As a teenager, she was caught breaking into the lab of Dr. Mann's father, who then arranged for her to receive training in the martial arts from The Perfect Circle, an organization formed in the 1940s by Emperor Hirohito as a countermeasure to the Culper Ring. In the "Motherland" arc, she reveals that one of the reasons she stays in Dr. M/Dr. Matsumori's employment is so she would be given a long line of clones, thus "(she) would never really die."
A teenager who broke into a lab, trained in martial arts by The Perfect Circle, seeking immortality through cloning.