I recently watched a BBC documentary called "The Dark Charisma of Adolf Hitler," then read Shirer's The Rise and Fall of Adolf Hitler (Shirer wrote the Decline and Fall of the Third Reich and reported from Berlin during the 1930s). It seemed to me the concept of dark charisma could be generalization to many business and political leaders. Evaluating Hitler was a great place to start. As a failed painter and former corporal during World War I, Hitler did not exhibit much charisma, but attracted followers preaching hate especially toward Jews and communists.
Hitler stayed in the army and served as a spy to potentially subversive organizations, including the small German Workers' Party--which he joined and fashioned into the Nazi Party. Early on, as a new member he discovered his skill at organization and propaganda, and especially a charismatic orator. His speeches were angry, hate-filled and blamed Jews, communists and others for the defeat of Germany. He drew increasingly large audiences, enough to run candidates for the Reichstag (12 Nazi members were elected in 1928). It took the Great Depression beginning in 1929 for the growing dissatisfaction to bring Hitler's rise to power (the master-race and hate-mongering rhetoric were combined with strategic propaganda--ridiculous promises and lying were part of this skill-set). His party won enough seats for him to be selected Chancellor (amazing since he was not a German citizen until acquired by subterfuge) and then declared president. Other parties would soon be outlawed and he took over as fuhrer and chancellor. It's one thing for poor countries with no history of rule of law or democracy to be taken over by dictators. Germany was an advanced economy with political order and rule of law. In addition, plutocrats seemed all-powerful including business leaders, Prussian aristocrats and the army. Few of them seemed Nazi allies, but all apparently thought they could either control Hitler or use him for their own gains. He proved both persuasive and canny with one brilliant move after another.
Enemies were brutally eliminated, as were allies Hitler viewed as competitors. He rapidly grew the military, the economy improved and his popularity rose (it helps when opponents are rounded up and killed or sent to concentration camps). He conquered countries bloodlessly, by intimidation, lying, and other means of deceit, threats and bluffing--including Austria and Czechoslovakia. He quickly conquered Poland by agreeing to split Poland with his arch-enemy the Soviet Union (and also allowing them to take over the Baltic countries and Finland). He quickly defeated France and England by invading through the seemingly impassable Ardennes Forest. Then he attacked the Soviet Union and declared war on America. His brilliant successes were in part because his approach was entirely new and hard for "traditionalists" to comprehend and deal with--part of his dark charisma. After initial victories it was all downhill from there, often because he took total control of the military and proved totally inept.
Key characteristics of Hitler included selfishness, arrogance, lack of empathy, increasing regard for his own infallibility and therefore blaming others for any mistakes, and the complete disregard for human life (friends, allies and perceived enemies were all potential targets of his wrath which included imprisonment and murder). Hitler's belief in himself was unbounded: "I am convinced of the power of my intellect. No one has achieved what I have achieved. ... The fate of the Reich depends only on me. I shall annihilate everyone who is opposed to me." He expected to turn Slavs and Russians into slaves and kill all those not needed for the benefit of Germany. He expected his armies to die for him rather than surrender (defeat was intolerable) and at the end wanted Germany destroyed rather than give up. No expression of sympathy was given. He had periods of violent rage even when he was victorious. These increased as defeats mounted, for which others were always to blame (the Jews seemed to be a continuing target right to the end).