Since I'm on a Glen Cook kick now I got the first Instrumentalities of the Night book. Oh boy. I don't really know what to do with this one.
Sort of like how the latter books of The Black Company adhere really strongly to Indian culture, IoN is pretty much 13th century Europe with all the proper nouns replaced with mad libs. The main character is definitely not a janissary in service to what is definitely not the Ottoman empire. Meanwhile the definitely not norwegians pursue some definitely not christian monks across the sea after their leader is murdered and then taken up by definitely not valkyries. He may have been murdered by definitely not Denmark, or by the Hidden Folk, which are what's actually interesting about the book.
It sort of reminds me of a more mature, much more dense version of the Golden Compass. You've got a world that very closely mimics the real one but with magic and shit. The Holy Land is holy because of the Wells of Irhian which pump out magic. The farther you get from the central concentration of wells (There are weaker ones elsewhere) the colder it gets until you reach endless darkness and ever-encroaching glaciers. The world is infested with the Instrumentalities of the Night, which are spirits sort of like the Unknown Shadows in Black Company. Everything from minor nuisances all the way up to the gods of the world are just bigger or smaller Night spirits. The aforementioned valkyries, the all-father who sent them, the gods of the definitely not Muslims and definitely not Christians, are all these spirits that are somehow connected to the wells.
Anyway, the main character's band of definitely not janissaries gets attacked by a bogon, a malignant demigod, and in a fit of inspiration he fills the experimental cannon they brought along with silver coins and blows the thing away. The rest of the book, when it wants to stick to what's actually interesting and not veer off into mind-numbing tangents about the history of the world (which you already know because it's identical to medieval europe), is about the upheaval that comes with that. The gods of the world are just bigger, smarter bogons. The genie's out of the bottle, man's discovered a weapon that can kill God as easily as it kills Bill from down the street.
That's why it reminds me of The Golden Compass. I can't decide if it's good or not. I think it would've been better if he'd focused on one or two subplots instead of burying you in history.