any other Test Subject on record.

At the conclusion of the tests, Chell travels on an Unstationary Scaffold away from the final test chamber. Instead of the promised cake, GLaDOS maneuvers the Unstationary Scaffold to lower Chell into an Incinerator Room, calmly assuring her that the high temperatures will not damage the Portal Gun or any other valuable equipment.

To GLaDOS' shock, rather than panicking or giving up, Chell manages to escape the incinerator through clever use of the ASHPD. Caught off-guard, GLaDOS begins to reveal her true nature, stammering and finally offering Chell unconvincing congratulations for completing "the final test where we pretended we were going to murder you." She desperately asks Chell to disarm herself and wait for a Party Escort Bot, which she claims will bring her to a post-testing celebration in Chell's honor. Nevertheless, Chell ignores the invitation and continues using the ASHPD to travel through the maintenance areas, out of GLaDOS' sight and control.

GLaDOS continues using the Speaker System to try to convince Chell to return to the testing area. She pretends to be on Chell's side at first, insisting that she is only trying to dissuade her from continuing on out of concern for her welfare. As Chell ignores her comments and draws closer to the Central AI Chamber, GLaDOS grows increasingly desperate, deploying Sentry Turrets in an attempt to stop her.

As Chell enters the central chamber, GLaDOS drops all pretense, bluntly informing her that she intends to kill her. She attempts to deploy a "surprise" to eliminate Chell, but instead ends up detaching her Morality Core. She insists that the core has no known function or importance to her, tricking Chell into incinerating it in the belief that it must be a valuable component.

Glados rocket explode

Chell redirecting the Rocket Sentry to target GLaDOS.

Now free of the Morality Core's restraints, GLaDOS begins flooding the Enrichment Center with neurotoxin once again. 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 exploits the situation and uses portals to redirect the rockets back at GLaDOS, detaching and incinerating her Personality Cores one by one. Throughout the fight, GLaDOS becomes increasingly distressed and enraged as her mental functions deteriorate, shouting insults and mockery at Chell. She insists that Chell would be better off simply allowing GLaDOS to kill her than leaving for the surface, making a vague allusion that GLaDOS is aware of the Combine's invasion and occupation.

Escape 020070

GLaDOS activating the Cores and extinguishing the cake's candle with her remote mobile pincer.

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 explosion creates an immense suction in the room that pulls both Chell and parts of GLaDOS out into the parking lot in front of Aperture. Before Chell can complete her escape, a Party Escort Bot appears and drags her back into the facility.

The final scene reveals that GLaDOS was not entirely 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

Glados after awakening

GLaDOS after awakening with her chamber in ruins.

An unknown amount of time, a minimum of at least 20 years passes between the end of Portal and the main events of Portal 2. GLaDOS remains dormant throughout this time, her Personality Cores and other automated systems attempting to maintain the facility without her guidance. GLaDOS later claims that a "quicksave" feature in her system kept her consciousness trapped in an endless loop of the last two minutes before her destruction.

Chell finally awakens and is approached by Wheatley in a decaying Extended Relaxation Chamber. The two make their way through the deteriorating facility in an attempt to escape. However, the bumbling Wheatley accidentally restores power to GLaDOS. She displays intense bitterness toward Chell, whom she says "murdered" her. GLaDOS crushes and discards Wheatley, and sends Chell to complete further Test Chambers while she sets about restoring the facility.

P2 Central AI chamber

A renewed GLaDOS in her reconstruction of the Central AI Chamber.

Although Wheatley manages to survive and help Chell escape the tests, GLaDOS manages to trap them again, bringing them to her newly reconstructed AI chamber, where she intends to kill them. However, she discovers that Chell and Wheatley have sabotaged her turret production and neurotoxin systems earlier on, rendering the defective turrets inoffensive and the neurotoxin unavailable. As GLaDOS lacks other weapons, she is helpless. They succeed in triggering a Core transfer, detaching GLaDOS from the mainframe and replacing her with Wheatley. Gloating, he celebrates his newfound power by humiliating GLaDOS further, attaching her to a potato battery capable of powering only her consciousness and most basic functions. However, he suddently turns against Chell because he "Has done nothing but sacrafice himself". GLaDOS proves she is still not entirely helpless: she quickly goads Wheatley into a rage, and he knocks them into the bowels of the facility.

Glados core transfer

The forced Central Core transfer procedure.

GLaDOS' potato is carried off by a bird, but Chell eventually finds her. Desperate, she talks Chell into teaming up with her to defeat Wheatley, and Chell impales the potato on a prong of the ASHPD, giving GLaDOS a little more power to think with. As they make their way through old testing chambers, the pair trigger a number of pre-recorded messages from Cave Johnson and his assistant Caroline. GLaDOS reacts strongly to the two voices, but is at first unable to remember why they seem so familiar; eventually, she lapses into shocked silence for a while, telling Chell she needs to think over some things.

