Her name is Feishen, and her name comes from Bai Juyi's "Langtaosha Ci": Hatred is not as good as tide and trust, and you will realize that the sea is not deep until you miss each other.
She is sick. Delusion, also known as delusional disorder, is a mental illness. In layman's terms, she is a lunatic and does things that are seriously unreasonable.
At first, she couldn't believe that she would suffer from this kind of disease at this golden age of more than 20 years old when she was exuding beauty. She had no symptoms and no cause. Just like that, suddenly, countless voices rushed to her ears, chattering in the eardrums: "You are sick, you are sick, you are sick..."
As she kept thinking about it, she realized that she was really sick. She was so sick that every dream she had every night was filled with the shadow of her illness. However, she was extremely repelled by the disease in the real world, and she became more and more addicted to her sick self in the dream, and she refused to wake up.