After the end of the First World War, a plan was proposed to create a Union to protect the people between the nations of Germany and Russia, Intermarium. In our timeline, this plan never even really began, but what if things were different?
After a few years of negotiations, the Federation of Intermarium was declared on June 15, 1921. A new capital was to be built for the new Federation as well--Intermarium City--located on the Polish/Slovakian/Romanian border. Four of the planned regions didn't end up joining--Finland, Yugoslavia, Ukraine, and Belarus (Finland and Yugoslavia for national reasons, and Belarus and Ukraine were swept up by the Red Army). Although Finland and Yugoslavia declined joining Intermarium, they became close allies and trade partners. Intermarium also had ties with Britian and France.
Being such a large nation, Intermarium was an economic and military power in Europe (even managing to hold together through the Great Depression), and as Germany, Italy, and the Soviet Union became more of a threat throughout the remainder of the 1930's, plans were made in case war broke out once again in Europe.
On September 5, 1940, German forces invaded Intermarium from the West while the Soviet Union invaded from the East. The plan sprung into action. Intermarium forces were sent to slow down the Soviets and Germans, Finnish forces moved into Soviet Territory, and French and British forces began a push into Germany. Italian forces attempted an invasion of Yugoslavia, meeting heavy resistance and Italian forces got bogged down fast.
In the Far East of Asia, Japan had begun an invasion of the Soviet Union through Siberia.
Germany--without the access to the Romanian oil fields like in our timeline--wasn't able to use the blitzkrieg to the extent it did in our timeline. Due to this, and Intermarium's greater size and population, Intermarium forces were able to hold off the German invasion. With most of the German's Army in the East, France and Britian were able to push into Western Germany. Italian forces were being pushed back and the Soviets had to deal with both Intermarium and Finnish forces.
On August 2, 1941, the Italian lines shattered, allowing Yugoslavian forces to push hard into Italy. Italy surrendered on September 1st.
Germany was next to fall as British and French forces captured Berlin on November 3 of the same year, even capturing high Nazi officials like Hitler. On the way to Berlin, they discovered the massive discrimination and hate crimes against the Jewish people and other groups committed by the Nazis.
With the war ended in the west, Intermarium turned their forces Eastward. By the spring of 1942, the Soviet lines were beginning to crumble. Then, on June 6, 1942, the Finnish broke the Soviet lines and were pushing deeper into Soviet territory. Intermarium broke their Soviet lines a week later. Finnish and Intermarium forces made it to Moscow on October 7, 1942, ending the war in both East Asia and Europe.
Intermarium gained the German territories of Prussia, Silesia, and East Prussia and the Soviet territories of Belarus and Ukraine. Yugoslavia gained a part of Italy. Finland gained Kaleria from the Soviets. Japan gained Siberia from the Soviets.
Germany was temporarily occupied by the French and British. The Soviet Union was forced to reform to the Eurasian Federation. Italy was forced to reform to the Italian Republic.
That's all for now, so please tell me in the comments section how you think this timeline will progress.