After an unexpected incident, a new era had begun in the world. A virus, killing millions of people, has been brought upon the earth by an unfortunate event. The few who were infected and survived have gained special, inhuman powers.

Monsters and humans were always in a bloody feud. Countless conflicts occurred regularly, they engaged in battle not only with their enemies but also against their own people to gain even higher ranks. Until one day, an unexpected phenomenon transpired. The weakest dungeon, at the verge of destruction, performed a summoning ceremony, hoping that the summoned one would change this wicked world.