Demon kingdom re-emerged after being destroyed by a coalition of humans for 4 centuries there was somekind of peace (only humans killed humans) until a new demon king appeared and rapidly advanced. They were halted because of the great wall the chinese had built. Right after the destruction of the demon empire, sages foresaw demons returning and told the ruler of the time,Qin Shi Huang, to built a wall that would last centuries. Back to the present day, A thief named Feng somehow finds his way into the frontlines after being caputed by a general that was passing by.