Falling into the Kill Line, I Changed My Job to a Monster Hunter

Sir, you ask what monsters we have in our country right now? Well, there are zombies wandering in the sewers; man-eating water monsters lurking in the sea; and those ancient demons hiding behind nightmares are still bewitching innocent people with their whispers... What's the scariest monster of all, you ask? Well, probably the group of vampires who rule this country. They wear human skin, wear suits and leather shoes, and live in large villas with gardens and swimming pools. They look exactly like ordinary humans on the outside, which is very confusing, but in fact they eat people without spitting out their bones, which is very dangerous. … Ethan traveled to Los Angeles, America, in a parallel world. Unexpectedly, sudden changes occurred, and many terrifying monsters and strange superpowers appeared here. In order to survive, he chose to become a monster hunter. This book is also known as "I am a Monster Hunter in America", "People in America, Survival Depends on Mutations", "American Catastrophe Era"