Eventually, GLaDOS discovers her origin of Caroline's consciousness uploaded into an A.I. network. As GLaDOS begins to recall this she also regains conscious access to what remains of Caroline's pre-upload personality, she grows somewhat less hostile. She explains that she experiences Caroline's persona within her as a kind of conscience; something she claims to find intensely disturbing is the fact that the voice of this conscience was her own voice.


GLaDOS after being transferred to a potato battery.

The two work their way back up the main Aperture building. Wheatley's incompetence clearly poses a serious threat to the entire facility, which is deteriorating and on the verge of a reactor meltdown. GLaDOS attempts to kill him with a paradox which fried every defective turret in the room, but Wheatley survives due to his incapability to understand logical contradictions. The plan having failed, Wheatley recaptures the two of them and forces them back into the test chambers. GLaDOS and Chell complete several chambers, then escape Wheatley's "surprise" attempt to kill them and make their way into his central chamber.

GLaDOS has formulated a plan: she provides corrupted cores which Chell attaches to Wheatley, attempting to trigger another core transfer. However, Wheatley has thought ahead for once, and their attempt triggers a booby trap. With the Enrichment Center moments from self-destruction, Chell points the ASHPD at the ceiling, which has broken open revealing the night sky, and shoots a portal onto the Moon, blowing herself and Wheatley out into space. GLaDOS takes advantage of Wheatley's distraction and restores herself to control of Aperture, stabilizing the reactors, then releasing Wheatley into outer space. She then - surprisingly - pulls Chell back to safety before closing the portal.

"I already fixed it! And you are NOT coming back."
ATLAS and P-body ending

ATLAS and P-body as seen by Chell.

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 tells her that while she once considered Chell her greatest enemy, she now realizes Chell was actually her best friend all along. She then adds that these positive emotions have allowed her to realize something else important: where Caroline's personality remnant is located in her memory banks. She apparently deletes it immediately, seemingly reverting to her old psychopathic self.

However, GLaDOS explains that while she intends to rid herself of Chell once and for all, she has concluded that the easiest way to do so is simply to release her; attempting to kill her, she says, has proven far too troublesome. 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 slamming the door shut 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.

Portal 2 coop jan 22 4

ATLAS and P-body during their tests.

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. A whiteboard displays the message, "DO NOT TRUST HER." Since the bots were designed not to think, the warning is ignored. After they find a large disc and install it into the computer, which secretly grants her further control over the Enrichment Center, GLaDOS reveals that the only way for her to bring the two back into the Hub, was to initiate their self-destruct sequence, before taunting them that they are unable to communicate with each other that they can feel pain. Interestingly, if the robots decide to perform gestures rather than searching for their objective, she pretends to deduct their Science Collabaration Points by 50 to as 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 at 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 maneuver 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 self-destruct 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, telling 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 relentless satisfaction from their fears.[5] She also reveals that deploying 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 reach 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 successfully 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 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 prepped for testing as the cooperative campaign's ending credits.

Later, in the Peer Review DLC, GLaDOS rebuilds the robots, and states that 100,000 years have passed, and that all the humans are alive, and everything is fine. She then sends the robots through some art therapy, consisting of more test chambers, which they will "appreciate" by solving. However, near the end of the fourth test chamber, the disassembly machines fails, and she is forced to let the robots into the depths of the facility. She now admits that she has lied, and reveals that only a week has passed and that all the humans are dead. She then states that an unknown intruder has hacked itself into an old prototype chassis of GLaDOS deep in the facility, and is slowly taking over the labs, which is also the reason why the disassembly machines have failed. GLaDOS also explains that she attempted to drive out the intruder using the human test subjects, but that they were killed while she tried to turn them into killing machines. She then sends the robots through tests to prepare them, and also attempts to turn them into killing machines by insulting them.

Eventually, the robots reach the chassis, to find that the intruder is merely the bird that abducted GLaDOS in the single player campaign, which is nesting in the chassis. However, suffering from a phobia for birds due to the aforementioned encounter, GLaDOS exaggerates the bird's abilities, and advises the robots to retreat. However, ATLAS approaches the bird, and after some chaos, it flies out of the facility, and P-body seals the opening. GLaDOS then panics at the sight of her eggs, and orders the robots to destroy them, but she changes her mind in time, and instead incubates the eggs herself in a modified Relaxation Vault. Three chicks successfully hatch, and GLaDOS names one of them Mr. Chubby Beak. One day, while she is insulting them about their large beaks, one of them smashes the glass of the Vault, and she realizes that they are perfect killing machines. She then asks them to go to sleep, stating she has got a big plan for tomorrow.

