Napoleon was a Corsican who had once tried to write a novel. Corsica had been conquered by France the year before he was born from Florence. After being sent to a military school in France and being shunned there, he returned to his homeland to fight for it's independence he was shunned there as well. He then returned to France at the height of the revolution in the military and, also through cunning and luck rose to become First Consul of the Republic and then it's emperor.
There is a third despot who was also an ethnic outsider who rose through the ranks to become a despot in the Soviet Union. Josef Stalin (born Josef Dzugashvili) was an ethnic Georgian who was a bank robber and had once studied in the seminary. He became part of the communist party and rose through the ranks to become the leader after Lenin's death also through cunning and luck.
There are differences between the three men of course. Hitler and Stalin were genocidal ideologues but Napoleon was only interested in personal glory. Napoleon and Stalin could be thought of as enlightened despots (though far more despotic than enlightened) who modernized their countries in the same way as Frederick, Catherine and Peter the Great by improving literacy and education (though Stalin did it far more brutally). Hitler, on the other hand, improved the economy, but did little to improve on Germany's past intellectual achievements by expelling scientists like Einstein and banning books.
Hitler and Napoleon of course were insatiable conquerors of Europe and North Africa who were both done in by invasions of Russia. Hitler and Stalin were allies at first in WWII. They carved up Poland and Stalin attacked Finland at the outset of the war. Stalin wisely switched sides when Germany invaded the USSR in 1941.
Stalin expanded territory some but he knew his limits. He already had the world's largest multinational empire and preferred to expand his sphere of influence by supporting insurrections and coercing neighboring nations like China, Korea, and eastern Europe. In the end this may have made his influence far more long lasting and sinister than either of the other two.
Stalin's rule was followed by a period of seeming stability but his empire eventually did break up almost 50 years after he died. Napoleon's rule was followed by a restoration of the Bourbon monarchy which was followed by periods of revolution. This led to his nephew becoming Emperor Napoleon III in 1848 until 1872 when France finally became a republic after Germany deposed him. Hitler's rule was followed by a partitioning of Germany and the rest of Europe into the prosperous and free west and the dictatorial east and the . This partitioning ended in 1989 when Stalin's regime ended in 1989-1991.