This review was first posted on Music, Books and TeaI think it's fair to say that City of Lost Souls was easily one of my most anticipated reads for 2012. Whilst I wasn't really a huge fan of City of Fallen Angels (I loved it at the time, but the more I look back on it, the more I wished that the series stayed with three books). However, I feel that City of Lost Souls has definitely made the extension of this series worthwhile.The character development in City of Lost Souls was great, especially with Clary. I felt that she became more of a shadowhunter in both her thoughts and actions. She wasn't afraid to take risks (although most of them were extremely questionable), and I loved that she was able to stand up for herself to Sebastian, even when she knew that he would be able to easily beat her in a fight. Clary seriously kicked some demon ass in this book, and it was great to see her develop from an almost 'damsel in distress' to a serious shadowhunter. Her relationship with Sebastian really creeped me out, especially his actions toward her. I was cheering for Clary every time she attempted to kick his evil butt!I loved the dynamics in all the different relationships in City of Lost Souls, each relationship was different, and it was nice getting to have some Simon/Isabelle, Jordan/Maia and Luke/Jocelyn scenes, especially as there were very few similarities between the three relationships. There were also plenty of Jace and Clary scenes, even if Jace has gone slightly off the rails in this book. I loved how Clary kept reminding herself that the Jace she was with wasn't the real Jace, it would have been very easy for her to get carried away with Sebastian and Jace and forget what she was actually trying to do.The humour was one of my favourite things about this book, Simon had some absolutely brilliant one-liners! I really hope that he isn't the major character that gets killed off in the final book, as I don't think I'll be able to cope! Jace's snark was also present, even if he wasn't really himself, which made me love City of Lost Souls all the more.What is the significance of the praetor Lupus? I'm hoping there will be more explanation about this organisation in book six, although whether there will be, as we were given several scenes inside the headquarters in CoLS, remains to be scene. And I'm interested to see what role Maureen will be playing in the final book, I have a feeling that she's going to be an extremely key character in City of Heavenly Fire. It was also great to get to see the Iron Sisters, who forge the Shadowhunters' weapons. It helped to add a touch more depth to the back story of the Shadowhunters, which is something I really appreciated.City of Lost Souls was a really great read, and not the 'filler' book I was expecting it to be. This was a great addition to a series that I thought was going to go downhill with the extension that was added onto it. Finally - CASSIE, WHAT ARE YOU DOING TO MY OTP?! Seriously, the end of this book made me want to cry, purely because of this.