Baba Yaga (pronounced BAH-ba YAH-guh), the Queen of Witches, is perhaps the greatest witch in existence. She has a hundred schemes on Earth (where she originated), Triaxus, Golarion and across the Great Beyond alike. In 3313 AR, she invaded Golarion, declared war on the Lands of the Linnorm Kings, and established her realm of Irrisen after the 23-day-long Winter War.
Baba Yaga's first appearance on Golarion was centuries before her invasion of the Lands of the Linnorm Kings. She and her Dancing Hut appeared in the dense forests of Iobaria in western Casmaron and maintained a low profile, conversing only with fey and occasionally centaurs. When rumours of a powerful arcanist spread in those early days, however, an Iobarian warlord named Kostchtchie visited Baba Yaga full of demands to be made immortal. As punishment for his rude affront, Baba Yaga granted him immortality, but twisted his form into that of a deformed giant, and hid a portion of his soul in a powerful artifact called the Torc of Kostchtchie. After Kostchtchie's defeat and humiliation, the warlord fled Iobaria to the Abyss, where he eventually became a powerful demon lord, but never forgot his ire toward Baba Yaga.
Baba Yaga then turned her attention to the construction of Artrosa in the Deeprun Crevasse, a huge monument representing a triple aspect of Baba Yaga's personality. Once completed, Baba Yaga left Golarion for a long while, with but a few revisits to quickly check her minions, only returning more permanently in 3313 AR.
The winter of 3312 AR was terribly bitter, even by the incredibly harsh standards of northern Avistan: warriors who left their swords outside overnight would find that the cold had shattered them by the next morning. As if the cold were not strange enough, the northern lights were so bright and sustained that they were mistaken for daylight. These events would later be seen as omens of the terror that was to come.
The following year the Witch Queen Baba Yaga invaded the Linnorm Kingdom of Raemerrund and the Djurstor Confederacy from over the Winterwall Glacier, bringing with her an army of ice trolls, cold fey, frost giants, white dragons, and other evil creatures. King Jarguut and the thanes of the Confederacy were too divided and weakened to offer any serious resistance, and the Winter War ended in the defeat of the Ulfen forces in only 23 days.
Once the Ulfen armies had been defeated, Baba Yaga installed her eldest daughter Jadwiga as queen of the new nation of Irrisen, and divided it into five provinces: Bleakmarch, Feyfrost, Hoarwood, Thronehold, and Wintercrux. After this was accomplished, however, the Witch Queen seemed to lose interest in Irrisen and abruptly departed Golarion.
Baba Yaga was not heard from for nearly a century after the founding of Irrisen. In 3413 AR, Baba Yaga returned to Golarion and removed her daughter, Queen Jadwiga, from the throne, placing her younger daughter Morgannan in charge. She left again shortly thereafter, taking Jadwiga with her along with the first generation of Jadwiga's offspring. This process was to reoccur every 100 years like clockwork, and continues to this day.
As of 4713 AR, she has seated someone she introduces as her granddaughter on the Irrisian throne: Anastasia Nikolaevna