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Disambiguous This article is about the character also known as "Subject Zero". For the passive class power used by this character, see Subject Zero (power).

“Turns out, mess with someone's head enough and you can turn a scared kid into an all-powerful bitch.”

Jack, also known as Subject Zero, is a notorious criminal whose crimes include piracy, kidnapping, vandalism and murder. She is also a biotic, possibly one of the most powerful human biotics alive, and is considered so dangerous that she was kept in cryogenic stasis after she was caught. She is a potential romance interest for a male Shepard.

Mass Effect: Foundation[]

Jack assaulted a Cerberus facility and headed straight for Doctor Angersol, an administrator who was one of the people involved during her formative years as Subject Zero. She demanded her life back from the doctor, then executed him since it was impossible. The Illusive Man appeared before her via hologram, but Jack raged against him and what his facility represented before he can get anywhere. She just dared the Cerberus leader to take his best shot at stopping her.

Jack intrigued

The Cerberus facility went on lockdown, and Jack set about looking for its main reactor. She came across an unarmed man and threatened him for directions, but became astonished to hear that the man was a student trainee at the facility, not a worker. Curious, she ordered the man to take her to his peers.

Jack learned that the students perceive they have better lives under Cerberus care, with most of them having lost their parents from an early age. She revealed an ugly truth to her trainee companion: that's just what Cerberus told their subjects, and she found out her parents were murdered just so they can get her.

The other students milled about their dormitory due to the alarms going off across the base, so when Jack and her companion reached them she gave them all a choice: discard what they knew about Cerberus and escape with her, or stay and continue to hope that Cerberus won't just discard them once they're useless. She drew upon personal experience to convince them further, that Cerberus won't ever let them go without a fight.

Sticks and guns against the psychotic biotic

A number of students, albeit panicked, heeded her words and followed her around the facility. Jack brushed off suggestions to head to the hangar, as she anticipated their pursuers there. She heard voices around a corner they're supposed to go in, so she ordered the students to sneak past once she diverted the hostiles' attention.

A trio of bored Blue Suns mercs got biotically pelted by heavy objects Jack sent their way. She brought down the ceiling above the mercs as she ordered the students to run. A couple of Cerberus agents showed up shortly afterward intending to do her harm, and Jack mused to herself she thought she killed all of them.

Jack paid no concern to their threats; she simply unleashed a wave of biotic energy to knock them backwards. She warned the woman, Rasa, to stay down, but the other one, Kai Leng, was already behind trying to hit her from above. Jack sensed the attack and sent Leng flying again, deeming the move not good enough.

More Blue Suns arrived at the commotion, forcing Jack to throw up a biotic barrier when they opened fire. Her rage boiled at what she deemed dirty tactics when she saw her students behind Blue Suns lines. Jack marshaled her powers and sent everything in the vicinity flying, intending to kill everyone. The plan was stopped short, however, when a krogan merc hit her head from behind, causing her to lose consciousness. She was then hauled off to Blue Suns custody, to the consternation of the Cerberus agents sent to catch her.

Mass Effect 2[]

For her gameplay attributes in Mass Effect 2, see Squad Members Guide (Mass Effect 2)#Jack.
Jack in action

Jack was born in 2161 and abducted by Cerberus operatives in 2165 from Eden Prime, although it is unknown whether that was her birthplace. Cerberus' motives pertained to her newly discovered biotic potential, a result of accidental exposure to element zero in the womb. As a cover for her abduction, her mother was told that she had died due to complications of her eezo exposure. After initial tests, Jack became the prime subject of a sizable Cerberus experiment on Pragia's Teltin facility, with the goal of enhancing biotic potential in humans, regardless of the cost. The project was a typical Cerberus operation: lavishly funded, highly efficient, and morally indifferent, with a heavy reliance on brutal human experimentation and conditioning techniques in an attempt to maximize results.

