Little is known about Beatrix's past, save that she grew up in a middle-class family in the city of Treno. Visits to Alexandria led her to like the city. After her 16th birthday, she decided to move to Alexandria and join the all-female Alexandrian army. This led to years of battle and intense training allowing her to become a captain and, eventually, a general heading the Alexandrian Army. During this time, she became acquainted with the head of the Knights of Pluto, Captain Adelbert Steiner.