The protagonists of the story are two sisters, one is a fairy and the other is a demon. Later, they become a god and a demon. They fall in love and kill each other. On the way to becoming gods and demons, they experience love, family, and friendship... This is a world where the human world, the fairy world, and the demon world are three pillars apart. The human world is the most complicated place. Not only are there natural humans, but all living things can transform into human forms and exist in the world as long as they have strong thoughts and enough practice - they are monsters. There are good and evil demons. Good demons can coexist peacefully with humans, while evil demons will harm living beings, absorb their souls to enhance their own magic power, and then transform into demons. Demons gathered in the human world, forming a new force and carving out their own territory - the Demon Realm. However, no one knows exactly where the Demon Realm is. Immortals live in the sky. They are born to protect the peace of the world. This is their mission. As the main force of the immortal world passed down from generation to generation, the gods are endowed with natural divine power. Their responsibilities of killing demons are also more arduous.
Concept: Sisterhood, love between life and death