AMAIM Warrior at the Borderline English Subbed

Summary:
Futuristic post-war Japan is divided into four military regions, each led by conflicting nations trying to gain complete control over the country. While the Boundary War—fought with the help of humanoid mecha weapons called AMAIM—has long been over, the rivalry between these factions is still ongoing, and, as a result, the Japanese are heavily oppressed.