kukui is a Japanese band consisting of Haruka Shimotsuki (霜月はるか, vocal, lyrics & composition) and myu (composition, arrangement & lyrics) formed in 2004. Their name is taken from the kukui nut trees that grow in Hawaii. They have produced songs for animated TV shows and video games, most notably the Rozen Maiden series.
They were originally named refio+霜月はるか and released one single under this name (透明シェルター / Tômei shelter). They re-debuted as kukui in December 2004 at Comic Market 67 with a song titled ゆめわたりの夜 (Yumewatari no yoru). The following year they released 光の螺旋律, the ending theme for Rozen Maiden Träumend. Their first album, Leer Lied, was released in 2007. Their most recent work was released in March 2011, a song called 虚無の華 (Kyomu no hana).