Mezue ahịrịokwu na-esonụ: Bọlgeria, bụ́ nke nwere ndị agha nọ n'ala ndị dị na Balkan, busoro Serbia agha n'October 1915. Britain, France na Italy zara site n'ịkpọsara Bulgaria agha. Na mmekorita ya na Germany, Austria-Hungary na Ottomans, Bulgaria meriri agha megide Serbia na Romania, na-eweghara ọtụtụ Macedonia (na-ewere Skopje na Ọktọba), na-aga n'ihu na Gris Macedonia, ma na-ewere Dobruja site na Romania na Septemba 1916. N'ụzọ dị otú a, a chụpụrụ Serbia n'agha ahụ ruo nwa oge, a napụtakwara Turkey ruo nwa oge ka ọ ghara ịda. Ka ọ na-erule afọ 1917, Bulgaria wepụtara ihe karịrị otu ụzọ n'ụzọ anọ nke nde mmadụ 4.5 ya n'ime ndị agha dị ike nke 1,200,000, ma kpatara nnukwu mfu na Serbia (Kaymakchalan), Great Britain (Doiran), France (Monastir), Alaeze Ukwu Russia (Dobrich) na Alaeze Romania (
Tutrakan).