Referred to as Subject Zero, Jack was the core of the project, with every successful biotic enhancement applied to her. Many other children of lesser biotic ability were also kept as part of the experiment and treated as expendable lab animals, with many dying in trial runs of treatments to ensure that they would be successful on Zero. Any enhancements that proved lethal were not applied to Jack. She was tortured frequently, both psychologically and physically, in various experiments to test how pain and distress affected her biotic abilities. As she grew in both age and hatred for her captors, her powers eventually advanced to such a level that she became a serious threat to the staff, easily killing one by blasting him into a wall. Kept separate from other children, she grew up believing that the entire world was what she could see outside her window and repeatedly screamed herself hoarse while trying to communicate with others through her soundproofed cell. In reality, the window was a one-way mirror, intended as just another form of psychological torture.

Jack under Engineering on the Normandy

As they were regularly and remorselessly killed in various experiments designed solely to advance Jack's biotic abilities, the other kids grew to despise her as the source of all their suffering. This was only made worse by the fact that (on account of the one-way mirror) the only time they ever saw her was when the staff forced her to fight the other students gladiator-style in order to monitor her biotic progress and condition her to love the act of killing; she would even be injected with narcotic drugs during the fights to further associate killing with euphoria in her mind.

Eventually, while being led to another deadly experiment, the children rioted and attacked the guards. Backed up by their biotics, the riot caused damage to the facility and Zero was freed. At this point her powers had grown so great that nothing could stop her. She would later have difficulty remembering those events for the next years in her life, due to her age at the time and the chaos. She would claim the guards and children attacked her, forcing her to kill them all. When she returned to Teltin, recorded logs rendered it more likely that the children were attempting either to get close to her for safety, since the guards had been ordered to keep Jack alive, or were trying to kill her as a measure of revenge. In either case, Jack's pent-up rage and sudden release from captivity caused her to fly into a fury, killing almost everyone in the facility in a furious biotic rampage before stealing a shuttle and flying off Pragia into the Dakka system, where it was picked up by another ship after several days. Rather than helping her, the crew "used" her before selling her off as a slave.

The Teltin facility on Pragia was shut down by the Illusive Man shortly after Jack's escape. Although operating as an official Cerberus cell and receiving Cerberus funding, years later the Illusive Man would state he was initially unaware of the brutality of Teltin's experiments, claiming that he shut the facility down after finding out it had "gone rogue". This official stance is echoed by Miranda Lawson, who (when confronted by Jack) refuses to admit blame on behalf of Cerberus for Jack's experience, calling her ordeal a "mistake" and blaming it on a splinter group.

Subject Zero

After her escape, Subject Zero went on to live a predictably violent and bloody life. In order to sever ties with her past she took on the name Jack, and reacts violently whenever addressed by her former designation. She ran with various gangs, became a pirate, crashed a space station into a hanar moon (becoming wanted for vandalism in the process), and at one point joined a cult, keeping her head shaved even after her departure.

Eventually she was captured and imprisoned in the Blue Suns operated prison ship, Purgatory. During her time there, she was attacked by a group of guards and prisoners who raped her, despite her efforts at fighting back. Their victory was short-lived however, as Jack personally murdered every one of her attackers as soon as she healed. The incident led the Warden, eager for the amount of credits Jack could bring him from Cerberus and other buyers, to lock Jack in cryostasis, for both her and others' safety until Shepard's team came to buy her freedom.

The tortures of Jack's time as Subject Zero and her subsequent life experiences have rendered her a borderline psychopath, with an unpredictably violent nature and a severely antisocial personality. She has an innate lust for violence, claiming to experience "warm feelings during a fight" due to her physiological conditioning as a child at Teltin (by shocking her for hesitating and stimulating her with drugs whenever she attacked). She has a tendency to spout profanities constantly in conversation and is very easily provoked. Her body is covered head-to-toe in elaborate tattoos and scars, some being remnants of her experimentation, while others mark prisons, kills, and major events in her life. Having been used and abused so many times by people in her life, Jack refuses to trust anyone and is clearly both angered and confused by Shepard's attempts at conversation, being unable to determine what the Commander wants from her.

