Fumi Ootou, also known by the reading Fumi Oto, is a Japanese singer-songwriter and composer born on August 17, 1974. Her professional music career began in the early 1990s when she became a member of the popular idol group Tokyo Performance Doll (TPD), performing at major venues such as the Nippon Budokan and Yokohama Arena. After her time with TPD, she shifted her focus to songwriting and composition, leading to her solo debut in 1998 with the song "Kisetsu wo Dakishimete."

Ootou is directly connected to anime works through her performance of theme songs. Most notably, she performed the ending theme "Kaze no Mahou" for the television anime Popolocrois Monogatari, for which she also wrote the lyrics and music. For the same series, she performed the insert song "Watashi Bocchi" and handled its composition. Beyond anime, her vocal work extends to video game music; she sang the theme song "Kono Hiroi Nohara Ippai" for the PlayStation game Boku no Natsuyasumi.

As a composer and lyricist, Ootou has created songs for numerous other artists across anime, pop, and idol genres. She wrote the lyrics and music for Harina Funa's songs "Naite Iiyo" and "Negai no Kanau Basho," with the latter serving as the ending theme for the game Rockman DASH 2. Her composition credits include "SNOW BIRD" for Yukie Nakama and "Koko ja Nai Dokoka" for Nogizaka46. She also co-wrote the music for "Tsuki no Nagisa de Aimashou," an insert song for the TV anime Lime-iro Senkitan.

The musical identity of Fumi Ootou is rooted in piano singer-songwriter traditions. She frequently performs live shows characterized as piano ballad performances, often incorporating elements of mental health care and counseling into her events. A significant portion of her career is dedicated to choral music. In collaboration with lyricist Hiroshi Kurihara, she has composed several acclaimed suites for women's and men's chorus, including "Anata e no Uta." The piece "Sakura" from this suite has become a notable long-seller since its 2011 release and is widely performed by amateur choirs across Japan. She has also composed music for stage productions and musical theater.

Her industry significance lies in her versatility and longevity. Having started as a major-label idol, she successfully transitioned into a behind-the-scenes songwriter and a respected solo performer. Her ability to write for pop idols, anime theme songs, video games, and formal choral compositions demonstrates a broad musical range. She continues to perform regularly and release original music, maintaining a career that spans from the 1990s idol scene to contemporary composition and live performance.