What was the German monarchy, and how was it related to Prussia and Nazism?

Prussia was one of the three hundred principalities that
comprised what is now Germany. It and Austria were the two leading principalities. Otto
von Bismarck, later Chancellor of the united Germany, was largely responsible for
uniting Germany under Prussian leadership. He did this by a series of wars against
Austria and France, the end result of which was not only the cession of territory to
Germany but also a sharp increase in German nationalism. Part of Bismarck's plan was to
exclude Austria from the united Germany, as Austria would have been a rival to Prussia
for domination of the Empire. Following the Franco-Prussian War in which France was
humiliated, Bismarck arranged for King Wilhelm 1 of Prussia to be crowned
Kaiser (the German equivalent of Caesar) of Germany.There were only
two Kaisers of the German Empire, Wilhelm I and II. The family name ("House") was
Hohenzollern.

The success of the Franco-Prussian war left
Germans somewhat drunk with success and prone to a Social Darwinist way of thinking.
They considered themselves the fittest and best of the European species. They also
embraced a new authoritarian conservatism based on
nationalism.

Any connection with Hitler is indirect at
best. Hitler did appeal to German nationalism and socialism and promoted the idea of the
Germans as superior to all others. The German Empire under Wilhelm I and II had been, in
Hitler's vision, the Second Reich. (The First Reich had been the Holy Roman Empire which
comprised most of present day Germany.) Hitler built on this by calling his regime the
Third Reich.