The growing tensions of Erebonia's traditional class society, and the increasingly strained relationship between nobility and commoners, worked through into its imperial army. Within the army there was a 'noble faction', who felt embarrassed and pressured by the rise of commissioned officers of commoner origin.
To recover the position of the noble faction, officers of the army's noble faction started to long for an opportunity to prove themselves. They planned an aggressive invasion of the small kingdom of Liberl, south of Erebonia, and sought an excuse for their invasion.
Around this time Georg Weissmann, the third Anguis of Ouroboros, made use of the anxiety among the noble faction within the imperial army and introduced them to a certain band of jaegers he knew, pointing them toward Hamel. It can be assumed that the general officer Weissmann spoke with was Rudolf Arundel, a general officer within the imperial army but otherwise low-ranked noble who aspired to make a name of himself, who was later found guilty for. 
Brigadier General Giliath Osborne caught wind of their plans, but as a fellow officer in the imperial army could not do more than issue a warning to noble faction. The noble faction responded to his request by hiring jaegers to attack and burn down his house in the outskirts of Heimdallr. The next morning, the corpse of the brigadier general's wife, Kasia Osborne, was found in their burnt down house; the brigadier general himself had disappeared with his 5-year-old son. Immediately following this raid, the noble faction shifted their attention to Hamel.
On the night of April 23rd, S.1192, a band of jaegers garbed in black and armed with Liberlian weaponry encircled Hamel. The jaegers indiscriminately slaughtered everyone in sight, raping the women as they proceeded through the village.[Supplementary 1] Hamel was situated in a remote location with a singular path toward the nearest town, Parm. Jaegers had this path blocked so they could easily find villagers who attempted to escape, such as Karin and Joshua Astray. Karin sacrificed her life to save her younger brother and begged her boyfriend, fellow villager Leonhardt, to look after him.[Supplementary 1]
It was believed that Leonhardt and Joshua were the two only survivors of the massacre[Supplementary 1] until Sen no Kiseki III revealed that Ash Carbide is the third survivor. The local garrison that found Leonhardt and Joshua investigated the ruins of Hamel. They found Liberlian weaponry on the site and three days later, Erebonia declared war on Liberl.
- Main article: Hundred Days War
After almost three months of absence, Brigadier General Giliath Osborne returned to the imperial army. General Vandyck introduced him to Emperor Eugent Reise Arnor III, who gave Brigadier General Osborne full authority to investigate the Hamel incident. During this investigation, Giliath Osborne collaborated with Ouroboros. When the ruse of the noble faction was discovered, the imperial government was thrown into a panic.
Three months after the outbreak of the Hundred Days War, through negotiations with Queen Alicia von Auslese II of Liberl, Liberl and Erebonia agreed on a cease-fire agreement. The Erebonian authorities announced that Hamel had been destroyed in a landslide and that all roads there were to be completely closed off.
Half a year later after the Hundred Days War, Emperor Eugent Reise Arnor III promoted Brigadier General Giliath Osborne to chancellor, the first commoner to assume this position in the history of Erebonia.
- ↑ Sen no Kiseki III, Chapter 1 (04/22).
- ↑ 2.0 2.1 2.2 Sen no Kiseki III, Chapter 1 (04/23).
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Trails in the Sky SC, Finale: "Trails in the Sky".
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Sen no Kiseki III, Chapter 4 (07/17).
- ↑ Trails of Cold Steel II, Finale: "Forward, Relentlessly" (12/31)