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. Her genetic memories were later used as an Animi Avatar by the Templar company Abstergo Industries, for the training of their Animus recruits, under the title of the Thief.