Italian irredentism was a major factor in the success of Mussolini's popularity as leader. And one of Italy's most disputed areas was the Dalmatian Coast in the Balkan region. While Italy was given the city of Zara, the rest of the region was given the newly-formed Yugoslavia. The fact that Italy was denied this accession of territory was essential for the rise of Benito Mussolini. Il Duce's ego was enormous, believing himself to be someone fit to create a new Roman Empire. But the Italian army was pitiful, especially in comparison to the other Great Powers. They were ill-equipped, was lacking in military talent and only Mussolini was confident that Italian troops would be exceptional. But even he expressed to Hitler that Italy wouldn't be ready for war until 1942. Nevertheless, Italy entered World War II on the side of Germany in 1940. The Italian Army only had entered conflict with Libyan rebels, Ethiopia, and Albania. The reason why those were such easy victories was the Italian superiority over their targets, but it wasn't a grand accomplishment. They sent in volunteers in the Spanish Civil War to aid Franco's army, but they were woefully outperformed by the power of the German divisions sent in the same conflict. And while Germany enjoyed successful victories throughout 1939-40, Mussolini was determined to have a campaign of his own. But he was fatally overconfident in his choice: Greece. The Italian invasion of Greece is considered to be one of the worst mistakes made in World War II. Only did the Greek armies benefit from their geography, but they were better-equipped and more organized than the Italians. Worse yet, the Greek prime minister even modeled his government on Mussolini's reign in Italy. With this invasion, the Italians opened another front for the Allies to fight in and in odds that were heavily against Mussolini. Eventually, Germany had to send divisions to Greece, where again, they easily outperformed the Italians. Hitler had originally planned to invade the Soviet Union on May 15th, 1941 but British firepower in Greece forced him to delay Barbarossa by 6 weeks. And we know how the Germans suffered through the Russian winter. In short, not only the Greek campaign costly and detrimental, but it was meaningless.
But what if Mussolini had directed his aims on Yugoslavia instead? The newly-formed country had the disputed land that Italians vehemently claimed as their own, particularly the Dalmatian coast. Not only that, but the Yugoslavian Army was even worse than the Italian Army, suffering from the same poor equipment but also plagued with ethnic tensions. Yugoslavia did not have the same geographical advantage as Greece and it was not ready for conflict. The Slavic nation was also against the idea of their government siding with the Nazis. What if Mussolini is convinced by his generals to attack Yugoslavia instead? What if Hitler found out about plans to invade Greece and pressure the Italians from conducting it? What overall effect would this have in the war? Would the Germans benefit from an earlier date of Barbarossa than OTL? Would the Italians succeed against the Yugoslavian army, or will it again require German aid? Will Greece remain neutral and prevent either faction from having military access or will it side with the Italians later on? Will the Axis Powers have a greater advantage in WW2 and possibly win, or will the Allies still gain the upper hand and defeat Germany and Italy?