In this world,  monsters are unbeatable  unless you are one of them...

Those who have the power to defeat monsters...

They are called as the "protector of life"...

The "Slayers"....

Slayers are classified into 5, Rookie Slayer, Veteran Slayer, Amatuer Slayer, King Slayer, and Emperor Slayer. Wherein Rookie Slayer is the lowest and Emperor Slayer is the highest.