The Hunter's Apprentice

Aerys is a young orphan who has been raised to become a monster hunter. However when a bloodthirsty demon escape, his apprenticeship starts sooner than planned. He becomes the apprentice of the strongest hunter alive, a living legend: Drake Dreadsteed who answers the call to track the monster down.

Hence start his journey as a monster hunter apprentice but he quickly finds out that it is nothing like what he thought it would be. Monsters roam freely across the known world and someone has to deal with them. That is a monster hunter's job.