This story takes place in the year 680 BC. In the beginning, all living beings on Earth lived in peace, until one day a massive crack appeared in the sky. This crack was caused because the gods could no longer protect humans from the evil forces.
From this crack emerged many monsters, which began to destroy everything in their path. They wiped out cities, villages, and anything they encountered. The humans begged the gods for help, but no answer came. The people went to the holiest church, where they had once sworn their loyalty to God and received blessings from the gods. But this time, the gods did not appear. Soon, the monsters quickly took over the world and began enslaving humans.
The monsters were divided into different ranks. Twelve years later, in the year 692, a god entered the holiest church. He broke a divine rule that stated no one was allowed to descend to Earth because he was internally broken, seeing this beautiful world descend into ruin. The monsters quickly sensed the divine energy and rushed towards him. However, the god had not come to fight but to awaken a special power that was hidden within the humans' bodies. To do this, he had to sacrifice himself.
Thus, the humans were like reborn, and although everything remained the same, they now possessed abilities and knew how to use them. With their newfound powers, the humans began fighting against the evil, and the first war between humans and monsters broke out. Every time the humans defeated a monster, they grew stronger and gained more knowledge. Since the humans were in the majority, they won the first war. The demons retreated to a large island to gather their strength and plan another attack on the humans.
The main character's name is Rengouji. For an unknown reason, he finds himself on a dangerous monster island, where he fights daily for survival. One day, however, a ship arrives at the monster island, and Rengouji gets the chance to leave the island. He is dropped off at a small village, where he makes a decision: he wants to grow stronger in order to one day find out why humans lost contact with the gods.
On his journey, Rengouji gathers clues and eventually uncovers the entire truth. Only one task remains for him: to find the cause of the rift between humans and the gods. This cause is the evil god of the underworld, whom he must defeat in order to restore the connection between humans and the gods.