I don't have a name for her yet, she's a meister though. That soul she's holding is the soul of a ghost that follows her around. Ghost was a scythe weapon, and pitches a fit if she tries to use any other weapons. For some reason he's taken a real liking to her and haunts her like crazy. She's 15, and a little bit sadistic. She doesn't know why Ghost follows her around, and why she can use him as a weapon, but she keeps looking for a partner to piss him off. She doesn't just outright kill kishin, she plays with them if she gets the chance, and drags out killing them. She's not as messed up as Stein, she's just cruel.
If you can think of a good name for her, then you get a cookie
EDITXXX Her name is now Mellanie, courtesy of