Ai Haibara, born Shiho Miyano and formerly known as the Black Organization operative Sherry, stands as a central franchise figure. Orphaned young after her scientist parents, Elena and Atsushi Miyano—also organization affiliates—died in an incident officially deemed accidental, she was raised within the organization alongside her older sister, Akemi Miyano, who was later executed by their employers. A chemistry prodigy, Shiho received overseas education sponsored by the organization before returning to Japan to inherit her parents' research on the "Silver Bullet" project. By thirteen, she led the development of the APTX 4869 toxin, designed as an untraceable poison. During testing, she observed one mouse de-age instead of dying but concealed this anomaly. The organization deployed APTX 4869 for assassinations, including targeting Shinichi Kudo, who subsequently shrank into a child's form. Later, while searching Shinichi's home, Shiho noted his childhood clothes missing and deliberately confirmed his "deceased" status to protect him. Following Akemi's death, Shiho rebelled, resulting in her imprisonment. Choosing suicide, she ingested APTX 4869 but de-aged instead, escaping confinement through a garbage chute. She collapsed near Shinichi's residence, where Professor Hiroshi Agasa discovered and sheltered her. Adopting the alias "Ai Haibara" for concealment, she drew the name from literary sources: "Haibara" (translating "Gray" from "Cordelia Gray") and "Ai" (inspired by "V.I. Warshawski" or Sherlock Holmes' Irene Adler). She enrolled at Teitan Elementary School alongside the shrunken Shinichi, now Conan Edogawa, joining his Detective Boys group. Trauma initially shaped Haibara into a cynical, detached persona, but bonds gradually formed with Conan, the Detective Boys, and Ran Mouri. She remains deeply haunted by the Black Organization, exhibiting acute sensitivity to members like Gin and Vermouth. Despite her child's body, she retains her adult intellect, frequently aiding Conan with scientific expertise and case analysis. She works tirelessly to develop an APTX 4869 antidote, though progress is hampered by destroyed research data. Temporary antidotes, sometimes involving baijiu, allow brief reversions to her adult form. Haibara's personality merges stoicism, sarcasm, and latent compassion. Her mature speech and unexpected knowledge—spanning theology, history, and forensics—often surprise peers. Protective instincts drive frequent self-sacrificial attempts to shield friends from the organization, such as staying on a bomb-rigged bus or nearly surrendering to Vermouth. She values animals, maintains a keen interest in fashion (favoring brands like Prada and Fusae, and reading "ComCom" magazine), idolizes soccer player Ryusuke Higo (relating to his betrayal of a corrupt team), and enjoys Yoko Okino's music. In "The Bride of Halloween," Haibara witnesses a bombing near Tokyo Metropolitan Police headquarters. A foreign man drops a bloodstained tablet; she retrieves a fallen paper for him, but the tablet explodes, throwing her into traffic. Kogoro Mouri saves her but suffers critical injuries from a truck. The man, later identified as Oleg Lavrentyev, died instantly; Haibara recalled his Russian accent. This event connects to a wider conspiracy involving a serial bomber and the group "Plamya." Haibara's familial ties extend to the Akai family: her aunt Mary Sera (Elena's sister) makes Shuichi Akai, Shukichi Haneda, and Masumi Sera her cousins. These connections, revealed over time, add depth to her backstory and motivations. Across numerous cases, Haibara's resilience emerges. Key arcs involve her initial identity revelation to Conan, confrontations with the Black Organization (including the Pisco incident), and efforts to protect Conan's secret—once impersonating him while he temporarily reverted to Shinichi to dispel Ran Mouri's suspicions. Her journey reflects a shift from isolation towards tentative integration into normal life, persistently prioritizing others' safety over her own.