The leader of the Nazi regime during World War II was Adolf Hitler. He rose to power as the Chancellor of Germany in 1933 and later assumed the title of Führer, consolidating his control over the nation. Hitler's regime is infamous for its totalitarian rule, aggressive expansionism, and the implementation of genocidal policies, most notably the Holocaust, which led to the deaths of six million Jews and millions of others deemed undesirable. His aggressive foreign policies precipitated World War II, fundamentally altering the geopolitical landscape and leaving a lasting impact on global history.