Mirai Ninja: Keigumo Kinin Gaiden (未来忍者：慶雲機忍外伝, lit. "Future Ninja: Stealth Joy Cloud Device Side Story"), known as Cyber Ninja in the United States, Warlord in Canada and Robo Ninja in the UK, is a 1988 Japanese science fiction action film directed by Keita Amemiya, which was co-produced and released by Namco that premiered in October 1988 at the Tokyo International Fantastic Film Festival.

It is marked the first live-action film based on a video game, although it still unrecognized the distinction over Japanese films in video game adaptations to the United States as the reason it took over the record by the 1993 film Super Mario Bros. to critical and commercial failure.

It was released as a direct-to-video film on December 2. The film is based on the arcade game of the same name which was also developed and released by Namco.