Born with a rare genetic condition where she had six fingers on her left hand, Alison Wears was a chemical engineer for the Ace Chemicals, which resulted in her getting a chlorine-based chemical burn on her left thigh. In addition, she also underwent surgery at one point to remove a cancerous growth severe enough to require her to use a voice box. Eventually she was put into a retirement home in Blüdhaven next to a park. It was near this park that she ended up abducted by the Circus of the Strange.
Upon being brought to Gotham City, she was experimented on by the leader of the Circus of the Strange, Professor Pyg. As her flaws were too severe for even him to fix, she instead ended up murdered via an overdose of painkillers, as well as having her fingerprints destroyed by acid. She was then placed at an alley at Waypoint, with the words "Rejected" posted nearby as well as opera music blaring loudly.
Batman eventually found her body when trying to solve a chain of related murders. He managed to identify her via anomalies in her system and cross-referencing them to people reported missing, because her DNA was too corrupted and damaged for her to identify directly via DNA analysis.