Close communication with ancestors and belief in the efficacy of their powers are closely associated with minkisi in Kongo religion. Among the peoples of the Congo Basin, especially the Bakongo and the Songye people of Kasai, exceptional human powers are frequently believed to result from some sort of communication with the dead. People known as banganga (singular: nganga) work as healers, diviners, and mediators who defend the living against witchcraft and provide them with remedies against diseases resulting either from witchcraft or the demands of bakisi (spirits), emissaries from the land of the dead.