Marla Janssen was born in the Scandinavian sector of Earth, but when she was just ten years old, her father took a job on Mars and moved his family there. Already somewhat bookish, Marla became a recluse in this literal alien environment. She spent all of her spare time and money on computer tech which was an area that she excelled in at school along with Math and Physics.
When she was thirteen, Marla's parents became suspicious that their daughter seemed to have a lot more money than her weekend job that they should have been able to pay. Their investigations unfortunately led to involvement by the police and within weeks, Marla became the youngest person on Mars to ever be arrested for 'Grade 1' hacking. She was taking orders and payment from anonymous clients on the net, hacking into the central government's database to alter records for these clients.
Three years in Mars juvenile prison put Marla on the straight and narrow. She was released. Her record was sealed and on her sixteenth birthday, she promptly began working in the Mars shipyards as a systems designer and QA officer. While there, she met Bram Neumann while he was on leave to visit his wife. He told Marla that she could earn more and have an easier life with P-Sec, whom he just happened to know that they are looking for a new control op on Commander James' squad.
Marla followed up on the lead and within days, she was offered the job. Marla since worked on two colonies with James' squad. Since his divorce, she and Neumann developed a casual relationship.
The Second Aegis VII Incident
It was implied that she and Abraham Neumann are in a relationship. She had an interest in Unitology and the Marker for mostly secular reasons. She devised that the markings on it are a code for DNA and it infected dead bodies, mutating them. Throughout several of the comics, she was seen steadily working on deciphering the text on the Marker while Neumann joked about her luck at it since the Church had to decipher it. Eventually, Marla discovered the text's meaning.
After the shuttles are destroyed, she came up with a plan to radio up to the USG Ishimura and call for help, bypassing the problem with the communications by heading straight for the communications needle, but upon reaching the needle, she realized that the alien flesh was probably the cause of all of the problems with it and her job would be ten times harder. Upon investigating an open door with Neumann, they discovered a large biomass of Necromorphs on the wall. She shouted at Neumann to snap him out of a gaze that he had on one of the Necromorphs composed of the body of his former partner, Vera Cortez. In the race out of the room, she struggled to reach the door and was impaled through the chest by a Necromorph. In a last act of selflessness, she activated the door lock, much to Neumann's dismay, and sealed herself in with the other Necromorphs, saving Neumann.