Girl is a character who appears only briefly in The Price of Neutrality. She can be found with the cook near the campfire, north of the Camp, but initially will not speak to the witcher. Only after Geralt leaves the camp the first times does she take him aside to plead with him to kill Deidre, whom she considers a monster.
She then relates a story which tells of how she and her mother were forced by Deidre herself to watch as the princess and her armed band slowly and cruelly tortured her father to death.
Though this character is named "Girl", she is obviously an adult.