Ami Mizuno, known as Sailor Mercury, stands as the Guardian of Water and Wisdom. Her civilian life revolves around exceptional intellect, consistently achieving top national exam scores. This academic drive stems from aspirations to become a physician, though peers often misinterpret her shyness as arrogance, leading to social isolation. Her parents' divorce resulted in living primarily with her work-focused mother, Saeko Mizuno, a respected doctor, while maintaining distant contact with her artist father. Alongside her studious nature, she harbors secret interests in romance novels and pop culture. Luna recruited Ami after detecting unusual energy around her. During a confrontation with a Dark Kingdom operative at Crystal Seminar, where brainwashed students used cheating devices, Ami resisted and awakened as Sailor Mercury. Her first transformation employed the phrase "Mercury Power, Make Up," unlocking abilities focused on water manipulation, primarily creating concealing mist (Shabon Spray), and utilizing analytical gadgets like the Mercury Computer and Goggles for tactical support, cementing her role as the team's strategist. Character development saw Ami transition from insecurity to confidence through friendships, particularly with Usagi Tsukino. She remains the most reserved and conflict-averse Guardian, yet her analytical skills prove crucial in battles, often identifying enemy weaknesses. Loyalty to Sailor Moon is absolute, leading to sacrificial acts like perishing against the DD Girls to extinguish fires threatening civilians. Resurrections followed major victories, such as the defeat of the Dark Kingdom, though accompanied by temporary memory loss. Romantic elements appear sparingly. The anime introduced Ryo Urawa, a psychic student surpassing her academically through unnatural means; they shared mutual affection before his departure. The manga side story "Ami's First Love" featured an academic rivalry and potential attraction to a boy named Mercurius, complicated by a psychosomatic allergy to love letters causing rashes. Other media, like the live-action series, depicted brief connections, such as pity for Nephrite while brainwashed as "Dark Mercury." Powers evolved significantly. Initially defensive and tactical, abilities expanded to include offensive techniques like Shabon Spray Freezing in the Black Moon arc, directly immobilizing enemies. Transformations reflected growing strength: Super Sailor Mercury, achieved during conflict with the Death Busters, featured uniform changes like a heart-shaped brooch and enhanced hydrokinetic/cryokinetic attacks such as Mercury Aqua Mirage. The Eternal form, gained in the manga/Cosmos films, introduced further uniform alterations like star motifs and sleeves, signifying peak power. Key story moments include nearly accepting a study abroad opportunity in Germany for medical studies, only to renounce it upon realizing her indispensable role with the Guardians, returning just in time to defeat an enemy vulnerable to ice. During Sailor Moon S, her persuasive intervention prevented Sailor Uranus and Neptune from killing Hotaru Tomoe. The live-action series uniquely explored familial pressure regarding her career path and depicted brainwashing by Kunzite into "Dark Mercury," weaponizing feelings of inadequacy. Future iterations place her residing in Crystal Tokyo during the 30th century alongside Neo-Queen Serenity, acting as a "Barrier Maiden" protecting the city. The non-canonical "Parallel Sailor Moon" story depicted marriage, motherhood to a daughter also named Ami, and a career as a doctor under financial strain.