Great War (世界大戦) was a war that lasted from 1 September to 2 September, S.1206. All countries of the western half of Zemuria formed two opposing military forces: Operation Jormungandr under command of Marshal Vandyck and Operation Mille Mirage under command of Lieutenant General Cassius Bright. It was the largest war in Zemuria's history; involving more than 2 million people.
- See also: Great Twilight
The Great War began to set once Ash Carbide had shot Emperor Eugent Reise Arnor III, having been manipulated into doing so. Chancellor Giliath Osborne framed Calvard for the attempted assassination after it was revealed that the gun Ash had used to shoot Eugent was of a Calvardian model.
To prepare for war, the Imperial government passed the National Mobilization Law to enlist men ages 19-45 into military service, which also saw the foundation of additional regiments to deal with the surplus of recruits. When the Nameless One was slain in the Gral of Erebos, it amplified the curse to reach all of Erebonia and Crossbell, further strengthening the populace's animosity towards Calvard.
Following the cancellation of the Great Twilight, a cease-fire was negotiated on September 2, one day after the start of the war. Through the collaborative efforts of Marshal Vandyck and Lieutenant General Bright, casualties were kept to a minimum and the cease-fire was officially realised.
Through mass-communication, Eugent Reise Arnor III announced his reinstatement as emperor of Erebonia. He furthermore reiterates to the entire world that the attempted assassination on his life was not the doing of Calvard. Heimdallr governor Carl Regnitz vigorously follows up on his majesty's words by having the Imperial Army withdraw immediately. It was expected that Calvard would follow the retreating army, but this as their military was nowhere near as strong as Erebonia's.
Naturally, Calvard strongly condemned Erebonia and its actions. Calvard had evacuated the area on which the first day of the war took place, so casualties on the Republican side were also kept to a minimum. President Rocksmith, by now at the end of his term, carefully responded to the situation and tried to hold back his dissatisfaction. This was acknowledged by his successor, propagating the demand for astronomical indemnities from Erebonia. Governor Regnitz responded to the matter diplomatically. During the negotiations Liberl, Remiferia and Arteria agreed that Calvard demonstrated strong self control by not invading Crossbell after the imperial army withdrew. The indemnities were eventually paid for by the government, the imperial family, Reinford Group and the Four Great Houses.
Following the imperial army's withdrawal from Crossbell, negotiations started between the imperial government chairman Henry MacDowell. With no regard for the Government-General Security Force, control over the city and area were returned to MacDowell at once. Anxious of another invasion from Calvard, along with the arrest of the governor-general Rufus Albarea, security was reinstated to the Crossbell Guardian Force and civilian volunteers. The Government-General Security Force that disturbed the Orbal Network were soon overpowered. Crossbell was liberated at the hands of volunteers, with key figures from the Special Support Section at its centre.
Not only external, also internal difficulties had to be overcome by Erebonia. The death of Chancellor Osborne, the instigator of the war, caused an uprising of the oppressed noble families, which in turn met with revolt of the masses. The imperial family was tasked to somehow put both parties back in their place. Another challenge the imperial family faced was that the crown prince, Cedric Reise Arnor, had willingly cooperated with Osborne. Cedric, realizing he had been manipulated by Osborne, simply disappeared. Trust was gradually restored in part due to both Alfin Reise Arnor and her older brother, Prince Olivert.
Former governor-general Rufus was arrested for his cooperation with Osborne; however, Rufus had willingly turned himself in to take the blame, seeing that his fellow Ironblood members Lechter Arundel and Claire Rieveldt, head of the Intelligence Division and Railway Military Police respectively, would be needed to restore stability to Erebonia. They were pardoned for their crimes, but both groups lost significant standing and had to be reorganized.
Finally, the Bracer Guild was allowed to finally open its imperial branches again after they were shutdown following the Assault on the Imperial Guilds in S.1202. High-ranking bracers through the continent came to Erebonia to assist in restoring the public order. The guild also learned that Cedric had joined Ouroboros, rumored to be an Enforcer.
Despite Osborne's manipulation to instigate war, there were groups of Imperial soldiers left dissatisfied with the war's swift conclusion, believing that the indemnities Erebonia had to pay were unjust and that the ceasefire was an insult to their strong military. They attempted to restart the war by themselves, but all of these attempts failed.