I agree, especially when you see Don reading from different books with other characters' names on them- it makes it their coming-of-age story as well. Fiona may be the youngest character, but it seems everyone else will have grown by the end. Lia seems to be starting to forgive herself by seeing she can love someone, Mary's taking on her role way beyond a 'routine job' like she was at the beginning, Clandy's getting her mind back, Don's discovering his own power and Lucy seems to be learning how much self-sacrifice it takes to be a hero, how difficult it is to do so and how painful the consequences of the alternative are- not that she's a villain, but more to do with the burdens of guilt and fear she carried with her for two years, made worse when she couldn't bury them under a flickering hope and resolve after the hotel arc.
