The Question and Answer section for The Boy in the Striped Pajamas is a great resource to ask questions, find answers, and discuss the novel.
Greyed moves pins around because she is marking the locations of the armies of different countries.
Kotler had to at least pretend to have respect for Bruno's father because of Bruno's father's high rank. It is suggested that Kotler has an affair with his wife. Bruno's father ends up sending Kotler to the front lines of battle.
Kotler hated most people but especially Jews. Being a member of the Nazi party, Kotler was ecouraged to hate Jews. Kotler probably projected his own self-loathing on to weaker people like Pavel and Shmuel.