Yes, Gracie is a princess, no she is not evil. She is about 17 in this picture, and this is what she wears when she wants to be stealthy. She has her father's katana in this picture. The mask is to hide her identity.
Older Gracie: Dad, i don't want to be a princess. I am, but i don't want to. I want to be free, to do as i please. I want to be a warrior, a fighter, a problem solver. I want to help people, not sit there in a dress and pout about being bored. I want to be a winner, a winner for others. I want to help the people who can't help themselves...