|“||Turns out, mess with someone's head enough, you can turn a scared little kid into an all-powerful bitch. F*cking idiots.||„|
Jack (also known Subject Zero, real first name Jennifer) is one of the many characters in the Mass Effect franchise. She is recruited for Shepard's team in the second game, and makes an appearance in the third game.
She is voiced by Courtenay Taylor, who also voiced Nora.
Mass Effect 2
Jack was test one as a child by Cerberus, an antagonizing organization in the games. She eventually grew stronger, and eventually Shepard and friends help her escape out of a prison, and then she joins the Normandy.
Mass Effect 3
In Mass Effect 3 (if she survives Mass Effect 2) she is a teacher of a group of teenage biotics, and Shepard helps her on a mission. She makes other appearances, and is able to be spoken to before the final assault.
As a direct consequence of the horrors she endured as a child, Jack is (at least initially), a violent, bloodthirsty, aggressive, cynical, misanthropic, and homicidal individual. Filled with rage and hatred in general and for all things Cerberus in particular, Jack greatly enjoys violence, reveling in the destruction she causes and looking back fondly on some of her more high-profile crimes, such as taking out a moon important to the Hanar. She also expresses admiration and respect for other people's acts of ruthlessness (with the exception of Cerberus), as if Shepard takes a renegade interrupt to blast or push a mercenary out a window to his death during Thane Krios' recruitment mission, Jack will note that she should "take notes from him". Jack even, if pressed, admits that she does actually enjoy the power Cerberus gave her despite hating them for abusing and torturing her to do so.
However, if Shepard takes the time to get to know Jack, they quickly discover that Jack is incredibly bitter and unhappy as a person, still haunted by her past abuse by Cerberus and others and sustaining herself on near-constant hatred and rage. If shown compassion and understanding, Jack gradually mellows and cools down, and if romanced dares to show a softer side still with Shepard, crying and finally allowing herself to, in Liara T'Soni's words, "have faith in something besides anger".
Mean-spirited and cynical most of the time, Jack has little use for sentiment or lofty ideals, though she does have a hidden talent for poetry, again indicating that a softer side to her does exist, even if it is well-hidden. She can also be incredibly selfish, as though she hates Cerberus for their abuse of her, she has no empathy or concern for the other children at the facility who suffered alongside her, having indiscriminately killed them as well as Cerberus personnel when she made her escape from the facility and never expressing any sorrow or pity for them. Even when confronted with a fellow grown-up survivor of the atrocity, Jack is hesitant to fully admit that the other children did, in fact, have it bad as she did, her admission being reluctant and non-commital in tone. This indicates that, while a tragic figure, Jack is nevertheless also (at least initially), a self-centered one, caring only about her own suffering and pain but not anyone else's.
Due to her past with the organization, Jack is deeply hostile and contemptuous of all things Cerberus, whether they had any hand in her tragedy or not. In particular she loathes Miranda, deriding her as a "Cerberus cheerleader" and sniping at and baiting her regularly, as well as later threatening to kill her and calling her a "bitch". Though the two are able to work together reasonably effectively, and Miranda seems to be saddened by Jack's death during the Suicide Mission if she dies, the two are not friends. Even by the time of Mass Effect 3, if they are both still alive, the two continue to needle each-other (albeit now with far less hatred behind it).
Jack can frequently be immature and petty, exhibiting characteristics of an angry teenager or even a child. This is likely due to her having been denied a proper childhood and with it, proper emotional development. Jack not only takes an almost child-like joy in destruction and has poor impulse control, she also frequently lashes out and rages when she does not get what she wants, such as if Shepard takes Miranda's side over her's in an argument, at which point Jack refuses to talk to anyone on the ship for the remainder of the game unless Shepard later convinces her that they didn't mean what they said. Jack is also incredibly foul-mouthed, swearing constantly and in particular using the f-word regularly. This tendency is such that, should Jack be alive in Mass Effect 3, Joker will mockingly ask if Jack keeps a swear jar.
By the time of Mass Effect 3, Jack has mellowed significantly, the positive atmosphere of Grissom Academy giving Jack a sense of belonging and contentment she hasn't ever known before. As such, she is far less irritable and violent than before, having largely matured and become a mostly level-headed teacher who is respected and liked by her students.