Who is Grace from Sarah Kane: Complete Plays and what is their importance?

Grace is the protagonist of "Cleansed". She comes to the university/concentration camp when her brother Graham dies. Meeting with Tinker, she demands Graham's clothes. Tinker gives them to her - taking them from the boy Robin - and sedates her. When she wakes up in the camp, she is kept company by her brother Graham. He watches over her for the play, helping her through the beatings, rapes, torment, and electroshock Tinker forces on her. Grace, while incarcerated in the camp, tries to teach Robin how to read, but he develops an infatuation with her. She continuously and gently rejects him, and after she is lobotomized with electroshock, Robin kills himself. Grace finally is transformed into Graham after Tinker removes her breasts and vagina and attaches Carl's penis to her. The play ends with Grace/Graham and Carl comforting each other.