Originally founded in the early 90s as Studio Zeal, which Oono Tsutomu freelanced under until it was formally established as Zeal Co. Ltd., on March 5th, 2003. It was an animation, illustration, character design, game art, and game development company. Zeal worked on many anime and games (largely eroge).

The staff were Oono Tsutomu, Ichikawa Saasha (as Motosugi Tomoe), Mai-Take (舞茸), and Aki (あき) who joined when Mai-Take left.

See Zeal Co., Ltd..