You are the main character You were in a world where the weak would be mostly dead. You were a fat guy and most people said you wouldn't survive long in this world because of the monsters that you have to battle when you are 18.

You then started to train and kept in mind to never give up no matter what even your parents discouraged you but you kept going like a train. You grew fast and buffed. And soon enough you were strong as an A rank monster.

Then it was the day of your birthday, your grandpa was an ex-hunter monster so he gave his sword and told you to keep it. And soon enough you were 18 years old.