Mussolini was overthrown by the new government who sided with the allies. On April 29, 1945 he and 15 other fascist leaders were hung and executed.
Hitler had some 60 divisions in France in case of an Allied invasion of Europe, but when Sicily was invaded by the Allies and Mussolini was captured, Hitler, not wanted the Allies in Continental Europe, invaded Northern Italy and Simultaneously sent a rescue team for Mussolini, there he established a puppet government for Mussolini
Joseph Stalin may have respected Mussolini as a leader, but he hates Fascist policies and the fact that Mussolini had sided with Hitler against the Allies. As a Communist who believed in absolute state control, Stalin clashed with Mussolini on economics and the role of classes in society, so they were very far apart ideologically.
The fact that Fascist opposition against the invading Allies quickly crumbled and that Italy started suing for peace or at least an armistice. The Grand Council of the Fascist Party had by then already deposed Mussolini as its leader, and the King had fired him as Prime Minister. The Nazis did not break ties with Mussolini at that point. Surrender of Italy to the Allies would mean that Germany faced immediate invasion from the south. So the Nazis forcibly reinstated Mussolini and used him as a pretext to replace the crumbling Italian defence by a strong German army. Mussolini was kept in power by the Germans until the very end of WW 2. Only when the German troops finally retreated they left him to his fate. Mussolini was discovered when he tried to flee in a German convoy, was arrested and shot.
The invaded Africa because Benito Mussolini's fascists occupied those countries. Then they invaded Italy to remove Mussolini from power and take out Hitler's ally in Europe.
Mussolini
They were both lead by a Fascist dictator whose wheels were somewhat less than on the tracks. As they were the only Fascist countries in Europe it made sense that they should be allies, although it was certainly Hitler calling all the shots; in fact, as it became obvious that the tide of the war was turning against Hitler, the Italians actually switched sides. Oh, and both Hitler and Mussolini died at the end of the war.
Axis.
Germany (Hitler) and Italy (Mussolini)
he was captured by the Allies and hung upside down along with his Mistress in the town square.
That is a very interesting question. Please remember that Mussolini started the fascist movement in the early 20s. So this question has really never been poised or given much thought. If Italy had joined the Allies, then Hitler and his generals would have had to position troops in southern Germany/former Austria to cover them. During the Czechoslovakia situation Mussolini did move parts of his army to Germany's southern border, and the Czech PM was hoping that Mussolini might help to stare the Germans down. This is one of the many reasons that the Pact of Steel was formed. Hitler did not want to have to squabble with Mussolini. They were both dictatorships, so he did not fear the Italians going over to the Allies.
Nothing! Japan and Italy were allies.