One perspective is that the aliens have a deadly adaptable virus that would kill human kind if ever unleashed, in contrast the aliens feel that the humans are killing them for no reason. In reality the war is a misunderstanding that two characters race to remedy before the fleet arrives in Lusitania. Card masterfully uses different perspectives to give depth and suspense to the story.
A final craft move Card uses is foreshadowing to build suspense. He does this in a number of situations, he foreshadows how Jane came to exist and how the descolada virus works, among other things. This quote, "Maybe it's a kind of language," is an example of this use of foreshadowing, it foreshadows that the genetic molecules the descolada people are sending may be a type of language. Card often uses foreshadowing to convey themes or important information.
Overall, Card uses a net of craft moves to ensnare the reader in his complex plot. These craft moves also lead to prove the theme of sacrifice, and how it is more important to save what you love than yourself. Card analyzes that intelligent life is equal to intelligent life even if intelligent life is