 Sadie was founded by Mao, Tsurugi, Aki, Mizuki and Sora in February 2005, and comes from the English word "sad", according to vocalist, Mao.Sora departed in January 2006 for "artistic differences", and in March, Kei joined the band to replace Sora.Their first live appearance was on March 18, 2005 at Osaka Big Cat, when they were the opening act for D, Fatima, Doremidan, shulla, Kra and others.