The main characters so far in the story are Zedd, a powerful wizard, Chase, a fearless boundary warden, and Rachel, a somewhat brave child of Chase. What I have read has told me that they were chased down by a screeling, a deadly predator from the underworld. They all find a safe haven of some sort but the screeling knows the ways of the humans by now and how to hunt them down. Many in the hall where the three made it to were hurt, severely injured or even dead. In the text, its states that Rachel was a very mature child for her age in Zedd's eyes. In recent books, they explain how Chase was feared by many and Zedd was powerful and worshiped by many in D'Hara, the land after passing the boundary. I can not determine if all characters changed over time but Rachel has become a braver and much more mature than she was recently and Zedd became older and more fragile, yet still wise. Chase has not shown any significant throughout the story.
Evidence Pg. 10 "Zedd was impressed by her. He had never seen one so young use her head as well as she did.
Evidence Pg. 21 "'My lady, I'm an old man. I've never had any talent for sewing and my hands shake something awful. I'm afraid I would do more damage than I would repair, but if you insist, I will try my best...'"