Depicted as a martial arts child prodigy, Cassandra Cain is written as a young woman of partly Asian descent who becomes the Batgirl, with the approval of both Batman and Oracle, following her introduction in Batman #567 (1999) as part of the Batman: No Man's Land crossover. Cassandra Cain wears the same Batgirl costume worn by Helena Bertinelli. Raised by assassin David Cain, Cassandra Cain was not taught spoken language, but instead was taught to "read" physical movement. Subsequently, Cain's only form of communication was body language. The parts of the character's brain normally used for speech were trained so Cain could read other people's body language and predict, with uncanny accuracy, their next move. This also caused her brain to develop learning functions different from most, a form of dyslexia that hampers her abilities to read and write.
Despite Cain's disability, author Andersen Gabrych describes the character's unique form of language as the key factor in what makes Cain an excellent detective; the ability to walk into a room and "know" something is wrong based on body language. During the first arc of the Batgirl comic book series entitled Silent Running, Cassandra Cain encounters a psychic who "reprograms" her brain, enabling her to comprehend verbal language, while simultaneously losing the ability to predict movements. This issue is resolved during the second arc of the series, Batgirl: A Knight Alone, when Batgirl encounters the assassin Lady Shiva who agrees to teach her how to predict movement once again. Six years after its debut, DC Comics canceled the Batgirl comic book series with issue #73 (2006), ending with Cain relinquishing her role as Batgirl.
