The Book Thief
Tone and Tonal Shift
Tone is the general attitude of a body of text. It could have a word that describes the general feeling of it.
Tonal Shift is when the tone of a passage can change from the original one.
Word choice can go into tone and tonal change, it sets a certain mood for the text and can change the mood at any point. Sensory details and other things can go into the text to change the mood as well.
Death sets a tone with the words he uses in the beginning. He states that he is not here to just be nice. He said that he was just doing his job. "Just don't ask me to be nice"