Oniga's past is bloody; known for its rapid expansion and invasion of other lands early on in its life, it was believed to have become a warring state. The multitude of areas it took over gave it much land, but it did not have the ability to enforce its power in all of these areas. Furthermore, the people were oppressed and pressured by the army, causing much civilian disrest. During the reign of Tennou Myoga, the breaking point came. A revolution erupted in Oniga following the assassination of Tennou Myoga; the Empire's soldiers, fighting the people and Karaten's mages on two fronts, were eventually overwhelmed. More details can be read in Oniga's Revolution.
While there is farming land in Oniga, it is not enough to meet the needs of its people, and so Oniga's trade with other countries is its lifeline. In exchange for mostly food and lumber, Oniga trades its fine weapon crafts and hires out their soldiers to do jobs in other lands.
Religion in Oniga is generally centered around paying homage to protective spirits such as Seiryuu.