While I have been honored with a review copy from the publisher, let me be very clear about something: I practically demanded it. :) 
 I read the rest of the series at the beginning of the month and grew so hooked on it that I couldn't pause to read anything else. And then, thanks to a friend, I pushed my luck and asked the publishers directly for a copy. I admit that I was practically foaming at the mouth, too, and nothing much changed when I received my copy. 
 So what is this? A raving from a fanboy? 
 Yup. 
 But let me be also very clear about something else: this book is amazing all on its own, or I should say, it caps the rest of the series like the Spear of Ala, as magical and grand a the city below the Earth, the bastion of magic that has withstood thousands of years of swarming demons, unaided. 
 Any issues I may have had with the previous novels are wiped clean away. Indeed, all of the characters, small and great, have their place in the upcoming battle that tears apart all the cities and hamlets, all of which withstand or fall under an endless onslaught of demons great and small. 
 The title also gives it away. Arlan and Jadir and Renna go deep into the bowels of the Earth to take on the Core and all the spawn and let me just say... it is amazing. So magical, so dangerous, so mind-blowingly huge. 
 This fantasy series is easily one of my favorites. Part grimdark, part extremely magical fantasy filled to the brim with demons, and part character study. Any kind of patience you give the previous books will be repaid with pure gold in this one, but be forewarned: there's some really graphic stuff here. There's another author who does a Eunich Army, of course, but George doesn't come anywhere as grim and descriptive as this. 
 Hell, I'm tempted to start it all up again and enjoy it afresh now that I've grown to love all the different peoples and cultures. 
 All I can and should say is Bravo! :) 
 I'm so very happy to have read this series. :)