Ami Mizuno, also known as Sailor Mercury, is a central character whose civilian identity is that of a highly intelligent middle school student. She is renowned for achieving top scores in national exams and possesses an IQ rumored to be 300. With short blue hair and blue eyes, she is occasionally depicted wearing reading glasses. Her typical attire consists of her school uniform or casual wear, often sweaters and skirts in modest, pastel colors. She is the daughter of Saeko Mizuno, a busy doctor, and a painter father. Her parents are divorced, a situation that has impacted her, and she lives with her mother in a condominium. Aspiring to become a doctor like her mother, she dedicates herself to her academic pursuits. Despite her scholarly achievements, she was initially perceived as cold and snobbish by her peers due to her shy and reserved nature, leading to a lonely social life before meeting Usagi Tsukino and the other Sailor Guardians. Her personality is characterized as kind, gentle, loyal, and slightly insecure, though she grows more confident and assertive. She enjoys reading, playing chess, and swimming, and has a secret fondness for romance novels and pop culture. Her favorite subjects are mathematics and science, and she has no least favorite class. Ami is the reincarnation of Sailor Mercury, the Guardian of Wisdom and Water from the ancient Moon Kingdom. She was the second Sailor Guardian recruited by Luna, the black cat advisor, after her Mercury symbol appeared on her forehead during a confrontation with a yoma. Using a transformation pen, she utters phrases like "Mercury Power, Make Up" to assume her Sailor Guardian form. In this form, her uniform is primarily blue and white, featuring a sailor collar, a skirt, a tiara with a blue gem, and boots. Her arsenal includes computerized equipment, such as a visor and a miniature supercomputer, which she uses for data analysis and strategy. Her attacks are water and ice-based, beginning with Shabon Spray, which creates a concealing mist, and Shabon Spray Freezing, which can immobilize enemies. As she grows stronger, she gains more powerful attacks like Shine Aqua Illusion and Mercury Aqua Rhapsody. She undergoes several power-ups that change her uniform, achieving a Super Sailor Mercury form marked by a heart-shaped gem on her chest bow and a star on her choker. Later, she attains an Eternal Sailor Mercury form with a more elaborate design featuring star-shaped gems, longer ribbons, and white boots. A Princess Mercury form also exists, consisting of an elegant blue gown. A significant story arc involves Ami developing a relationship with Ryo Urawa, a psychic and reincarnation of one of the Seven Great Yoma, whom she helps protect from the Dark Kingdom. In a notable act of sacrifice during the first season, she is killed by the DD Girls while using her Shabon Spray to extinguish a fire but is later revived. Her character is further explored when she is offered a chance to study abroad in Germany. She initially accepts, seeing it as an opportunity to pursue her medical dreams, but ultimately chooses to remain in Japan with her friends after reaching the airport. This highlights her internal conflict between her personal ambitions and her loyalty to the Sailor Guardians. Her commitment is further demonstrated when she defies her mother's attempt to transfer her to a different school, asserting that her current life and duties are more important than just studying. Within the team, Ami serves as the strategist and analyst. She uses her intellect and computer skills to assess enemies and devise battle plans, often acting as the voice of reason. Despite her gentle nature, she has proven capable of great courage and determination in battle, standing up to powerful adversaries to protect others.