Keisuke Ilmari Ogihara (荻原イルマリ恵介, Ogihara Irumari Keisuke) is a Japanese hip hop recording artist and one of the founding members of the hip hop group Rip Slyme. He was born on June 17, 1975 in Helsinki, Finland to a Finnish mother and a Japanese father. He is best known by his stage name Ilmari (イルマリ), which is considered to be his middle name in Finland.