The book begins with a fascinating exorcism scene straight out of a horror movie as a priest of the Argolian Order manages to drive a demon out of a young farm girl. The world is filled with supernatural evils which said order fights using a combination of faith and their not-quite-heretical knowledge of magic. Legendary exorcist and witch hunter Horskram soon finds himself on the trail of a much-much more dangerous threat and is aided by his apprentice Adelko. The adventures of the two are disrupted by the Jarl of Thule raising an army to rebel against the king who spared his life when his father did the same.
I'm actually skipping over a large number of the subplots since this is one of the books which follows a George R.R. Martin pattern of many different viewpoints on the events around them. Damien Black's universe is somewhat more mainstream than Martin's own with clear divisions between good and evil as well as a focus on the failures of the knights to live up to their ideals as heroes. At least in this world.
Overall, I very much enjoyed the two central plots of Horskram trying to find the missing book of sorcery that his order has protected for centuries. I appreciated the Sherlock Holmes and Watson kind of relationship he had with Adelko, which also reminded me a bit of the protagonists in THE NAME OF THE ROSE. Adelko is probably not fit to be a monk but probably not going to find the life of a warrior to be the romantic one he thought of either.
Damien Black has excellent world building and while I think he could have done a slightly more thorough job of hiding his influences of differentiating the main religion from Medieval Catholicism, the world makes sense and invokes numerous real life historical as well as religious sources. He incorporates demonology, the Fair Folk, Norse myth, and Greek without missing a beat.
I think my favorite characters were the few morally ambiguous in the setting. Characters who can't control their homicidal fury at being looked down upon and snooty murderous nobles who are, nevertheless, on the side of the heroes. Seeing them contrast against the heroic Horskram was some of the best portions of the book. I had a similar affection for the King's widowed sister who simply wanted a relationship with her knightly lover but found him treating her terribly in the name of honor as well as duty.
If I had any complaints about the book then I think at 600 pages, the book is a bit overlong and they could have tightened the book considerably. I never quite bonded with the character of Adhelina and felt her character arc didn't intersect with the main plot enough to warrant presence in this book. I would have moved her to the sequel where she will, presumably, play a bigger role in the story.
In conclusion, this was an enjoyable novel that I found quite entertaining. It is not quite as dark as it could be and could be a bit tighter but it's, overall, quite a good work. I think fans looking for a solid work of epic fantasy then they'll probably enjoy this.