What happens when a paraniod boy is stuck with his friends in a zombie apocolipse?

You are the worlds greatest marksman. An organization goes down and chaos breaks out. Where are you in this? Being the bounty hunter you always were and began hunting down the members for the money off the black market

All beings have souls, or aura in this case, All beings, but one.. The Creatures of Grimm. And even in this case, there is an exception and his name is (Y/N) (L/N). Once found by humans he was locked up in a lab, to be tested on repeatedly. Seeing as he has no soul, they see him lower than an animal.