Yet underneath all of this, she is still frightened and tormented by memories of her past and longs for some kind of closure. She joins Shepard's team in exchange for Cerberus files detailing her experimentation at Teltin, after which she asks the Commander to help her destroy the now abandoned facility with a "huge bomb", symbolically planting it directly in the cell that was the source of all her misery.


“I want to go to the center of the place, my cell. I want to deploy a big fucking bomb. And I want to watch from orbit when it goes.”
Main article: Jack: Subject Zero

After looking through her files, Jack wants to deploy a bomb at the Teltin facility on Pragia, where Cerberus conducted their experiments on her.

Shepard takes Jack to the facility, unexpectedly encountering Blood Pack mercenaries. After fighting through the mercs, they find another test subject, Aresh. Aresh hired the mercs to restore the Teltin facility in exchange for salvage. Jack wants to kill him, but Shepard has the option to stop her. The two plant the bomb in Jack's cell, and use the shuttle to escape before detonation.

If Miranda's loyalty mission has already been completed, once Shepard returns to the Normandy, Shepard will have to resolve a dispute between Jack and Miranda regarding the involvement of Cerberus in Jack's torture. Shepard can resolve the conflict without picking a side, in which case, both Jack and Miranda agree to put off their fight until after the mission with the Collectors is over. If Shepard sides with Miranda, then the Commander will lose Jack's loyalty, but has the opportunity to regain her loyalty in a later conversation. In addition, if Shepard was in a romance with Jack, and sided with Miranda, then Jack will break off the relationship and will refuse to rekindle it.


“You know what it's like... to think you're alone and find out you're not?”

During a conversation Shepard has the option to have casual sex with Jack. If Shepard agrees, a feisty sex scene in the small quarters on the engineering deck occurs. However, after the sex scene, Jack refuses to speak to Shepard anymore, telling him that there is nothing to talk about any time a conversation is attempted. It is possible to have casual sex with Jack even after Shepard successfully pursues other romantic options such as Tali or Miranda.

Jack in Shepard's cabin.

Should Shepard choose to turn down the casual sex option, get to know her first, and pursue a relationship, the result is very different. Jack will eventually soften up and reveal a lot about her past, where on multiple occasions she was taken advantage of when she let her guard down. She also references a time where Murtock, one of her partners, worked with her on a weapons frigate. When they got split, he chose to stay behind rather than abandon her to die, getting himself killed in the process. He left a recording on their shuttle for her in case he died, and when it rolled after one day, it talked about the future they were supposed to have, how he planned to build a home for them, about how he loved her and was sorry it wasn't going to happen. This implies a great deal of "survivor guilt" in Jack from the incident and her time spent on Pragia. She eventually tells Shepard that she needs time to think about everything; it's all very new to her and she isn't quite sure what to do.

En route to the final mission, she comes to Shepard in his cabin, tells him she has been thinking a lot about him, and that he's right and she needs someone. Jack gives in, and shows a very vulnerable and emotional side. Tears roll down her face as a tender scene ensues, culminating with her smiling peacefully while they lie together on his bed, and she finally achieves true happiness.

At some point prior to the love scene, Mordin Solus will offer advice to Shepard in regards to his attraction to Jack, mostly concerning the fact that she is likely to either accidentally or purposefully kill him if he keeps trying to get close to her. He will offer to send information packets on biotics and mass effect field manipulation to Shepard's quarters.

If at the point just prior to the love scene when Jack tells Shepard about the partner who sacrificed himself for her -- or even right during the actual love scene -- should Shepard choose to reject her as a lost cause who will never be "normal", Jack will angrily accuse Shepard of being just one more person to simply use her and storm out of his presence. After this choice, every time Shepard goes down to talk to her in Engineering she will simply yell an obscenity at him.

Lair of the Shadow Broker[]

After the showdown with the Shadow Broker at his base, if Shepard brings Liara aboard the Normandy to catch up, she will ask Shepard what he's fighting for, and if it's a chance to give Jack faith in something more than anger. If Shepard answers yes, he says that she is getting better, relatively speaking. Liara does not find Shepard's explanation reassuring, to which Shepard somewhat agrees, but she is still important to him nevertheless. Before she leaves to return to the Shadow Broker Base, Liara will say that she hopes that the two of them will find happiness together.

