Kasuto Toshibara was full of surprises, dubbed the mystery girl. When she enrolls in the DWMA, with her weapon Hiro, there is a certain group of people that just so happen to unravel her story. Kasuto is a 16 year-old girl, and is a prodigy. She excels at martial arts, weapon combat, and just about everything a Meister should know. Her one weakness, opening up. She doesn't know who her parents are, and has lived with Lord Death and his son since she can remember. She stays away from school, knowing that she will be deemed an outcast. She was home-schooled by Kid, and trained by herself. A lone wolf in a world full of people who wanted to shoot her down.