I decided to only include a description of the first book because I don't want to give any spoilers for the series as a whole - and honestly it's pretty hard to describe the series as a whole without giving anything away. All you really need to know is that it's YA epic/high fantasy. And AMAZING.
The first half of The Demon King really, really dragged for me. It's a lot of backstory and history of the Seven Realms world. In some ways, I can overlook it because the second half of the book and each following book are fast-paced and intriguing. But I do wish the author could have spaced out more of the backstory and history portions to pick up the pace at the beginning. Other than that, I had no issues with the writing.
Luke read them as well and I feel like this is a good place to mention that he felt like the writing was lazy in places. He was annoyed at things like the use of the Gregorian/Christians/Western calendar in a world where mythology and ancient Rome (and thus many of the names of our months) did not exist. While I can see his point, I wasn't bothered by it, particularly given the fact that this is intended for a YA audience. But I think he made a good case, so I thought I'd include his thoughts in the review.
Like I said, the first half of book one is slow and then the series takes off and does not let up. I read all four books over the course of a few days because I could not put them down. There was crying and up way past my bedtime foolishness and shirking of my duties. It was an amazing series.
I highly recommend it, especially to fans of high fantasy. I think if you enjoyed Mistborn, The Kingkiller Chronicles, or any other YA fantasy, you'll be a big fan of the series. Also, for those who share my conservatism, don't be put off by the titles. I avoided reading these for a long time because I don't do demon/Satan books (yeah, I know, but I don't, so no use trying to convince me I'm wrong). Anyway, the title put me off from even learning about the book, but my friend Joyce persisted and I finally read enough about them to learn that they really aren't in any way about demons, so no worries there.