Based on

Movies like Space Sheriff Shaider: The Movie (1984)

An alien assassin, Omega, who makes a living by hunting down Space Sheriffs, arrives on Earth. Adapting a helmet, twin shoulder cannons, and other weapons into his fighting style after losing to Gavan and Sharivan, Omega is now targeting Shaider and challenges him to a fight to the death. Space Sheriff Shaider is the film adaptation of the Metal Heroes series of the same name. This movie takes place between episodes 19 & 20 of the TV show.