Marin

was one of Yuuji Kazami's "classmates" at Heath Oslo's child terrorist training school.

History
Marin had no memories of her past before entering Oslo's training school. Yuuji described her as the one person he possibly considered a "friend" in that school. She was the only person who was sympathetic to Yuuji, from treating his wounds when he was injured in a training session to setting aside some of her food when he was forced to go without dinner.

When both Yuuji and Marin were ready to graduate from the training school, the two of them were forced to fight to the death in hand-to-hand combat, the winner being the only one who would graduate. Marin spent most of the fight in a frenzy from the drugs she was given, making moves against Yuuji that he was easily able to deflect. Marin was losing the fight and close to death, when her opponent froze up and stopped fighting altogether. She took this opportunity to turn the fight around and beat him mercilessly.

When Yuuji was brought to the school's underground "treatment facility", Marin went to visit him after regaining her sanity, where she apologized and treated his wounds once more. She continued these visits for a number of days. During her visits, she revealed to Yuuji that she would be graduating soon.

After graduating, Marin was used as a female test subject for Project Typhon. She was impregnated with Yuuji's genes and used as a vessel for one of the artificial solders. Sometime during the experiments, she escaped. Oslo ordered her to be tracked down so the location of the testing facility would not be revealed to the public. She was gunned down, but the fetus inside of her body survived. That fetus, experiment number TP-427, would later be known as Typhon. When he first asked about her post-graduation whereabouts, Yuuji was informed that she made a "stupid mistake" on her first "job".