Chihiro Ayasato, known internationally as Mia Fey, was a defense attorney defined by her unshakeable belief in her clients. She began her career at the Hoshikage Law Offices, known as Grossberg Law Offices in some regions, before founding her own criminal defense practice, Ayasato Law Offices, or Fey & Co. Law Offices. Born into the prominent Ayasato family, a lineage of spirit mediums also called the Fey clan, Chihiro grew up amidst a rivalry between her mother, Misty Ayasato, and her aunt, Morgan Ayasato, over the position of Master of Kurain Village. She maintained a close relationship with her younger sister Mayoi, also known as Maya Fey. In their childhood, the two sisters were involved in an incident where they attempted to piece together the Sacred Urn of Ami Ayasato. A pivotal event occurred with the murder of defense attorney Gregory Edgeworth. With no other clues, the police had Misty Ayasato channel the victim, who identified Yanni Yogi as the killer. Yogi was later found not criminally responsible in court. The incident disgraced the Kurain tradition, and Misty, deemed a fraud, disappeared. Years later, Chihiro left Kurain Village, forsaking her position as heir, to become a lawyer and uncover the truth behind the DL-6 Incident and her mother's disappearance. It was also suggested she wished to avoid a similar rivalry with her sister. She left Mayoi under the care of her aunt Morgan and Morgan's daughter, Harumi. Although she left the life of a spirit medium, Chihiro continued to wear a magatama. During law school, she befriended Lana Skye, who would later become a police detective and Chief Prosecutor. After graduating, she worked under defense attorney Marvin Grossberg. She eventually discovered that Grossberg had sold information about her mother's involvement in the DL-6 Incident to Masaru Konaka, also known as Redd White, who subsequently leaked it to the press. Her first case was defending escaped convict Terry Fawles, accused of murdering Police Sergeant Valerie Hawthorne. Her co-counsel was Diego Armando, also known as Soryu Kaminogi or Godot, and the prosecutor was Miles Edgeworth. During the trial, Chihiro proved the alleged eyewitness "Melissa Foster" was actually Dahlia Hawthorne and attempted to prove she was the real killer. Fawles, however, committed suicide in court by drinking poison. The case emotionally scarred Chihiro, and she did not take another case for over a year. She and Armando became a couple, and he began investigating Dahlia Hawthorne. During an interview, Dahlia poisoned Armando's coffee; he survived but fell into a coma. Chihiro eventually returned to the courtroom to defend university student Ryuuichi Naruhodo, also known as Phoenix Wright, who was charged with murder. She took the case suspecting a connection to Armando's poisoning. She secured Ryuuichi's acquittal by proving Dahlia Hawthorne was the true culprit, an act that shattered the confidence of the prosecutor, Winston Payne. Hawthorne was later convicted and sentenced to death for her crime. Over the next three years, Chihiro established her own law firm and hired her former client, Ryuuichi Naruhodo. She gathered extensive information on Masaru Konaka and the DL-6 Incident, uncovering a career of blackmail. She enlisted her sister Mayoi's help to safeguard evidence and instructed her to contact Grossberg if she ever needed a lawyer. One month after Ryuuichi's first trial, Masaru Konaka learned of Chihiro's investigation. He visited her law offices and killed her with a clock statue, in which she had been hiding legal documentation against him. As she lay dying, Konaka used her blood to write "Mayoi" on a receipt for a lamp to frame her sister. An accomplice, April May, falsely witnessed the crime. Detective Keisuke Itonokogiri, also known as Dick Gumshoe, discovered Mayoi and Ryuuichi at the scene and arrested Mayoi for the murder. Ryuuichi took Mayoi's case and exposed April May as an accomplice in court. He investigated further, learned of Chihiro's investigation into Konaka, and confronted him, only to be arrested himself after Konaka used his blackmail connections. Konaka then stood in court as a witness. When the situation seemed hopeless, Mayoi channeled Chihiro's spirit. Chihiro instructed Ryuuichi to examine the other side of the blood-stained lamp receipt, the date on which refuted Konaka's claim about when he had seen the lamp. When the prosecutor persisted, Chihiro began reading a list of Konaka's blackmail victims, threatening to release it to the press, which forced Konaka to confess to the murder. Following her death, Chihiro continued to assist Ryuuichi through spirit channeling performed by her sister Mayoi or their cousin Harumi Ayasato, also known as Pearl Fey. This assistance included helping with investigations, such as persuading a witness to testify, and providing crucial guidance and reminders during difficult trials. This support was instrumental in solving cases, including those related to the DL-6 Incident and plots orchestrated by her aunt Morgan against Mayoi. On one occasion, when Mayoi was kidnapped, she and Harumi communicated by channeling Chihiro to aid the search efforts while Ryuuichi worked to secure the kidnapper's client a guilty verdict to ensure Mayoi's safe release.