From WikiPilipinas: The Hip 'n Free Philippine Encyclopedia
Manggagaway is the Tagalog goddess of sickness and one of Sitan's helpers. She is responsible for the occurrence of disease. She is said to disguise herself as a healer, roaming the countryside not to heal but to induce maladies with her charms. Her followers were witches or medicine women, who is also called manggagaway. They have the ability to cure or induce sickness using their earth-wisdom for herbal healing or poisoning.