Vivian

Vivian (more commonly Vivi) is a four armed assassin who was originally hired by Inspector Gentile to murder Akazukin. During their fight she realized she couldn't defeat Akazukin, so she instead decides to join forces with her. She takes up residence at Marco's butcher shop and accompanies Akazukin on body hunting missions. She notes that before she met Akazukin no one has ever laid eyes on her four arms. Vivi also boasts a never fail record as an assassin, although that was before she fought Akazukin. She's referred to as an "artifact" by other worldly beings. The title "artifact" is given to certain people who were failed experiments in creating an artificial host for the being Mr. Wolf.