Shiho Miyano, codenamed Sherry, was born into the criminal Black Organization. Her parents, scientists Atsushi and Elena Miyano working for the organization, died in an alleged accident during her childhood. Shiho and her older sister Akemi were raised within the organization, though Akemi lived relatively normally while Shiho was groomed for scientific work. Sent young to the United States for education, she experienced social isolation. By thirteen, she became the lead researcher continuing her parents' work on the experimental drug APTX 4869. Her codename Sherry, derived from the alcoholic beverage, followed organizational convention. At eighteen, Shiho developed the current APTX 4869 formula. Intended as an undetectable poison, she discovered its rare de-aging side effect after observing a lab mouse and withheld this knowledge. Unbeknownst to her, the organization began human trials for assassinations. During these, Shinichi Kudo ingested the drug and shrank. Finding evidence suggesting his survival during a home search, Shiho falsified his status as deceased to protect him. She disapproved of the drug's use for murder but continued research under duress. Following her sister Akemi's murder by high-ranking member Gin, Shiho rebelled by halting her research. The organization imprisoned her to await execution. To escape, she ingested a hidden APTX pill intending suicide but instead shrank to a child's size. Slipping free, she fled through a garbage chute and collapsed near Professor Agasa's residence. Agasa discovered her, providing shelter and helping her assume the alias Ai Haibara. As Ai Haibara, she enrolled at Teitan Elementary School, joining Conan Edogawa (Shinichi Kudo's alias) and the Detective Boys. Initially cynical and distrustful, she prioritized self-preservation over idealism. She maintained emotional distance, particularly avoiding Ran Mouri due to Ran's resemblance to Akemi. Overtures from the Detective Boys and Ran gradually softened her demeanor. She developed genuine friendships and became more open to Conan's pursuit of justice. Despite valuing these connections, she viewed herself as a danger, fearing the organization would eliminate anyone associated with her if discovered. Her personality retained contradictions—regretting the drug's misuse yet having been prepared to test it lethally. She spoke formally and maintained a reserved, observant demeanor. Haibara possesses exceptional biochemical expertise, enabling her to develop APTX 4869 and work on temporary antidotes. Destruction of the organization's research data significantly slowed antidote progress. She demonstrates acute medical knowledge, diagnosing conditions like subdural hematomas, and forensic skills, such as deducing mobility from skeletal remains. Her deductive abilities approach Conan's, though she lacks his specialized knowledge and often remains quiet during investigations to avoid attention. She exhibits a unique "Black Organization sense," detecting members' presence as a distinct "pressure" or "smell," inconsistently triggered. Haibara tolerates extreme pain, evidenced during her de-aging escape and later injuries while temporarily reverting to adulthood. She is proficient with firearms and can drive vehicles, having owned a Harley-Davidson as Shiho. Haibara lives under Professor Agasa's guardianship, sharing a bond built on mutual scientific interest. She often acts as his caretaker, monitoring his diet. Her relationship with Conan evolved from mutual distrust to deep trust; she deduced his identity early and collaborates closely. Though she once harbored romantic feelings for him, these shifted into profound admiration for his resilience. She dissuaded him from revealing his identity to Ran, emphasizing secrecy's importance. Haibara views Ran as a sister figure, a sentiment reciprocated when Ran risked her life protecting her. She is a cousin to Shuichi Akai, Shukichi Haneda, and Masumi Sera through her aunt Mary Sera. Her most feared pursuers are Gin, who killed Akemi, and Vermouth, who harbors intense hatred toward her and attempted to kill her with explosives during the Bell Tree Express incident. Vermouth's knowledge of Haibara's de-aging remains concealed from the wider organization. Haibara collaborates with Conan to develop APTX 4869 antidotes, using temporary versions when necessary. The organization, believing Sherry dead after the train incident, continues hunting her. She participates in Detective Boys cases, balancing her secret life with school activities. Personal interests include high fashion brands like Fusae and Prada, peanut butter and blueberry jelly sandwiches from her American time, and idolizing footballer Ryusuke Higo. She reads mystery novels like Agatha Christie's Hercule Poirot series. Her alias "Ai Haibara" derives from literary sources: "Haibara" from Cordelia Gray's surname (meaning "ash"), and "Ai" from V.I. Warshawski. She chose the kanji for "sorrow" over Agasa's suggestion of "love."