Yukiko thought she had a promising future when Setsuji, the leader of Clan Okamoto, and rulers of the cold northern region, took her from her village to have her be one of his wives, calling her the most beautiful he had ever seen. She loved Setsuji and was hard working and loyal, if naive. When she discovered she was pregnant, his first wife Natsuki found out before she could tell the clan leader and framed her for stealing a prized Okamoto heirloom. When she denied it, she was sent out into an early winter storm, banished for a tenday, but only wearing a house kimono. When she looked to Setsuji for reprieve, he turned away and she was sent into the storm to her and her unborn child's deaths.
The storm grew stronger then any had seen in years, the wind virtually wailing and even when it subsided, other storms followed, crippling trade routes. Even when the storms lightened, traders and workers vanished. Every following winter brought more terrible winter storms, many with thunder and lightning. Storms worse then any on record. Some whispered it was punishment for banishing Yukiko and when a mysterious beautiful woman was seen in the distance throwing a traveler to vanish into the snow it seemed confirmed. In hushed tones, some speculated the only reason Natsuki wasn't banished as well was because she gave Setsuji a son, even if her influence was greatly diminished.
Setsuji sent some of his finest warriors to deal with the yuki-onna. The bodies weren't found until late thaw in the spring. Then worse, a revered priest was invited there to help, to banish the evil spirit. Their body was never discovered.
But Yukiko didn't believe herself evil. She simply asked travelers to hold her unborn child made of ice, to show respect to the true heir to Okamoto, but it's weight increased like the responsibilities the clan had failed to uphold in sending the destined firstborn to it's death. When the burden of failed obligations inevitably proved too much bear and her child felt to the ground, she punished those who failed, throwing them into icy crevices with supernatural strength and speed. And those who turned down the privilege to hold such a child were shown no mercy as she was given none.
It was the tenth winter after her death, and she let the worst of the storm pause in hopes of finding someone worthy of taking care of her child. It wasn't long until another desperate traveler braved the storm, and she stayed hidden, waiting until they drew close.
When they approached, she appeared before them in a white kimono unsuited for travel, her extremely long white hair waving in the breeze behind her as if light as snow. She pleaded with them, "Would you please hold Riku, the heir of Okamoto? I must fix my kimono," offering the cloth covered supernatural bundle.