The most memorable Hellboy villain may not promise the same level of apocalyptic destruction as the Ogdru Jahad or the Queen of Blood, but Russian witch Baba Yaga has a personal grudge against our hero to match Gruagach's and exists in a world that's bizarre even for Hellboy. Part of this comes from the real folklore surrounding the Baba Yaga, a popular figure in Russian mythology who also crops up in Neil Gaiman's Sandman amongst other stories. From that centuries old tradition Mignola has taken Baba Yaga's chicken legged house, her flying pestle and mortar transport, and her control over Koschei the Deathless, whose soul she has hidden inside an egg, inside a duck, inside a hare, inside a goat (as you do). Mignola embellishes these elements to create a Baba Yaga that is essentially the spirit of the Russian nation, enduring unkillable as long as it does. Despite losing an eye to Hellboy when he catches her eating local children, Baba Yaga always keeps coming back for more. Powerful and persistent is a dangerous combination for a villain and you know that sooner or later she will succeed in her aim of taking an eye for an eye.