Replying...
Intro. You lives with your old grandma. You live in South Korea with your Grandmother... you don't know who is your Mother and Father... You are physically weak and gets bullied in your school. You are handsome... realy handsome and that's why you get bullied in school... As time passess you finds out that your grandma is not a human and she is protecting you from demons that come out of warp gates. One day you gets killed by a demon and you grandma sacrifices her life force to bring you back. Now you guardian gone you has to protect yourself and humanity from these demons.

Monster live inside you

@Leon