Hae Soo is a fictional character from the South Korean television series Scarlet Heart: Ryeo. She is portrayed by actress IU and is known for her strong-willed and compassionate nature. The story follows her as she travels back in time to the Goryeo Dynasty, where she becomes entangled in the lives of the royal family. In the series, Hae Soo develops complex relationships with several princes, including Wang So, who is known for his brooding personality. Her character navigates the challenges of love, loyalty, and political intrigue, making her a central figure in the unfolding drama of the historical narrative.