An anime adaptation of the novels, produced by Kitty Films, ran from 1988 to 1997. There is also a manga based on the novels, with art by Katsumi Michihara. In addition, there are several video game adaptations with the most recent release in 2008 being a real-time strategy game. The series did not receive an official English release until 2015 when North American anime and manga distributor Viz Media announced they had acquired the license to the novels. On the same day, North American anime licensor Sentai Filmworks announced their license to the anime and the anime was later released on Hidive starting on June 20, 2017.