This book is quite a bit different from the original three entries in The Chronicles of Siala. In fact I don't really think it should be placed in that series at all.
I don't believe the book is set in Siala at all, it's most likely a completely different world created by another Dancer, maybe even Harold. The elves still exist as the Highborn of Sandor (who also use a completely different naming system than the rigid one of the first series. They also have a king and different houses, and no light and dark split), but there is no mention of gnomes, dwarves, goblins, orcs, ogres, etc. Not only that but the magic system is completely different, consisting of two types- Wizards who can bind demons and souls but do little else (they were also referred to as shamans, but very different from the shamans of Siala), and those of the gift, who are more traditional magic users.
It's hinted later in the book when Gray meets Harold that this is set a very long time after the events of the first trilogy, hundreds, or even thousands of years after. Harold has fully come into his own as a Dancer of the Shadows. He's very very old, and much like the Dancers of the first novels who played the Game as a ways of amusing themselves, he's now amusing himself by playing the Game of the world he's in. So in that he's become old and jaded, and well, much less human than he was in the original books. He's mastered his powers and become a true Dancer. His power is glimpsed by one of the Damned and viewed as limitless and said to be able to crush one of the Damned, the strongest beings in that world, like flies. But as a result, he's also succumbed to the boredom of being an ageless immortal being, hence why he's playing the Game. It's unknown if this world is of his creation or another Dancer's, though it's hinted that it's of his making ("It may be this world came out a bit flawed, but I know all about locks."). It's also unknown what kind of stake he has in this game. Is he one of the puppet masters controlling one side? Or is he merely a curious bystander? Harold has always reminded me of Vlad Taltos and now even moreso. It reminds me of when Vlad grew older and much more powerful and dangerous, a real player in his own right in the game of his world, and also had to leave his family and friends as a result. He also was unknowing of the power he possessed and quite powerless in the beginning, except for the rare instances in times of need where his burgeoning power displayed itself. This is very similar to Harold's growth as a character.
It's unfair to really compare this new series to its predecessor as they're very different. The first series was a more classical, Tolkien-esque journey, hugely broad in scope, to save the world whereas this is much darker and smaller in scope and more focused. Would I say I like this series better? No, but I've only read the first book and time will tell. The characters aren't as endearing as the first, Harold and Kli-Kli as well as Hallas and Deler really made the first series fantastic. It was also lighter in tone as well. But this has more action and less exploration.
Ultimately though, I really liked this book. The quality of the translation was excellent, though not nearly as good as the sublime job done on the first three books. My only annoyance is that there wasn't a series set in between these two series to see what became of Siala, the Nameless One, and the Master, as well as Harold's ascension to his full powers. But other than that, I'm glad to return to Pehov's world and works. Eagerly awaiting the release of the next few books.