- Emmanuelle Sharon: "You lack discipline."
- Justine Marsters: "I can't sit, bark or fetch, but breaking out of a prison filled with vicious predatory bitches? I could do that in my sleep!"
- ―Emmanuelle Sharon and Justine Marsters, while imprisoned by the lirrax.[src]
Justine Marsters is a former Infiltrator in the Alliance Military, currently serving aboard the NCSV Arine as part of a prison sentence. After being the only known survivor of a unit killed at Marile and then becoming one of the few survivors of a unit that took heavy losses at Torfan, she has gained a reputation for being able to survive anything, a reputation that was tested when she was imprisoned at the notorious L'Shero Correctional Station and then captured during a jailbreak by the predatory lirrax.
The only daughter of Admiral Robert Marsters, Justine spent the bulk of her childhood aboard space stations. Her father was revered for his service during the First Contact War, and was a proud member of the Terra Firma Party and an investor in the Ceres-Berman United Security, a highly successful private contractor known for its pro-human policies. The years were not kind to the admiral, however, and he watched as the Alliance turned towards galactic integration and distanced itself from those with his politics. He became a cantankerous old recluse, and as his charisma faded, even Terra Firma turned its back on him. Justine has never really talked about what is was like to live with the Admiral, but as soon as she was old enough, she left home and joined the Alliance Navy. She never saw the old man again; he was killed in a car accident less than a year later.
As the daughter of a well-known admiral, Justine had certain expectations placed upon her. She almost completely failed to meet those expectations, and was noted for clashing with her immediate superiors. Her career took a turn for the worse at Marile, an arid terrestrial planet where her unit had been deployed to eliminate a Blue Suns stronghold. During the mission, their convoy was set upon by operatives of Cerberus, the pro-human extremist group. Every one of Justine's squadmates were killed, but Justine herself managed to hold her own against the attackers. They finally subdued her, but not before she had killed half of them.
After being incapacitated, Justine was taken to a nearby base, where she was tortured for information. Upon learning that she was the daughter of Adm. Marsters, her captors decided to release her, but told her that one day, they would return and demand a favor. She was then returned to the scene of the ambush, which had since been altered to give the impression that her unit had been killed by a Thresher Maw.
Marsters was eventually posted to another unit, but bad luck seemed to continue to follow her, as her unit was sent to Torfan, where they suffered heavy losses at the hands of batarian pirates. Though Marsters herself did nothing wrong, she earned a reputation as an albatross, and others refused to fight alongside her. Her commanding officer put her on leave, stating that after two traumatic incidents, she was at risk for potential mental illness.
Frustrated with her less-than-stellar career, Marsters spent much of her leave on the asari world Tamaris. One night, while intoxicated, she got into a fight with one of the locals and accidentally killed them. She pled guilty to manslaughter and was sentenced to serve time at nearby L'Shero Correctional Station.