Ai Haibara was born Shiho Miyano within the criminal Black Organization. Her parents, scientists Atsushi and Elena Miyano, worked on the clandestine Silver Bullet project before dying in an alleged accident. A child prodigy, Shiho was sent to the United States for education and later returned to Japan to continue her parents’ research. By age thirteen, she served the organization under the codename Sherry. At eighteen, she engineered the drug APTX 4869, initially developed as an untraceable poison. During testing, she observed a rare de-aging effect in a mouse but withheld this finding. After the organization executed her sister Akemi Miyano, Shiho rebelled, sabotaged her research, and was imprisoned and sentenced to death. She ingested APTX 4869 to commit suicide but instead regressed into childhood, escaping through a laundry chute. Found near Shinichi Kudo’s home by Professor Hiroshi Agasa, who knew her parents but not their organizational ties, she adopted the alias Ai Haibara. The surname translates to ash field, while Ai uses the kanji for sorrow. As Ai Haibara, she enrolled at Teitan Elementary School and joined the Detective Boys alongside Shinichi’s shrunken identity, Conan Edogawa. Initially guarded and cynical, she confessed her true identity and role in creating APTX 4869 to Conan, and over time she grew to trust him and the Detective Boys as her first true friends. She works on developing an antidote using fragmented data after most of her research was destroyed. Fearful of the Black Organization, especially operatives Gin and Vermouth, she considers herself a danger to others. Haibara displays a calm, analytical demeanor laced with sarcasm, with expertise spanning science, history, and theology. She is fond of peanut butter and blueberry jelly sandwiches from her years in the United States, covets luxury brands like Prada and Fusae, and admires soccer player Ryusuke Higo, relating to his departure from a black organization called Noir Tokyo. Key events include Vermouth uncovering her identity, resolved by a temporary ceasefire, and later an assassination attempt aboard the Mystery Train, where Conan and allies staged her death in an explosion, convincing most of the organization that she died; only Vermouth deduced her survival and kept it secret. Her familial connections include aunt Mary Sera and cousins Shuichi Akai, Masumi Sera, and Shukichi Haneda. In the Magic File 4 episode The Osaka Okonomiyaki Odyssey, she travels to Osaka with the Detective Boys, Conan, and Professor Agasa, providing quiet support as the group seeks an okonomiyaki restaurant.