Who is the main character in the story, Heartless, from the collection, Young Warriors: Stories of Strength?

Ada, the story's main character, is an orphaned hedge witch who survives war by robbing dead bodies on the battlefield. Her mother placed a spell on Ada so that she would no longer feel pain, fear or sorrow. However, she can't feel love either. Ada feels nothing in life and learns that being numb to life and emotions is not truly living. She wears a piece of her petrified heart around her neck.