Karl Dönitz (* September 16th, 1891 in Grünau near Berlin) is a Konteradmiral (rear admiral) and since early 1936 „Führer der U-Boote“ (since 1939 „Befehlshaber der U-Boote“). He was the driving force building up the submarine arm in the German Kriegsmarine. Other Officers mock him as "Hitler Youth boy Quex" because of his fealty to the "Führer".
His fatherly friend and Mentor after the death of his father was Kapitänleutnant Wilfried von Loewenfeld, First Mate of the Breslau, it is said. In the First World War, thr Breslau (renamed Midilli) fought against units of the Imperial Russian navy in the Black Sea, as part of the navy of the Ottoman Empire.
Dönitz volunteered for the new arm of the submarines and became a member of its division of the Kaiserliche Marine on September 15th of 1916.
In 1936, German submarines lead by Dönitz participated in a secret mission in the Spanish Civil War.
In January 1939, he published his thoughts about nightly submarine attacks in the Booklet "Die U-Bootwaffe", which the Brits missed. His claims he could win the war with 300 submarines were ignored in Nazi Germany as well - when World War II broke out, the Germans just had 57 U-Boats. Still, those U-Boats had many successes sinking Allied ships, and Winston Churchill is seriously concerned that they might endanger the food supply of Great Britain.
His marriage in 1916 to Ingeborg Weber, daughter of the Prussian major General Erich Weber, meant an advancement in society for Dönitz. They have three Kids, Ursula (*1917) and the Sons Klaus (*1920) and Peter (*1922).
When being a British prisoner of war in the First World War, he learned Spanish.