The infamous dictator known for the atrocities committed during the Holocaust was Adolf Hitler, the leader of Nazi Germany. His regime systematically exterminated six million Jews, along with millions of others, including homosexuals, disabled individuals, and political dissenters. This deliberate genocide aimed to promote Aryan supremacy and involved the establishment of concentration camps. Hitler's actions not only changed the course of European history but also left a devastating moral and cultural impact that is still felt today.