Avi, the author, uses darkness and dark colors to symbolize danger and evil. "A raw wind whipped the street lamps and made the gas flames hiss and flicker like snake tongues." Dupin is a man wearing a black army coat whose eyes are "deep, dark, and intense" just before Edmund runs into Dupin in the darkness of night. The lamp in front of the shelter is "glowing" and inviting to the homeless as a safe place from the wind and cold of the night. "The cold November moon--partially hidden by the mist--shed a pale light of a gravestone hue." Life is a sign of safety and life, while darkness is the uncertainty of life and the danger that is everywhere, according to Edmund's aunt.
The characters also serve as symbols. Dupin represents the side of Poe that is alert and sober, the man Poe could be if he stopped drinking. Throck is a symbol of greed because his real desire in helping Edmund is for the money, and for Edmund to sing his praises to Throck's superiors. Edmund's aunt represents the authority of adults over children, telling Edmund never to question adults and to accept what adults tell him because they know what is best for children. Edmund follows this advice at first, but then he realizes that adults don't always know what is best for him and his sister. He jumps into the bay to save his sister, symbolizing his break with the adult voices in his life who tell him what he can and can't do.