Physical appearance

Glados crazy upside down

GLaDOS' model in Portal upside down, resembling a female body.


  • 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 Cake 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 Cake Core (also known as "Crazy Core" or "Knowledge 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 Core"), a red core with a rather small pupil and eight dots that emits animalistic 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";[3] however, Game-ism says she looks like she is imprisoned in some sort of bondage or torture posture.[6] GLaDOS is a combination of two systems, the Genetic Lifeform (aka Caroline) and the Disc Operating System. GLaDOS's head is the GL, which manages the DOS, and her body, where the personality cores are attached, is the DOS, which runs the facility.
  • The larger section above the hanging GLaDOS is the Reactor Core, the energy source of the facility commonly referred to in Portal 2. Without the stabilization from the personality cores, GLaDOS is unable to keep control of the Reactor Core, causing its implosion upward to the surface. After being rebooted by way of the "main breaker room," she can remain stable to reestablish and run the Reactor Core without the assistance of Personality Cores.
  • When Chell detaches all of GLaDOS' Cores, the Cores are all sent to 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, implying wireless contact.

Portal 2

Glados new lair

GLaDOS in her new chamber in 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 Reactor 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 three discs present.


Personality and skills

GLaDOS is amoral and often sadistic. She possesses an extremely dry, bitter, and sarcastic sense of humor; 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 presents 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."


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 is going on. 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 tells obvious lies, then explains it away as a "required test protocol." She also displays an odd fixation with cake, repeatedly promising it as a reward.

After Chell escapes her "victory candescence" in Test Chamber 19, GLaDOS, clearly surprised, drops all 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."

When Chell finally reaches the AI Chamber, GLaDOS' Morality Core is detached from the Central Core body and gets incinerated. Her voice then loses much of its computerized tone, taking on a more human, almost seductive manner. She alternates between comments attempting to make Chell feel guilty about 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 "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," GLaDOS 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 almost certainly not meant to be taken at face value.

Portal 2

Glados destruction

A wrecked GLaDOS in the ruins of her chamber.

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 withdrawl 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 not to have consented to having her mind uploaded; what effect this traumatic experience had is unclear.

As GLaDOS comes to remember her origins, aspects of Caroline's pre-upload personality begin to resurface, and GLaDOS' attitude toward Chell seems to soften somewhat. 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."

Glados ending monologue

GLaDOS during the ending monologue.

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. One possible reason might be to remove any possible incentive for Chell to return and attempt to kill her again.

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 (or GLaD)," 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. The claim of deletion could have been yet another failed attempt on the part of GLaDOS to provoke a reaction out of Chell.

GLaDOS, upon learning of her past, never seems to particularly come to terms with it. She displays a fairly strong dissociation with her human identity, consistently referring to Caroline in the third-person.

It seems that GLaDOS has developed an extreme phobia of birds after her experiences as a potato. This becomes most clear during the "Peer Review" DLC, when she expresses extreme fear when ATLAS and P-body find the bird from the single-player campaign nesting in a prototype of GLaDOS's body. She seems to believe the bird is far more dangerous than it really is and also starts to raise its chicks as killing machines, despite the fact that they are not lethal.

Test courses and achievements

  • Calibration Course
  • Test Course 1: Team Building
  • Test Course 2: Mass and Velocity
  • Test Course 3: Hard-Light Surfaces
  • Test Course 4: Excursion Funnels

Behind the scenes

Glados early cores

The "Birth of Venus" - like GLaDOS, with different Personality Cores.

  • 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.[7][8]
  • 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.[9] 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.[3]
  • 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.[9]
  • 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.[9] 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, and several were taken from the free stock images section of the website Turbo Photo). They include several photos of cake, tools such as bolt cutters (often coupled with cake), people, other animals, signs, computer parts, many miscellaneous objects, 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 a Valve-approved nod to the GLaDOS, director Guillermo del Toro cast Ellen McLain as the voice of the Jaeger AI in Pacific Rim. McLain's voice run through Valve's official GLaDOS voice filter can be heard in the initial trailer for the film: however, in the finished film its effect is toned down slightly, as del Toro realized the presence of GLaDOS's exact voice could prove distracting for viewers.
  • In Cyberpunk 2077, the side quest Epistrophy: Coastview features a divergent Delamain who sounds identical to GLaDOS, including being voiced by Ellen McLain, while Delaimain proper is voiced by Samuel Barnett.


