Baba Yaga

Baba Yaga is a popular character in Russian folklore and fairytales.  She is an old, scary witch with iron teeth who lives in a hut deep in the forest. Her hut was a character of its own too.  Her hut had its own legs that it could use to walk and move around the forest with; it also would often shriek and scream, and would only cease its noises when a secret incantation was muttered to it.
One would know if Baba Yaga was near because her presence caused a strong wind to blow, the trees around to creak, sway, and groan, and a group of shrieking ghosts and spirits to appear.  Baba Yaga was often seen with carrying a broom made of silver birch, which she did not sit on to fly.  Rather this broom was used to sweep away all traces of herself.
Baba Yaga had 3 faithful servants: the White Horseman, the Red Horseman, and the Black Horseman. Each horseman represented a different part of the day; the White represented the dawn, the Red the Sun, and the Black the midnight.
Although she is mostly seen in stories as a scary witch, she is sometimes portrayed as a helper and voice of wisdom.  When seen this way in stories, she would usually give wisdom or magical gifts only to the heroes who were pure of heart.