The Remnant Files are just something for my Ace Combat-RWBY crossover: Skies of Remnant, to go over the conflicts that preceded the show.

RWBY and Ace Combat is the property of RoosterTeeth Productions and Bandai Namco respectively.

The Great Remnant War:

For as long as Humanity and the Faunus have existed, there has been conflict and the Great Remnant War was no exception. A number of factors can be attributed to the beginning of this massive and destructive conflict. Over the course of 11 years, the two alliances on Remnant, the Grand Pact of Freedom and the Unified Powers fought each other for control of Remnant and over 16 million were killed in the first five years of the war. By the end of the war in 2245 at least 95.7 million fatalities were confirmed, the largest loss of life in a single conflict among nations. Things like nationalism, imperialism, oppression, alliances, greed, ignorance of their neighbors, and the very idea of individualism were causes of the war.

Causes:

One such factor that lead to the Great War is imperialism in a number of nations as they sought to have its own large empire. The most well-known empires at the time were the Britannian Empire, the Empire of Ugellas, the Dominion of Emmeria, the Recto-Gebetian Empire, the Imperial Republic of Belka, and the Erusean Empire. Many nations attempted to make their own empires, but failed repeatedly to defend them from the creatures of Grimm and keep their colonial holdings in check. Meanwhile, the nations of Verusa and Emmeria expanded their territory in an attempt to restore national pride and recover from previous conflicts decades earlier.

Fear of communism was also a major factor to the war, as the Yuktobanian Revolution and the formation of the Union of Yuktobanian Socialist Republics troubled many across Remnant, particularly Emmerian monarchists and Verusan republicans. Both governments feared similar uprisings in their respective working classes. Verusa, having disposed of the previous hapless pro-West imperial government decades ago in a rebellion, wished to regain control of the western Pacific Ocean and its resource rich lands in order to restore national pride and aid its industrialization. The military buildup by Verusa began with acquisition of the Ugellan warship designs in the 1920s, strengthening its military industrial economy alongside Emmeria who spent this time expanding its colonial holdings in the Africia peninsula, Europa and Sotoa in particular, building up its Dust reserves with Africian Dust.

Nationalism was another major factor of the war, as members of each major (plus some minor ones) nation's legislatures, militaries and the populace thought they were better than their rivals. Democratic countries such as Vale, Mistral and Osea thought themselves as being the paragons of democracy, freedom, and equality. The UYSR thought that it was the liberator of workers from the supposed tyrannical grip of capitalism. Meanwhile, more…imperialistic and militaristic nations like Mantle, Ugellas, Emmeria, Belka, Verusa, Vacuo, and Erusea believed that they were defenders of humanity, at a certain cost of course.

A number of unresolved territorial disputes would also serve as a factor. A notable example of this is the aftermath of Aurelian-Belkan War of 2171, which left a portion of its territory annexed by the Belkan Empire, left heavy resentment among the Aurelian populace, served as a catalyst for Aurelia's part in the war. A extreme thirst for revenge, had swept through Aurelia. The most common sentiment among Aurelians was to avenge the territorial and military losses at the hands of the Belkans. The Belkan Chancellor at the time, Manfred von Wernher, the ancestor of future founder and CEO of Wernher-Noah Enterprises, Wilhelm Wernher, was wary of Aurelians thirst for vengeance and attempted to keep it in check. But whatever deals he made with the Aurelians died when the pro-Imperial government was dissolved and his successor cut most ties with their neighbor. The new government in Griswall cut almost all ties with Belka and recovered from its defeat, but they felt insecure with Belka's stronger military power. A second example of an unresolved territorial disputes is the Osean War of 2184, where the Osean Federation annexed a portion of Belkan territory, the Great Lakes region, which was home to a plethora of natural resources.

Greed was another well-known factor. The discovery of new deposits of Dust and other natural resources in some neutral and Pact states lead to the UP wanting access to these valuable resources while others wanted to add those resources to their wealth. The same could be said for some of the Allies, as they needed Nature's Wrath to properly defend itself from the Grimm.

An intricate and complex web of alliances was another variable that lead to the war, with nations having mutual defense pacts with another lead to the conflict's steady escalation. The mutual defense pact that consisted of Ugellas and Verusa was, by far, the most surprising, as the two nations had fought a bitter war with each other until 2217, where the Yuktobanian Revolution saw a communist regime rose to power in the former empire. This, ironically, gave both imperialistic and militaristic states a common enemy to fight. The Kingdom of Mantle, the Imperial Republic of Belka, the Dominion of Emmeria, the Kingdom of Sapin, the Recto-Gebetian Empire, and Vacuo were members of the Unified Powers while smaller states that joined later were allies of major UP states. The Grand Pact of Freedom was opposed to the UP's ideals and was made up of the Kingdom of Mistral, Kingdom of Vale, and other pro-democracy nations. The power vacuum left by the decline of the Desoas Empire was also a major factor of the Great War as some of its territories had secured their independence over the previous century.

Another more major issue that lead to the war was the very concept of individualism itself. In 2213, a coup d'etat against the royal family and noble houses of Mantle led to the establishment of a military junta in the capital of Atlesia led by Victor Franz, the General of Army of Mantle, and Erwin the First, the puppet that had put in place of King Norman the Fifth, formerly the lord of House Manfred. While effective at dealing with the creatures of Grimm, it increasingly came apparent that they did not have the best interests of its people at heart as it began enforcing its United as One Policies on them, but propaganda kept the majority of the civilian population in line and compliant. Predictably, General Franz and his subordinates had ordered the suppression of self-expression and the destruction of art considered 'unpatriotic' in an attempt to enforce total uniformity on Mantle. As the years went by, Franz set his sights on the rest of Remnant and sought to control it, by either diplomatic methods or, most preferably, military force. In between 2219 and 2231, he made alliances with Belka, Vacuo, Emmeria, and Recta-Gebet, this alliance was later joined by the Erusean Empire and the Ugellan-Verusan defense pact due to their respective treaties with Vacuo and Belka.

I think that the Great Remnant War was essentially a combination of World Wars 1 and 2.

Here is a timeline:

Great War (2234-2245)

Post-War conflicts (2246-2289)

•Cold War (2246-2287)

•Mantle's collapse and the Rise of Atlas (2271-2275)

•2272 Good Friday War and 2275 ENP Rebellion (2272-2275)

•Yuktobanian invasion of Ughanistan (2281-2285)

•Kalugian and Romian Uprisings (2286-2287)

Faunus War (2291-2296)