On July 28th, Austro-Hungarian forces began a general invasion of Serbia. Having extensively planned for this operation previously, with most officers having been taught Simple Danubian, and with a great stockpile of prepared supplies, it was a decisive victory. By the end of September, the country had been fully occupied, and only irregulars continued the fight for Serbia. Austro-Hungarian armies linked up with those of Bulgaria and the Ottomans, beginning a joint invasion of Greece, to dislodge Entente ships in the region and threaten Egypt. The Romanians, which had entered the war on the get-go, proved far more resistance with Russian reinforcements, but were eventually pushed back. By November of 1915, the Balkans were firmly in control of the Central Powers.
Somewhat further to the north, the Italians managed to push the French in the extremely bloody Battle of the Alps, though its colonial holdings were lost. Furthermore, on the border between the Ottoman levant and the British colony of Egypt, combat began to unfold.