Pumbu a mfumu is the second of the two great chiefly masks of the Pende of the Kasai, the masked spirit of the chief's executioner (ngunza ya fumu). Where Gipogo embodies the protective, life-giving face of chiefship, Pumbu embodies its lethal, executive face: by fusing with the chief it represents the branch of his office that must deal with war and execution. Ownership was the prerogative of paramount chiefs alone, and the mask was brought into play in response to social crises, when the chief needed to assert control. Its performance is the kuhala kua ngunza, the executioner's dance, in which the masker advances with a halting backward stutter-step, flourishing a blade, building dread as the executioner nears his victim. Among the Central Pende, Strother notes, Pumbu has been developed almost into a village character, his dance interwoven with songs recalling the folkloric execution of a stranger at a chief's investiture. He was studied alongside Gipogo by de Sousberghe and documented in detail by Strother.