Musoka is a water-divinity, the junior sister of the serpent Mukiti, who presides over the quiet upstream shallows of the winding river near Tubondo. When Mwindo journeys through the waters toward his aunt Iyangura, Musoka raises a barrier or dam to forbid his passage, insisting he cannot pass before her elder brother is informed. Undeterred, the hero burrows beneath her dam and continues, marking her as one of the succession of guardian powers who test him at the boundaries of the aquatic world.