Among the many kingdoms (fondom) of the Cameroon Grassfields, the central fon (chief) and a number of secret societies are responsible for the social rule of each kingdom. In close counsel with Kwifor, Ngwerong, Mfu and Takumbeng (the social organisations of village elders, nobles, princes and elites) the fon must maintain spiritual and social order and is responsible for peaceful collaboration between neighbouring villages. The Kwifoyn (called Mbansie in some sources) society is responsible for upholding the laws of the Bamum kingdom; members mediate conflict and implement criminal justice when required.
To highlight the wealth of the fon and the status of participant members, an annual Nja harvest festival is held during which sacrifices are made at the graves of past fons. Held in December or January, the dry season, the Nja festival is a display of hundreds of anthropomorphic (human) and zoomorphic (animal) masquerades dancing through the palace courtyard in single file. The dancers and their masks are a visual representation of Bamum society and social rank.
Tu nkum mpelet helmet masks are paraded by the most senior members of the Kwifoyn society.