Fun idea. It feels a lot like Sanderson's Mistborn with a dash of Sharpe and Sherlock thrown in, but it does succeed in being unique. The characters are good, and so is the plot so far. 
 My only problem is the major one of Fantasy, "some exceptionally talented youth has to defeat a god." Again. And again, I'll let it pass. Good book. I'm looking forward to the rest of the series.