I loved this series. It was a really good conclusion to the series. There were a lot of things that I liked about this book. It kind of gave you a peek into her next series TDA. I really liked Emma and Julian was amazing. Some authors feel the need, because it is the last book, they have to kill off half of the good characters. She did not do that in the book. There was a war and some did die, but it was not too much. Most of the loose ends were all tied up. And it meshed TID, TMI, and TDA together. It was not spoilery for either of the other series, but if you read TID and have been following the updates for TDA it makes sense. My main complaint with the series was that Clare has a bit of a habit of Special Snowflake Syndrome. In the second installment, I didn't notice as much of it. It gets brought back at the end of this series.
I get that the Clary is the main character of the series, but I felt that Jace should have been the one to kill Sebastian. It was her brother, but I felt that him and Jace were opposites. Both were raised by Valentine, had the same training, and Sebastian was always jealous of Jace. Clary all of a sudden remembered this rune she came up with several books back and it saves the day annoyed me but that was my only big complaint. The book was from different people's POV. I liked this and I didn't. It got confusing and slightly irritating at times. It was a good conclusion to a good series.