Hunter Without mana

The Gates Appear out of nowhere, Monsters Flood into the earth, Humanity modern weapons isn't good enough to fight against the monsters, The Humanity fell down to despair.
But in the time that humas surrendered against the ferocious monsters, People Who awakened special power appears. They Fight Back against the Monster the humanity won after the war.
Fast forward after 50 years
Hunter becomes a big profitable industry
Citizen knows that they need the hunter and every single young people dreaming to be a hunter and become rich and famous ,
This is the story of Gab the Hunter who don't have 0 mana.
the forever E class hunter.