I was overall satisfied with the conclusion of the series. There is still primarily action, manipulation, and intrigue. While we find out more about the Darkling I felt that there were still some missing pieces. For someone his age, he seemed immature, and I feel that in this book the author took away some of that wisdom that was more prominent in other books and made him a flat villain. I guess I was expecting a bit deeper and realistic insight into his psyche, but was disappointed.
On the other hand, the theme of loneliness and belonging is very well woven throughout the series, it added on to the depth of the series.