The First World War was a global conflict between the major states in the world. The war, while fought most significantly in Eurasia, was also fought in North America. The two sides were the Expanse Powers (the Roman Republic, Comanche Empire, Greater Indian Raj, and Russian Tsardom), and the Allied Powers (the Egyptian Empire, Chinese Empire, Tribal Federation, Plains Confederacy, Persian Kingdom, and Norse Kingdom). The Empire of Japan sided with, but did not formally join, the Expanse Powers; similarly, the Kingdom of Ghana supported the Allied Powers. The only major nations who did not get involved were the Aztec Hegemony, and the Incan Empire.
The seeds of the war came from the Great Depression, where a steady increase in Roman unemployment led to the rise of the Roman Fascist Party, lead by Caius Albanus. During this period, Tsar Vladimir V died, and was succeeded by Ivan IX, who supported Roman Fascism. The two governments formed an alliance, called the Expanse Powers. The Greater Indian Maharajah and the Comanche Empire also joined into the Expanse, with the intention of gaining more territory.
Shortly after the formation of the alliance, the war began when Russian, Roman and Indian militaries jointly invaded China. The Chinese called for aid from their Egyptian and Norse allies, beginning the First World War.