The Dragon's Mage

Once upon a time, there was a dragon...
Take one newly trained Fire Mage. Make him the first (sane) Fire Mage that's been born in the past two hundred years. Have him leave home and venture into the Empire of Sol.
Add one powerful, curious, fire-eating dragon. 
Fire Mage Haikrysen never imagined that he would be adopted out of the blue by a dragon. But then, he never thought he'd find a permanent home in the northern section of Sol, working as a firefighter either. Still, he likes his new home and adores his dragon companion—even if she does hoard jewelry and eats whole sheep for breakfast. 
But his peaceful days end abruptly when an arsonist starts torching the eastern section of the empire, his attacks becoming progressively bigger and faster. It's beginning to look like he's another insane Fire Mage on the loose. 
Krys, Kaya, and his partner Mari are sent to investigate, but they have no idea what the aim of the arsonist is, and very little knowledge of the man. Desperate, the three of them race against time to catch the madman before he burns a path across the whole empire, and everyone in it. 
Dragon's Mage by Honor Raconteur, set in the Advent Mage world, features the returning character of Haikrysen, the first real Fire Mage of his generation.