Faustina Collari was a Romanthief during the Renaissance. She was born into hardship, and was forced to steal in order to survive.
Being so close with her brother, she promised to protect him with her life, just as he protected her. Due to them depending on each other in this way, the bond between the two of them was great enough that they split a pair of scissors, to create matching weapons for them to use. However, at one point, Faustina's promise to her brother was broken, and he was lost.