The Promise of Blood
The Powder Mage Series - Book #1
by Brian McClellan
OK, so the book opens up with Field Marshal Tamas, the most badass general of all time, killing the entire royal cabal. The royal cabal are like real mages, who don't need gunpowder. The last of the cabal utter a warning of dangerous things to come. In the meantime, there's a private investigator named Adamat, who Tamas hires to investigate. Adamat's superpower, if you will, is that he has a photographic memory, and that makes him very, very useful for investigations. Finally, there's Taniel, Tamas' son, and he's a badass powdermage who can shoot two bullets at once. It's kinda nuts.
The world that McClellan creates is vivid and very real. Tamas is a good guy by virtue of being one of our protagonists, but not necessarily because of his inherent goodness. He's not... actually a good guy. But his goals are solid, and he's willing to do anything he can to achieve them, including murdering relatively innocent people.
As I was reading, I found myself holding my breath in parts, especially during battle scenes. I fell asleep and dreamed of investigating a crime where the only evidence was a bag of gunpowder. This book is that good.