Ten years ago, a red moon inexplicably appeared in the sky. It created a wormhole connecting Earth to another world, and countless creatures from that world poured onto Earth. Meanwhile, spiritual qi leaking from the other world gave rise to "Hunters" on Earth.
Hunter levels range from 1 to 100.
Levels 1–20: Beginner Hunters
Levels 21–40: Intermediate Hunters
Levels 41–60: Advanced Hunters
Levels 61–80: Title-Class Hunters
Levels 81–100: Hall-Class Hunters
With the Hunters' help, countries around the world successfully faced attacks from creatures of the other world. They also discovered "dungeons" from that world appearing on Earth. Each dungeon contained vast quantities of otherworldly crystals. Thanks to these crystals, human technology developed rapidly, and Hunters became the most respected profession in society.
