I think each book sort of finds its own theme as it goes on....

I think each book sort of finds its own theme as it goes on. 'Warded Man' was fear. 'Desert Spear' was exploration of the other. 'Daylight War' was relationships. Some of this is intentional, and some of it evolves naturally. The series as a whole is obviously something I have given a lot of thought to, but each book is its own animal as well.