Grezzo Co., Ltd. (Japanese: 株式会社グレッゾ, Hepburn: Kabushiki Gaisha Gurezzo, stylized as GREZZO) is a Japanese video game developer. It was founded in December 2006. Koichi Ishii, known for his work on the Mana series of games by Square Enix, was hired as CEO and president of the company in April 2007. The company's name comes from the Italian phrase "diamante grezzo", meaning "a diamond in the rough".