The central protagonist of the novel, a sixteen-year-old girl who has survived the alien apocalypse and is on a mission to rescue her five- year-old brother, Sammy. In the early pages of the novel, Cassia tells us that she has changed from the way she used to be?that she has become a killer. Given the context in which Cassia finds herself?kill or be killed?this increases our sympathy for Cassia rather than diminishing it. She is a teenage girl in unbelievable circumstances, and moreover she is an admirable teenage girl in these circumstances because of the way that she responds to things.
She endures and overcomes intense physical pain because she loves her brother and wants to get to him; she does not give into loneliness, depression, or hopelessness, although she deals with her situation with a kind of gallows humor that illustrates her intelligence and endears her to the reader. Like Cassia, Ben is a fairly average American teenager?endowed with a few particular gifts, like good looks and athleticism. After the invasion, however, Ben is transformed into a warrior. Ben differs from Cassia in that he has actually lost his entire family; thus, he is at first more vulnerable to Peloponnesus.
Since he is racked with guilt about his failure to save his younger sister, Ben is haunted and defeated. It seems he would actually welcome death, and understandably so; after all, what does he have left to live for? Ben’s feelings of guilt and depression make him especially susceptible to Pooch’s brainwashing tactics. Vouch plays on Ben’s desire for revenge?the last powerful emotion left to a young man who has lost everything else, it seems. In this sense, Vouch unwittingly saves Ben and turns him into a formidable enemy. As the old adage goes, “What doesn’t kill us makes us trotter,” and this proves true for both Cassia and Ben.
Ben’s coming-of-age happens during an alien apocalypse, rather than on a high school football field; ultimately, this renders him a much more powerful person than he would have been otherwise. On the whole, Ben is not quite as clever as Cassia or Ringer?who figures out that they have been brainwashed long before Ben does?but he is a genuinely kind and resourceful person, as evidenced by his determination to save Sammy.