The empire of Nothgard, under Emperor Palethorn's rule, has began to invade the neighbors neutral countries, conquering them one by one, extending their dominion at the other side of Nothgard's border mountains, and during their invasions, their forces are being directed to the demon reamls, in an attempt to subdue the monster girls loyals to the Demon Lord. The war named 'The Great Invasion' has begun.