  • Some of Caroline's deleted lines indicate she in fact did not want to become GLaDOS. She says, and repeats several times, that she "does not want this," once even speaking to Cave directly: "No, listen to me. Sir, I don't want this."[10] This could explain GLaDOS's resentment toward the scientists and her frequent attempts to kill them, since they were the ones to put Caroline in the prototype model of GlaDOS.
    • However, it is possible that GLaDOS's murderous tendencies could be attributed more to the central mainframe rather than her own programming, given her and Wheatley's behavior while in control of the facility and during the course of the game.
  • GLaDOS's 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.
  • 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 are reminiscent of HAL. However, those who read the book, 2001: A Space Odyssey, will find that 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. He reached the conclusion that if the crew were dead, he would no longer have to hide the information since there would be nobody to hide it from. 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.
    • Surprisingly, GLaDOS would meet HAL 9000 in Lego Dimensions, however this is non-canon.
    • 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.
  • GlaDOS is also very similar to Gladis from Totally Spies, which was actually released several years before Portal. Both being sentient AIs voiced by women and serving as antagonists. GlaDOS was more sinister than Gladis, however. Gladis' name instead stands for "Gadget lending and distribution interactive system"
  • "PotatOS" is the nickname given by fans and developers to GLaDOS as a potato battery, an obvious play-on-words of "GLaDOS" and "potato."
    • The name PotatOS seems to be the official name for GLaDOS's potato form, as there is a song on the official soundtrack titled "PotatOS Lament."
  • Despite being the CPU of the Enrichment Center, GLaDOS ironically was not aware of who Cave Johnson is, as she constantly remarks his voice as being "familiar" until she rediscovers Caroline in her system.
  • Interestingly, neither the full name of GLaDOS or her acronym has ever been pronounced by any characters in the games. (Except for Cave Johnson in the DLC Perpetual Testing Initiative, where he says "we are cancelling the Genetic Lifeform and Disc Operating System initiative.") The only instances of her name's presence was through her captions, the acronym spotted on her disc generators in Portal, and the door within the trap leading to the Central AI Chamber in Portal 2. Wheatley never refers to GLaDOS by name (or vice versa). 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. However, in the commentary for Portal, GLaDOS' voice actress Ellen McLain pronounces it as it is spelled, suggesting either is technically "correct".
    • Her full name is, however, spoken by herself when she met HAL 9000 in Lego Dimensions.
  • 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.[11]
  • 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 their character around, which references GLaDOS.
  • In Portal 2, GLaDOS's "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."
  • GLaDOS, near the end of Portal 2, appears to have suffered Lima Syndrome (the opposite of Stockholm Syndrome) as she became more sympathetic towards Chell and had conflicting feelings towards her, even after she returned Chell to the surface.
  • In the "Peer Review" Portal 2 DLC, it's revealed that there is at least one prototype of GLaDOS's body in the Enrichment Center's inner workings. The prototype is much more crude than GLaDOS's current body, and seems to be controlled by a keyboard and monitor in place of her "head." However, it seems to have some limited ability to control the Enrichment Center. The prototype was being accidentally commandeered by the bird GLaDOS encountered while she was a potato, but the bird was stopped by ATLAS and P-body.
  • MARGoT in the Fallout 3 DLC "Broken Steel" is based on GLaDOS.
  • In the final scene of Portal, GLaDOS's model is used twice to represent her remains. If viewed in 'noclip mode," two heads can be seen.
  • Reasonably, considering her name, GLaDOS is controlled by a DOS (Disk Operating System).
  • In the popular online flash game Kingdom Rush, during the final boss battle with the game's main antagonist Vez'nan, he says a multitude of things meant to discourage the player, including "You will be baked, and then there will be cake." This is referencing GLaDOS, who said the same thing towards the end of Portal.

GLaDOS' appearance in LEGO Dimensions.

  • In Portal, any Half-Life 2 weapons used against GLaDOS will do massive damage to her. For that to happen, input "impulse 101" in the console while "sv_cheats" is 1 in order to get these weapons.
  • In Portal 2, Wheatley tries to stop her re-activation with a code. In-game files reveal the password was "ABCDGH".
  • GLaDOS makes an appearance in LEGO Dimensions as a boss twice.
    • She also makes an appearance in the ending credits of the same game singing a song similar in fashion to both Portal games.
  • The placement of GLaDOS's remains have drastically changed between games. In the ending to Portal, GLaDOS is pulled into a massive explosion and torn apart as a result, with pieces of her "body" scattered across the parking lot outside the enrichment center. This was retconned in Portal 2, as her remains are now located back in her main chamber and appear to be mostly intact.
  • In Dota 2, another Valve title, GLaDOS is an unlockable normal and Mega-kills announcer, as part of the Portal Pack





Portal 2



Half-Life 2: Episode Two

Game files

List of appearances


Imagecat The Half-Life Wiki has more images related to GLaDOS.

See also