There was no single leader during WW1. Each country had their own leader.
wwii- adolf hitler.
Joseph Stalin (aka Ioseb Besarionis dze Jughashvili) was the paramount leader of the USSR who held the position of: General Secretary of the Communist Party of the USSR Premier of the USSR Marshal of the Soviet Union (aka Generalissimo) during the Second World War.
Adolf Hitler the Fuhrer
Franz Josef
Roosevelt
The most powerful leader in Russia during World War I was Nicholas II. In addition, Nicholas Nikolaevich and Aleksei Brusilov were leaders during WW1.
Winston Churchill .
Emperor HiroHito
President truman
FDR
FDR
Franklin D. Roosevelt
Joseph Stalin was the leader of the Soviet Union during World War II.
Admiral Chester Nimitz (for most of the war)
Hideki Tojo was the leader of japan in world war 2.
There was no single leader during WW1. Each country had their own leader.