Mercenary Maruhan... the man who roams the darkness in the time of humanity's doom!

In the ancient era of the super-continent, where no border exists between the East and the West -- the race of Demonic Beasts begins an invasion against the human race, breaking the mutual non-aggression pact! And as humanity takes to the road to seek refuge, some gather to form the ultimate army for an attempt to kill King Rhode, the Chief of the Demonic Beasts... The intense story of one certain mercenary starts there!!