Mid-childa native, private 1st class with a mage rank of "B". Subaru was rescued from from a burning airport by Nanoha four years prior. This inicident inspired Subaru to join the armed forces with aspirations of becoming a powerful mage. By chance she was transfered into Mobile Section Six's Stars squad commanded by the very same person who rescued her. On the field, she is equipped with the rollerblade-like intelligent device Mach Caliber and the armed device Revolver Knuckle.
Like her sister Ginga she is actually a cyborg created on base of genetical material of Quint Nakajima