I just thought of a new quirk to my character. Although the body remains the same, there could be twelve souls stored in the sword that can inhabit it. This is represented by her body being the executioner, the sword being the judge, and the 12 souls being the jury. The souls will be able to recharge themselves after being defeated and hiding back in the sword. However, they can't recharge in a single battle. A new soul could only enter her body if the sword is stabbed into the corpse, so as long as you can avoid that she won't keep coming back for you.