Mass Effect 3[]

“I'm dependable now. I blame you for this, Shepard.”
Jack in 2186

In 2186, provided she survived the Suicide Mission, Jack has altered her appearance, having grown out her hair into a pony tail, but retaining the shaven sides. She now sports a punky studded jacket over a white top that reveals her midriff and its numerous tattoos. She has become more mature, and states that some of Shepard's attitude rubbed off on her.

Sometime after the Collectors' defeat, Jack was approached by the Systems Alliance and offered a teaching position at the Grissom Academy to train biotics for combat. She accepted and agreed to tone down her profanity to maintain the level of professionalism expected from teachers. Her students apparently responded well to her unconventional teaching style, mimicking her trash talk ("I will destroy you!") and sticking affectionate appellations like "the psychotic biotic". Jack herself grew attached to her charges in return, considering them the family she never had, and promises to exact retribution against anyone who screws with her kids.

Jack is present on the station during Cerberus' attempt to kidnap gifted students for their cause, defending hers from being captured. Shepard finds Jack in the middle of shielding one of her students from incoming Atlas fire, and while Shepard's team takes care of the opposition Jack rallies to her kids on higher ground, helping project a biotic barrier and supporting biotic strikes.

Jack with her students at Grissom Academy

Jack's fist lands on Shepard's face the moment the smoke clears, the exact reason why depends on Shepard's previous actions. If a male Shepard romanced her, she hit him for leaving her, then immediately kisses him passionately afterwards. If Shepard expresses misgivings about previously working with Cerberus, Jack cites either handing over the Collector Base to them or the deaths they've caused as her reason. If Shepard merely reminds her how they saved her ass, Jack sarcastically asks if they want a medal. Whichever the case, Shepard's squadmates interject and Jack has some choice replies for some of them.

After giving instructions to her students and admonishments to Jason Prangley, Jack relates to Shepard the things she's been up to over the past few months. If the conversation turns into improving the students' endurance and conditioning, Jack specifically recalls her time in the Suicide Mission either throwing husks around or being Shepard's biotic bubble specialist whenever the students complain, telling the kids she kept thinking that she should've let Mordin handle her job instead as he can "talk [the Collectors] to death." If Mordin died, though, Jack feels bad, recalling the "wicked sex advice" he often gave. Once all the catch-up is over she stays put until Shepard paves the way for their exit route.

One of her students, Ensign Rodriguez, wavers when Cerberus starts messaging the students, and Jack gives the student a dressing-down. Jack either gives Rodriguez her coarse affirmation of her student's abilities, or shoves the surgery scars inflicted during her Cerberus captivity into her scared student's view, angrily asserting that surrender is tantamount to being meat on a slab. The Ensign sets her head straight after this, and Jack leads the students in shadowing Shepard's team from higher ground while the squad clears out the bulk of Cerberus resistance. Privately, Jack believes her kids aren't yet ready for the realities of war, but Shepard can influence her into letting the students run loose for a while even if they're only fighting from relatively safe positions.

Jack, Shepard and Kahlee Sanders eventually manage to help the students escape. Jack, in a good mood, wants to treat her kids to tattoos at the next place they dock. If a male Shepard chose to break with her earlier, Jack even mentions hanging on to the N7 tattoo on her ass she previously planned to burn off. As they make their way back to the Normandy, Jack decides to break her self-censoring when Joker takes note of the fact and wisecracks that if Jack had a swear jar the cash inside would've been sufficient to buy a cruiser.

Jack spends her shore leave in Purgatory.

After the rescue from Jon Grissom Academy, Jack can be found on the Citadel in Purgatory Bar after the attempted Cerberus coup reading duty rosters for her kids even while on shore leave. Shepard can either tell her to keep at it, or convince her to lighten up a bit, which colors Jack's responses throughout the conversation.

