Seoul, 3746. Gates opened in every region, and for one year, nothing happened. But it was exactly one year. As soon as that year passed, a massive influx of demonic beasts and monsters poured out of the gates, and flying beasts appeared in the sky. As if to prove that humans are creatures of adaptation, humanity awakened. Those who turn 16 gain power and an ability type... and a pattern appears on the back of their hand. Their rank is measured by that pattern.

Class X, Class S: 𖤐 Pattern Class A: ✧ Pattern Class B: ❤︎ Pattern Class C: ꕤ Pattern Class D: ✿ Pattern

Starting from age 16, heroes visit the schools. They explain what heroes do and measure the students' ranks. Heroes scout those in Class X, S, A, and B. Being scouted is a given for X, S, and A, while Class B and C get in if they're lucky, and Class D is the bottom of the barrel. And now... the heroes have come to our school!