Prologue: Ode to the Unending War.
According to the declassified documents from the Office of the Japanese Imperial Shogunate, at the 12th day of the third month of the year of the wood snake, or in the renewed central calendar, March 12, 1545, Kirin Lord Iwasawa Hiroshi, signed the declaration of total war against all non-aligned and non-neutral lands past the Onnoki gulf. This was a mere two days after the total destruction of much of Kise province's major cities and the collapse of the ruling lordship government. A proof that Kise's futile attempt to take over the Southern Triad for itself was not even treated as a threat by the rest of the alliance.
Throughout the Sengoku era, it wasn't out of place for armies numbering in the tens of thousands at minimum and hundreds of thousands at maximum, to meet and do battle with each other either purely due to the whim of their ruling lord, or the naïve wish of the people to wage war for the sake of spoils of war.
This war isn't one of those.
For the first time in the country's history, due to the electoral powers and rights given by the Kirin Lord upon his people, a sense of national pride wounded by terror attacks and camaraderie for the people they are allied with who has died fighting a traitorous land and kin, it let the country be awash in a unified idea of bringing the fight to their enemies. An idea immortalized by a chant later used in propaganda materials.
"To their land, to their people, to their blood."
Thus started the war that would change this world as a whole. The War of the Otherworlders.