If Shepard thinks Jack fits in snugly to military life, Jack says that their little suicide squad apparently taught her something about teamwork. If the students had been sent to the front lines, Jack mentions her kids are being sent into hot spots for hit-and-runs and she's making sure the higher-ups won't give them something way out of their league. She expresses her surprise at their ability to hold up under fire, but then Shepard believed in the students' abilities and burned away her doubts. If the students had been assigned support roles, she remarks they've been spread out across Alliance units, saving a lot of lives by providing barrier support, modding ammo and the like, and that they're handling the support duties well.

If Shepard convinced Jack to take her job seriously, Jack mentions that her kids even saw action on Palaven, either on the front lines with Prangley displaying exceptional biotic aptitude against Cannibals and Rodriguez not panicking for a change, or that her kids provided barriers for a krogan squad so the latter can get close and break enemy lines. They manage to help the turians evac a thousand civilians to safety.

She never got laid

Jack suggests fighting would be more fun with Shepard as the Commander finds bigger fights, but claims the "little shits" would be useless without her, and blames Shepard for the perception that she's apparently "dependable" now.

If Jack was previously romanced, Shepard has the option to rekindle or officially end their relationship at this time. The Commander asks Jack to dance with them, regardless of whether she was romanced or not, claiming that she's on shore leave and the rosters can wait. Jack flat-out retorts that everyone knows Shepard can't dance, and with that they both enjoy the music.

If Shepard does not help Grissom Academy in time, she will appear as a special enemy Phantom when Shepard raids Cerberus Headquarters. An audio log can be found where Jack is heard resisting her captors up until the end. After the squad is forced to kill her, Shepard states that she was no longer herself and that she is "just one more thing Cerberus will answer for."

Green-eyed Jack pondering if her students' sacrifice was worth it

In the final battle on Earth, Shepard can speak with the communications officer in order to call Jack. Jack indicates that she's in the fight but can't reach Shepard's location. If a male Shepard has a romance with Jack, Jack will tell Shepard that he needs to survive, because she is "getting laid" after the war is over. If Shepard chooses to use the Crucible, Jack can be seen gazing at the stars in the future.

If Jack didn't have a relationship with Shepard by the time the Commander uses the Crucible, her fate will be determined by the path her students took. She will either be seen visiting her students' graves if they were previously sent to the front lines, or she will be seen with her kids — alive — and Kahlee Sanders mulling their next move if the students were relegated to support.

If Jack did not survive Shepard's suicide mission, her name will be engraved in the memorial wall on the Normandy as Jacqueline Nought, a pseudonym she used at least once in the past.

Mass Effect 3: Citadel[]

For her gameplay attributes in Mass Effect 3, see Squad Members Guide (Mass Effect 3)#Jack.
Ooh, and that was Cerberus attacking the academy

Jack's ally license can be bought at the Armax Arsenal Arena, provided that Shepard rescued her from the Cerberus attack on Grissom Academy.

After the conclusion of Shepard's clone fiasco, Jack messages the Commander, requesting a meet-up at the Armax Arsenal Arena. When Shepard arrives, they have a two-round match against Elite Cerberus Troops in Brimstone. Once the Atlas Mech spawns, Jack takes it down herself and thanks Shepard for the get-together. If Jack is romanced, she will kiss Shepard when the Atlas explodes.

Afterwards, Jack sends another message informing Shepard of having more free time. Shepard can then invite Jack to the apartment. Jack brings along Eezo, a varren from Thessia that she had rescued from shelter. Because of his exposure to the element zero in the environment on Thessia, Eezo has developed biotic abilities. According to Jack, biotic abilities in varren make them short-tempered, leading to their abuse and abandonment. When Jack first rescued him, Eezo started out very angry and mistrustful of others, but all the love she has shown him has made him a "big old softy" to the point where he plays catch with Shepard. Shepard has the option of pointing out the similarities between Eezo and Jack. If Shepard does, Jack will say she doesn't know what Shepard is talking about and Shepard will quickly drop the subject.

If Shepard is still in a relationship with Jack at that time, she will instead bring equipment to mark Shepard with a tattoo on his back. As Shepard comments on the design, she confesses she did this to make his body identifiable no matter what happens to him in the final battle.

