In a far away land, where trees and grass grew wild and cities were built up around castles, the times were hard and dirty for most civilians. Everything was done by hand, nothing to help one along during a hard days of work, but after a hard day of work the city's tavern was the life during the night. Civilians enjoyed life this way, and lived safely.
Though, as time went on, people started to notice things in one another. It came to be known as witchcraft. Those that were speculated to be tampering in witchcraft, were burnt at the stakes, though, unknown to the civilians, it was a witch who gave them the idea to burn witches.
As people worried about witches, there was a group of civilians who decided to dedicate their lives to hunting down witches and learning everything they could about witches and knew how to hunt down witches. These people became know as Witch Hunters. Though, as these witch hunters became used to spotting the signs of witches, the real witches got scared and formed a blood ritual that would bring their protection.
Little did the witches know, their protection came in eggs. Mostly likely the witches decided to abandon their eggs, since it really wasn't the true protection they were hoping for. From these eggs, full adult dragons were born within the year to come. And these dragons being born alone, didn't know what their mission in life was. So, confusion created chaos when dragons enter the cities.
Witch hunters, also took on the job to hunting dragons, seeing there being witchcraft behind the reason these creatures were born. For those dragons that were attack, either died or suffered injuries that healed, and those that survived had magic of their own, besides flying and breathing fire, they could transform into a humanoid form.