Murderess first appears to be a very selfish and greedy individual who will stop at nothing to gain more wealth. She has gained a reputation for double crossing her fellow BLADE members just to claim the entirety of a mission's reward for herself, and often manipulates other BLADE members into doing her bidding. She also tends to draw the ire of Irina, though the two later reconcile and become friends. She is revealed to be Sharon Effinger, a girl from a rich family whose parents were slain when she was young. She discloses that her ultimate goal is to restore the Effinger name on Mira and honor her murdered parents. Though she does not actually kill anyone, she uses the alias "Murderess" to remind herself that she would someday avenge her parents.