LitCharts assigns a color and icon to each theme in The Book Thief, which you can use to track the themes throughout the work.
Death
Words and Language
Books
Stealing and Giving
Color, Beauty, and Ugliness
Summary
Analysis
Death describes himself a little; he doesn't carry a scythe, or wear a black robe unless its cold, and he looks like any person. 1942 is a very busy year for him, and he needs a vacation. There are so many humans to collect and colors to see. War is not Death's best friend, as the saying goes, but more like a demanding boss. When he remembers that year he likes to think of a little beauty as well, though, so he returns to the book thief's story.
Again Zusak expands the point of view to see the total impact of the war – Death is working overtime now. Death reminds the reader that he is telling this story to remind himself of the beauty and value in human life. Zusak has said that it was the saying "War and death are best friends" that inspired him to use Death as a narrator for the novel.