Michiru Kaiou serves as the civilian identity of Sailor Neptune, a guardian tasked with Solar System protection. Her name, translating to "rising sea king," reflects her dominion over the planet Neptune and the sea. She bears teal hair and deep blue eyes, carrying herself with elegance and sophistication. Her civilian pursuits encompass professional violin performance and painting seascapes. She attends Mugen Academy alongside her partner, Haruka Tenou, later forming an adopted family with Haruka, Setsuna Meiou, and Hotaru Tomoe after Mugen's destruction. As Sailor Neptune, she is the Soldier of Deep Waters and Soldier of Embrace, wielding power drawn from the oceanic planet Neptune. Her abilities include seawater manipulation, tsunami generation, and projecting hypersonic waves via her violin. She commands the Deep Aqua Mirror talisman, which reveals hidden truths, constructs protective shields, and enables astral projection. Her primary attacks are Deep Submerge, Submarine Reflection, and Submarine Violon Tide. Using the Neptune Crystal gifted by Sailor Saturn, she ascends to Super Sailor Neptune, her uniform enhanced by a star-adorned choker and translucent wing-like shoulder pads. Her Eternal form adds knee-length boots and a layered skirt. Michiru awakened independently as a Sailor Guardian, requiring no external guidance. She possesses innate precognition, sensing danger through intuitive phrases like "the sea is stormy." Her partnership with Sailor Uranus forms her core; they share a romantic bond and a tactical philosophy prioritizing the greater good, even at personal sacrifice. Initially agreeing to sacrifice each other if necessary, they ultimately choose mutual protection over protocol. During the Infinity arc, she aids in awakening Sailor Saturn by resonating her Deep Aqua Mirror with the Holy Grail. She battles the Death Busters, confronting Mistress 9 and Pharaoh 90 while erecting protective barriers. In the Stars arc, she and Sailor Uranus feign allegiance to Sailor Galaxia for infiltration, leading to their temporary demise after a failed attempt to steal Galaxia's Star Seed. In her final moments, she affirms enduring hardship is bearable alongside Haruka. Both are later revived. Her personality blends grace with resoluteness. Though outwardly calm and introspective, she exhibits ruthlessness in battle. She cherishes art and beauty, channeling creativity into her duties. Despite loyalty to the mission, she harbors insecurities about her distance from the Moon Kingdom's legacy, finding resolve in protecting her new queen. Non-canonical media, like musicals, feature duets with Sailor Uranus reinforcing their partnership. Video games grant her unique attacks such as Sea Serpent Strangle. Alternate adaptations, such as the Cloverway English dub, alter her relationship with Haruka to "cousins," while the original material maintains their romance. Doll merchandise historically used the name "Nerissa" (meaning "sea nymph"), though official dubs settled on "Michiru" or "Michelle."