The Girl was created by cowriters Gerard Way and Shaun Simon, and artist Becky Cloonan. She is a prominent character in The True Lives of the Fabulous Killjoys, published by Dark Horse. The series is the sequel to a story described in the My Chemical Romance album, Danger Days: The True Lives of the Fabulous Killjoys.
In the dystopian storyworld in which the series is set, the Girl's mother was a freedom fighter during the Analog Wars. However, she was captured by B.L.I. (Better Living Industries), presumably by Scarecrow Korse. However, the mother gives birth to the Girl.
The Girl's mother's allies, the Killjoys, apparently raise the Girl as one of their own, but eventually she is retaken by B.L.I. The Killjoys are killed in an attempt to rescue her from B.L.I. clutches, except for Cherri Cola and the Girl herself. For his part, Cola and Killjoy ally, Dr. Death Defying, attempt to use rhetoric rather than violence to resist Better Living Industries. Meanwhile, B.L.I. arranges for the Girl to find a cat in the desert which is actually a tracking device to keep tabs on her.
Near the remains of Destroya, the Girl encounters a group of Killjoy wannabes led by Val Velocity. Velocity is extremely brash, and seems to have little regard for the legacy of the Killjoys. The Girl is also reunited with Cherri Cola. She discovers Dr. Death-Defying dead, and immediately establishes that Val Velocity is the killer.
Val Velocity leads an attack on Battery City, and the Girl reluctantly follows, the only person aware of the murder Velocity has committed. After she and Cola are apparently gunned down in the ensuing battle, the Girl's disembodied spirit is found by the Phoenix Witch. The Witch discloses the Girl's origins to her, and makes her consider how best to use her powers. The Girl regains consciousness and cuts her hair and arms herself.