Although Mary Ann only appears in “Sweetheart of the Song Tra Bong,” she is one of the most memorable and unnerving characters in the book. As the only major female character, Mary Ann represents the sort of wholesome American girl many of the soldiers long for when she arrives in Vietnam to visit to her boyfriend, Mark. However, Mary Ann turns out to be a crack sharpshooter. She is drawn to and eventually joins the Green Berets, the elite team of soldiers staying nearby. She is last seen wearing a necklace made of human tongues and disappearing into the jungle. The implication is that the darkness and evil of the Vietnam War corrupted Mary Ann, and that the same darkness is inside every human soul, waiting to be brought out.