Complex sentence: Ysätters-Kajsa was a "wind-troll", that people used to believe in, in the Swedish province of Närke, probably the only one of her kind in Scandinavia.
Split into simpler sentences: Ysätters-Kajsa was a "wind-troll", that people used to believe in, in the Swedish province of Närke. She was probably the only one of her kind in Scandinavia.