that's a female demon that enchants men (which would also go along with the story well as a street name for the character) but I was thinking along the lines of stealing other people's lives by combining them with your own.
~~
their personality could be altered as the story goes on, making them go through an identity crisis, and have them eventually lose their mind before killing themselves
~~
their personality could be altered as the story goes on, making them go through an identity crisis, and have them eventually lose their mind before killing themselves