Antagonist
Character Role Analysis
Death and Grief
You might think that the Eagle—who represents authority, moral rectitude, and righteousness—is the antagonist in this book. After all, he knows that he's the antithesis of adolescent shenanigans, and he's happy to play this role. But as the book progresses, we figure out that he's kind of a false antagonist—that he, too, is caught in the grips of the real antagonist of the story.
The real antagonist of the story is death, and by extension, grief. Although death is what causes Miles and his friends to grieve, it's the overwhelming nature of grief that does the most damage and almost crushes Miles's joy of life and his friendships. The fallout of death is the most difficult obstacle for all the characters to get past, but by coming to terms with Alaska's death and their roles in it, Miles and his co-conspirators are able to heal themselves.