** spoiler alert **
Flanagan's to be commended for keeping this series going so strongly. The characters continue to develop as they mature, and he keeps on bringing new societies in for the adventures to explore. perhaps those cultures are a little transparently modeled and simplistically presented, but that's not necessarily an entirely bad thing in an action plot.
I do wish, however, there were a little bit more remorse shown for all of the deaths. Once combat scenes begin, it's all action and all about the head counts--the heroes never respond to the deaths they cause like little machines and as a group there is not enough acknowledgment of what the head count represents: lives ended, however admirable the cause. In other words, it's time for the protagonists to develop a little bit more mature conscience. So many young boys, particularly, picked up on this series as a sort of adventuresome role model...and in the end, it's an overly simplistic model. Please, Flanagan, use your powers for good.