"Or send a person over the edge causing pain and suffering to those around them," Briallen whispered sadly. At Hermione questioning look, she explained, "Director Croaker told me what happened to Sally-Anne while we were in the infirmary. She was...changed. He said that someone used some kind of dark magic to turn her into a sleeper agent assassin. That’s why she’d been acting strangely around me. She had orders to kill me but she resisted. Resisted long enough that it started affecting who she was and caused others to notice and seek help.