An interesting conclusion to the series. It thought that while the overall conclusion was satisfying, the manner in which it was achieved was somewhat lacking. When Clary deceives Sebastion at the end, it never tricked the reader and made them predict what was going on, making the waiting time for the deception to reveal itself annoying. I did, however, I did like the Johnathan redemption scene that followed. I did also feel that half of the destruction and killing of off characters at the beginning to be a bit pointless, although I do feel that the set up for Lady Midnight was well done, even if you could tell what was happening.
Characterwise, I was glad to see the focus shift a bit onto some of the supporting characters, as we spend more time with Magnus and Luke as well as Maia. Having said that, all of these changes that we see with them, feel like they are setting up for something else. There were many times when I felt that this book was acting less as a conclusion to the Mortal Instruments and more as a prequel to the Dark Artifices.