In A Long, Long Time Ago And Essentially True, one of the main characters, Beata, is constantly referred to by the nickname "Baba Yaga."
Baba Yaga is a popular figure in Slavic folk tales (Slavic language map). Also known as the "Old Woman of Autumn," her origins can be traced back to the ancient Slavic goddesses of birth and death. The derivation of her name is not clear: "baba," is an abbreviated form of the word "babushka," the Slavic term for an old woman or grandmother; but the origins of "Yaga," are more muddy - possibly it is a corruption of "yagat" (to abuse or find fault), possibly it is from a Proto-Slavic word meaning lazybones, or it could simply be a diminutive of the Slavic name Jadwiga (a Polish variation of the German name Hedwig).
A powerful witch, she's generally depicted as a hideous crone, with a long, warty nose, dirty, stringy hair, and steel teeth that make a fearsome noise when she gnashes them. Her mode of...