- Birth Name: Kubota Keiko (窪田啓子)
- Stage Name: KEIKO
- Date of Birth: December 5, 1985
- Place of Birth: Tokyo, Japan
- Blood Type: B
- Bands / Groups:
In 2007, Kajiura Yuki started working on the soundtrack for Kara no Kyoukai novel's movie adaptation and founded Kalafina, to which Keiko belong, which was originally set to perform the ending theme songs for the seven movies. After the movies were finished, Kalafina continued to provide music for other animes like Kuroshitsuji and documentary shows like Rekishi Hiwa Historia.
In 2008, Kajiura Yuki also started performing live concerts and Keiko was a part of the singing unit along with Oda Kaori, Ootaki Wakana, and Kaida Yuriko; this brought up the idea for FictionJunction which featured the four vocalist and is a separate unit from FictionJunction YUUKA.
- [2020.05.27] Inochi no Hana / Be Yourself (命の花; Flower of Life)
- [2020.07.15] Ray / Hajimari wa (始まりは; The Beginning)
Compilations / Others
- [2005.09.22] Tsubasa Chronicle Future Soundscape II (#9 "Kaze no Machi e") (credited as FictionJunction KEIKO)
- [2008.12.24] Kajiura Yuki - YUKI KAJIURA LIVE 2008.07.31
- [2011.03.30] Kajiura Yuki - FICTION II (#2 "the image theme of Xenosaga II", #13 "heigen", #14 "maybe tomorrow") (credited as KEIKO)