It is set in an alternative universe where magic works, allowing conjurers to enter 2 additional planes, the hidden world and the land of the dead, and to summon demons, among other things. The world seems stuck around World War I; the British Isles are gone due to earthquakes; America is unexplored beyond the Hudson; and the dominant world center for development & technology is Abyssinia (nice!).
The dozen or so major characters are mostly well developed - there is some inexplicable behavior, but not too much. One of the major characters is a young woman, a mostly male soldier, and a dog. Nice!
But the plotting seems odd. At times major events happen, but you're not quite sure they did. A somewhat interesting universe, but the story is really not that engrossing, and very slow at times. The 2nd 1/2 of the 1st book is spent by some of the characters trying to travel 40 miles west to Albany. They barely get started, and never come vaguely close to Albany.
It's interesting how much a part feudalism plays in so much fantasy. The long lost princess, etc., etc. The Germans, who are mostly the bad guys for the 1st half of the series or so, are pushing rationality and maybe even The Enlightenment. The princess' noble family, of course, believes in republican ideals.
But you see this in sci fi too. The Atreides in "Dune" were lovable fascists, but they were fascists none the less, just like the unlovable fascist Harkonnens.
I think some sci fi before I'm back to economics.