A short manga adaptation of the UFO Robo Grendizer anime. Released alongside the anime series, UFO Robot Grendizer follows the adventures of Duke Fleed, the Prince of Planet Fleed. Disguised as Daisuke, a farm worker, he fights against the forces that destroyed his planet, the Vegan Empire, who also created Grendizer, which Duke stole to battle them. Although not originally considered part of the Mazinger series, Koji Kabuto and the Mazinger mechas appear in this series, making it somewhat of a sequel. Grendizer introduced the concepts of a transformable robot and a space mecha, which were later adopted by other mecha series. It was extremely popular in Japan, Canada, France, Italy, and the Arab World, and maintains a strong following in those countries to this day.