Karl Dönitz

Karl Dönitz (1891–1980) was a German naval Commander who served in the Imperial German Navy during World War I, commanded the German submarine fleet during World War II, and eventually was given control of the entire German Navy (Kriegsmarine). 

In the final days of the war, Dönitz was named by Adolf Hitler as his successor, and after the Führer committed suicide, the admiral assumed the office of President (Reichspräsident) of Nazi Germany. He held this position for about 20 days, until the final surrender to the Allies. After the war, Dönitz was convicted of war crimes at the Nuremberg Trials and served ten years in prison.

Karl Dönitz in The War That Came Early
As commander of the German submarine fleet, Karl Dönitz found himself in an awkward position when Julius Lemp sank the American luxury liner SS Athenia in early 1939.

Dönitz was able to intercede on Lemp's behalf, protecting him from government officials who wanted Lemp's scalp. While he did chew Lemp out, Dönitz did not remove him from his command.