Night is a symbol in the book that doesn't just represent the physical darkness of night but also the darkness that Eli felt in his soul. He had said when looking in the mirror for the first time in a long time, " There only remained a shape that looked like a man. The dark flame had entered my soul and devoured it." All the evil and horrible things that surrounded him made heart feel dark. Every last night that Eli had in the camps, in the gettos, and at home with his family he has remembered and they have ment something to him.
Photo from: ciarafirefly.wordpress