The Subtle Knife

In this book we were introduced a new character, Will that very different from Lyra. He was forced to grow up faster that other kids because of his situation. Where Lyra was mischievous and impulsive at times, Will was levelheaded and calm. And Lyra saw Iorik Byrnison within Will that made her trust him wholeheartedly.
I was very surprised how attached I was to Will's character. 

Human vs Authority. Kinda mind blowing.