This is a solid fantasy, with strong characterization and world-building, plenty of magic, dynastic intrigue and varied cultures. There is not so much as a soup̤on of M/M action, romance or even sex itself. To my surprise that did not end up being a problem since the slave story itself is the best part, and provides plenty of intensity that apparently can serve instead of sex--at least for this reader. I was especially impressed by Berg's female characters, since they are so often an abysmally weak point in M/M and fantasy. Lydia in particular is wonderful--strong, smart, honorable, intrepid.
Though I enjoyed the whole book, I was most caught up in the first half, which takes place in the court, and revolves around Seyonne's developing relationship with the prince. There the conflicts are very sharp and concrete, and the psychic developments complex but still readily grasped. I had more problems with the demon conflicts, especially the parts that went "off-world"--though it made sense in terms of the story and was well-plotted, this kind of dreamscape action almost always feels more washed-out and bloodless, even when the characters can actually die.
Bottom line: this is a good choice for fans of high fantasy, and fans of slave stories will also find plenty to satisfy their unholy lusts--so long as they can subsist without actual intercourse.