Deimos

On ancient Mars , two races, the Deimosians and the Phobosians , built a highly advanced scientific civilization . However, the two races repeatedly waged war over who was superior. Eventually, a nuclear war broke out, and Mars became a dead planet. Some Deimosians and Phobosians managed to escape and emigrated to Earth . Eventually, the Phobosians repeatedly attempted to take over Earth, believing that "we, the most superior race, deserve to rule the Earth," but their plans were thwarted by the Deimosians. Thousands of years later, we are now in the present day. The mountain village where the Deimosians were hiding was ambushed by the Phobosians, and all of the Deimosians were massacred except for the protagonist, a young boy named Shinsuke. Shinsuke, the only survivor, discovered and revived the giant robot "Deimos," which was the Deimosians' guardian deity , and began a counterattack against the Phobosians.