Jack

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 considered so dangerous she was kept in stasis after she was caught. She is a potential romance interest for a male Shepard.

Jack is voiced by Courtenay Taylor.

Weapon proficiencies

 * Heavy Pistols
 * Shotguns

Dossier
Born in 2161, Jack was 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.

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.

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.

Loyalty
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. 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.

Romance
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.

Should Shepard choose to turn down the casual sex option, get to know her first, and pursue a paragon 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 one partner 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, 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 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 and attempts to talk to her, she will simply yell an obscenity at him.

Lair of the Shadow Broker
After the completion of Lair of the Shadow Broker, 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 did 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
In 2186, Jack has somewhat toned down her appearance, having grown out her hair into a pony tail, but still keeping the shaven sides. She is considerably more appropriately clothed for her situations, being fully clothed, although still with the punk look as the jacket she wears is studded, and her numerous tattoos still show through. She has become slightly more mature, explaining that some of Shepard's attitude rubbed off on her.

Sometime after the defeat of the Collectors, Jack is approached by the Systems Alliance and offered a teaching position at the Grissom Academy to train biotics. She accepted, though was forced to tone down her profanity. She is present on the station during a Cerberus attack, defending her students from being captured. When Shepard arrives to help, Jack, Shepard and Kahlee Sanders manage to help the students escape. As they make their way back to the Normandy, Jack decides to swear at Joker when he cracks jokes about having a swear jar.

After the rescue from Jon Grissom Academy, Jack can be found on the Citadel in Purgatory Bar, provided authorization for her students has been granted, and not until after the Cerberus raid on the Citadel. Shepard has the option to rekindle their relationship at this time.

If Shepard does not help Grissom Academy in time, she will appear as a special enemy Phantom when Shepard raids Cerberus Headquarters.

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 battle 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, "After this is over, I'm getting laid."

If Jack did not survive the events of the Collector Attacks, 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.

Trivia

 * 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, which became somewhat notorious.
 * If Shepard had casual sex with her, that ends the dialog path, with Jack no longer interested in conversation, or play, if Shepard sides with Miranda during her argument with Jack, or if he breaks off their relationship, Shepard will not be able to converse with Jack and she will retort with "Fuck off!" when she is approached.
 * 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.
 * 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.
 * 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".
 * 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.
 * As with all squad members, Jack has unique dialogue that can be heard at various locations, during missions or assignments, or if a specific squad member is in the selected team.
 * The Shadow Broker has files on Jack which can be accessed aboard his ship.
 * 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.