I was kind of surprised that two of the three protagonists from book one completely dropped off the face of the earth for this sequel. I was more surprised that after the first few chapters, I didn't really miss them. Telmaine was always my favorite anyway, and I cheered to see her coming into her own. I also enjoyed the further glimpses into her friends and family. I wish the breakneck pace of the book had slowed to allow for more development there.
I didn't find Lightborn culture quite as fascinating as Darkborn culture, but it was still interesting getting a closer look. I hadn't really thought through just how much more precarious their existence is, given the relative difficulty between artificially creating sunlight and darkness. It makes their embrace of magic understandable, though I was disappointed at how generic the magic ultimately was.