Mai (舞), real name Mai Kudo (工藤 舞, Kudō Mai; born July 18, 1984) is a J-Pop singer from Hokkaidō, Japan. She is a talent of the Fit One management company and part of the artists' roster of Rhythm Zone owned by Avex Entertainment Inc. She originally debuted as "Ruppina". As Ruppina, she recorded the song "Free Will" which was used as the 9th ending theme of the Japanese anime series One Piece.
Source: “Mai (singer)”, English Wikipedia (CC BY-SA 4.0), excerpt