Song: Gunjou Rein (Ultramarine Rain)
First appeared in Imagination Forest. A half-human, half-Medusa woman who was Mary’s mother. She lived in the forest with Mary. Fearing Mary will be rejected by humans, she kept her from going outside into the world. One day, Mary disobeys her and goes outside only to get attacked by humans. In that situation, she used her power to turn him into stone in order to protect Mary. However, the strain on her body was too great for her to bear, resulting in her death.
Regarding Heat Haze.
(Source: Vocaloid Wikia, pixiv Encyclopedia)