Among these are references to the personality traits each of the four members of the group embody. Harold is a student of astrology, and through his character each of the group member's signs are revealed; Ivo is a fire sign, Afra earth, Harold air, and Beatryx water. At several points, Anthony mentions that only the four together, acting as a unit, can solve the problems presented to them. These traits are explored throughout the book, but especially during the closing sequences, where they form the basis of the game between Afra and Schön.