Fairy Tail's Demon Slayer

Before Zeref created demons, there were demons already born. since the dawn of time, these demons roam Earth land in secret and hidden themselves away. Until one Human. One man, discovered them, his name was Zeref, The Black Wizard. He wanted control over these demons. However, it proved to be a grave mistake for the black wizard. [[I DON'T OWN FAIRY TAIL]]