Based on the Zanmataisei Demonbane adult visual novel game by Nitroplus. The story takes place in the world where both science and magic have advanced, and Arkham City is the metropolis that has prospered due to this highly advanced magic. However it is threatened by a criminal syndicate called the Black Lodge. Master Telion - the most powerful wizard, scrupulous criminal and sociopath - is the leader of the Black Lodge, and will stop at nothing to complete his secret agenda. To counter the rampaging of Arkham City the Hado Family Group, the guardians of the city, build a powerful robot named Demonbane, to stop the Black Lodge's nefarious plans. And so the battle between Demonbane and Master Telion's Black Lodge - for Arkham City and the world - begins.