Short answers, pulled from the story.
The English word Germans comes from the ancient ethnonym Germani, a term Roman writers used to describe peoples living east of the Rhine river. Julius Caesar first recorded this name in the 1st century BC while documenting his conquests in Gaul.
This linguistic shift began appearing in texts at least by the 8th century, marking the emergence of a distinct identity among speakers within the Holy Roman Empire. The modern German endonym Deutsche derives from the Old High German word diutisc, meaning ethnic or relating to the people.
Napoleon dissolved the Holy Roman Empire altogether in 1806, catalyzing a national awakening among Germans. This event followed centuries of political fragmentation where intellectuals like Johann Gottfried Herder had articulated identity rooted in language during the 18th century.
His regime murdered six million Jews during the Holocaust while waging military aggression that led to World War II. About 12 million Germans had to flee or were expelled from Eastern Europe following Germany's defeat.
About three quarters of the 100 million German speakers worldwide live in Germany where they account for 92 percent of the population. Modern Standard German is based on High German and Central German though notably not spoken by Volga Germans.