An ancient people built mystical fortresses made of melted stone; from the wall’s these fortresses defenders appeared to burn with a powerful energy and strike at their opponents with a supernatural force. Today most of these forts are abandoned and the art that made them lost.
There is a person who has a well-known reputation, probably involving something illegal. But this person is either very clever and crafty, or really like his or her privacy, for no one knows who this person actually is. As an added twist, perhaps this person is of an age that would noramlly be wildly inappropriate (say, a child is a much-feared bandit) or maybe not the expected gender or even race.