What are the motifs in Digital Fortress by Dan Brown?

Revenge is a recurring idea in the story. Ensei Tankado's mother was a victim of radiation after the bombing of Hiroshima. She died of complications shortly after his birth. Tankado was born deformed because of the radiation and his father, unable to accept his son's imperfection, abandoned him. For much of his childhood, Tankado had sworn revenge on the country that destroyed his family and left him deformed.