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.
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.
Following the Collector mission, the Alliance offered her a choice, be sent to prison or became a teacher in a Alliance controlled Academy, she choose the latter. She is now a successful teacher who have now repeatedly showed to care for her students and willing to attack anyone who treatings them