This was another fun read from one of my favorite authors. New characters, new story-line... but this book is a lot less coy about being a part of the Sovereign-verse than some of the other books. We even get a straight-up meeting between the MC, and the MC of another series... albeit that second MC is a child here. That clearly sets the timeline of this book 30-or-so years in the past of the other series. We also get a few more hints around the edges, about how the Sovereign-verse is put together, and the over-arching mechanics... but also a few more puzzles to ponder.
At the same time, if you're not following the greater Sovereign-verse, this books stands alone perfectly well: you don't have to have to have ready any of the other books at all (I promise), to enjoy this book by itself.
The MC isn't any sort of protagonist here, at least not at the start. Not a BAD guy, exactly, but certainly not a hero. And he's still nothing approaching a hero at the end, either... but he's certainly changing. And he's still not sure if that's a good thing. But there is real evil in the MC's universe, and we all know our MC will end up on the right side of that eventual confrontation... right? :-)