The Sage Dwight along with the Hero defeated the Demon Lord who plunged the world into darkness. However, they were falsely accused of becoming the next Demon Lords because of their power, and were thrown to the Death Valley to die… Although his flesh had rotten away, he lived on as a skeleton because of his grudge against the world. Dwight has vowed to turn against that broken world, and with a power that surpasses even the former Demon King, and also leading countless Skeletons he's going to start an all out war…!

The story begins when the gods call a conference to decide the whether to let humanity live or die, and settle on destroying humanity. But a lone valkyrie puts forward a suggestion to let the gods and humanity fight one last battle, as a last hope for humanity's continued survival. 13 gods will fight against 13 human champions in one-on-one battles to decide whether humanity lives or dies.

Since the Edo periods of Japan, gladiator arenas exist in certain areas. In these arenas, wealthy business owners and merchants hire gladiators to fight in unarmed combat where winner takes all. Tokita Ohma, nicknamed "Ashura", joins these arenas and devastates his opponents. His spectacular ability to crush his enemies catches the attention of the big business owners, including the Nogi Group chairman, Nogi Hideki.

Anezaki Satoru had a precious childhood friend, Ichinose Yuna, who was killed by a gang of rapists. Blinded by rage and thirst for revenge, Satoru gruesomely murdered 15 rapists and cut off their genitals, for which he was sentenced to capital punishment. After his death, Satoru regains consciousness in another world where all men have become mindless beasts. Finding himself lost in this world, he meets some of the struggling survivors fighting the hordes of beasts. What he learns is shocking... Yuna is apparently still alive in this world! Satoru chooses to join the fight in order to find his precious friend.

Suzuki Ryuto is an introverted, timid college student. Every day he puts on a fake smile, trying his best to blend into a group of outgoing students even despite cruel teasing over his virginity. One day he comes to a drinking party where he meets a beautiful girl, Kokoa. Per her request, he pretends to be her boyfriend to ward off the stalker who has been harassing the girl. Their tender love lead to great tragedy.

Since the eruption of Mount Fuji, the nights in Japan and this city have changed completely. Those covered in volcanic ash from Mount Fuji have become battle vampires, wielding tremendous power as they've started to kill each other and wash themselves in the blood of their fallen foes.