Наэ Когурэ

She met Yuta years before World War II. When she learned about Yuta's curse of immortality, she tells him a secret about mermaid's ashes. She spread the ashes all around the field of red flowers, causing to bloom all year long, never to wilt or die by season, including winter. She calls the field "red valley". Soon. she and Yuta fell in love and began meeting in the red valley in private. Her fiancée, Eijiro, got jealous of Yuta falling for Nae, but never believed that she would betray him. He learned about Nae's signal of metting Yuta in the red valley, so he went there to meet her. When she arrived at the valley, Eijiro became shocked of her betrayal that he strangled her to death. As years pass, Eijiro learns his mistake and sadness of what he done to Nae. But he learns about mermaid ashes and found it. The ashes brought Nae back to life, but she became a shadow of her former self. When Yuta came back to Nae's hometown with Mana, she plans to reunite with him, but Eijiro prevents it. Sometimes, Nae goes into murderous trances because of her shadow form. But to overlook it, Eijiro is deeply in love with her. As Yuta and Nae reunite once again, she tells Yuta that she is having a nightmare. Then Yuta remembers that there is a village legend that a priestess came to the village, carrying a jar of mermaid ashes. And then a man murdered the preistess, but the ashes went into her mouth, brought her back to life as a shadow, but then wears as she went to the mountains as her deathbed. Nae's affect of the ashes wears off, left her to die once again in the red valley as her deathbed.