Mugen Senki Portriss

In a raving world, legendary knights stood up. Will they become gods of war or world saviors? Three Portriss Knights and sole human boy are now going to change the World!<br><br> Portriss Planet, home of where robots live in peace. However, this peacefulness was ruined by the sudden appearance of a Dictator "Dark Portriss". Dark Portriss plans to attain infinite powers through the use of the "Space-time destroying Cannon". The only ones able to stop this are the Portriss Knights! A boy, Yuuma, accidentally got into the Portriss World, and the Portrisses` adventure begins!<br><br> (Source: AniDB)