One of the theories is that the mother of a man called Yasaburo was transformed into a hag, and another is that a hag bit Yasaburo's mother to death and transformed herself into his mother; and much more.
弥三郎（やさぶろう）という男の母親が鬼婆に変貌したという説や、鬼婆が弥三郎の母を食い殺して自らが弥三郎の母に成り変わったという説など、諸説がある。