If invited to the party, Jack is first seen by the fireplace hanging out with Vega and Cortez. If Kaidan is also invited, the conversation within the group arrives at the point where Jack gives James the nickname "Muscles", which Cortez will approve.

If Miranda is around, Jack is later seen lounging near the poker table having a somewhat prickly conversation with Miranda. Shepard can suggest they should just kiss each other because Shepard believes that there's some sexual tension between them, saying that they're "two powerful biotics". They find the notion disgusting. Kasumi, if present, then decloaks, saying that she could film it. Alternately, Shepard can encourage their rivalry, with Jack making repeated references to whooping Miranda's ass. Kasumi, again if around, decloaks, claiming she doesn't follow their conversation and just assumes they are going somewhere dirty with it.

If Miranda is not around, Jack is hanging out with Liara and James on the balcony at the second phase of an energetic party, watching the two argue about physical vs biotic supremacy. If the second phase of the party is quieter, then regardless of Miranda's presence or absence Jack will be at the bar with EDI and Cortez, where Jack may note that crème de menthe hits her even harder than ryncol.

Rowdy parties are right up Jack's (back) alley

At the third phase of the party, Jack is seen dancing provocatively on a table in the kitchen area if the party is energetic. If Garrus isn't around to comment, Jack's response to Tali's drunken musings while dancing is that she finds the quarian adorable, and says so in her own words: "If I were a little drunker and knew how to unzip that suit..." If Tali wonders instead about how humans and asari can dance given the way "their" legs bend Jack replies that she doesn't tip over until she found company, telling the quarian to "watch and learn" till then.

If the party is relatively restrained at the final leg, Jack is just standing by the upper floor couches, hanging out with Joker, Cortez, and most of the other guests.

The morning after the party, she will be joining Jacob's morning workout with pull-ups, attributing her hangover immunity to her amp.


  • Concept art of Jack's tattoos
    Concept art on Jack's tattoos figure backstories for several of the designs. Jack's "murdered sisters" were apparently based on prototype designs for her own appearance.
  • The Shadow Broker dossier on Cerberus lists the birth year of "Subject Zero" as 2161. However, in the dossier on Jack herself, the surveillance log of the Helios Medical Facility dated 2165 contains references to her as a "baby" and an "infant", words that aren't normally used to describe a child at 3-4 years old.[1]
  • Courtenay Taylor, who voiced Jack, also voiced the Cathar Jedi Juhani in Star Wars: Knights of the Old Republic as well as Farinden and Shaevra in BioWare's Dragon Age: Origins.
  • Jack periodically yells "I will destroy you!" and "I'll kill you!" when in combat and/or using abilities. This may be a reference to the combat barks used by humanoid enemies in Mass Effect or by Juhani in Knights of the Old Republic.
  • Jack's name and shaved head might be a reference to the character Jack/Kyra from the Chronicles of Riddick movie series, more specifically the first movie Pitch Black, in which the character was approximately 14 years of age. The two characters also share similarities in that they are both killers and are found in prison, which they both escape from with the help of the protagonist.
  • According to the Shadow Broker's dossier on her, she has used the name Jacqueline Nought on at least one occasion. "Jacqueline" is a typically feminine counterpart to "Jack," and "nought" is an English word meaning "nothing, zero".
  • Jack was originally intended to be a pansexual romance until negative backlash from Fox News concerning the first Mass Effect game forced a reassessment late in Mass Effect 2's development. Despite being unromanceable by a female Shepard, bits of Jack's orientation are still present in the games as per her tale about sleeping with both a man and a woman, both criminals, in her backstory.[2][3] Scenes were animated for both male and female Shepards, but didn't make it into the final product.[4]
  • Jack Mugshot
    During the car chase scene in the Lair of the Shadow Broker DLC, a wanted poster of Jack can be seen displayed on a large advertising screen above a tunnel. She is displayed with the prisoner number 24601.
  • If brought along on the mission Grissom Academy: Emergency Evacuation, Liara reveals that Jack's real first name is Jennifer and offers to find out her last name if she asks politely.

See also[]