This book builds on the strong start of the first book by adding additional complexity in both plot and character. I really enjoyed how Sullivan did that very Harry Potter thing of taking seemingly throwaway comments from earlier in the book/books and bringing it to relevance in the future.
In particular I enjoyed the added depth given to the characters of Arista and Hadrian. I almost laughed out loud at Royce’s reaction to learning that Hadrian had secrets about his past aswell.
Plus without giving things away I thought the ending really added something to not just the book but the series as a whole