A woman met a suspicious death in the forest. Beside her, the sword-smith Amon discovers a newborn boy destined for tragedy and takes him in. Roughly 10 years later, this boy, named Gai and now Amon's apprentice, loses his right arm in an accident while forging a sword. Amon decides to take a sword called "Shiryuu," a weapon with demonic powers passed down through generations, and fashion it into an artificial arm for Gai. That was the beginning of it all... The story of this boy, who has become one with a demonic weapon and is drawn into a cruel fate requiring him to face countless battles, can be viewed as either the tale of "a beautiful weapon and an ugly person" or of "the cruelty of weapons and the beauty of humans." This is a completely new world of comic noir.