Acid Rain originated as a toy line from Toynami and is expanding as a media franchise. The Second World War ended in 1945 but it continues in a collateral world - the Acid Rain World. The endless battles have destroyed civilizations and polluted the environment. Resources have become scarce because of the unlimited pollution and warfare. Humans continue the war to seize resources for survival, and they control the mechanic armor and weapons to fight and defend themselves to struggle for tomorrow in the Acid Rain World.