Demons would always be a target of fear in the hearts of humans.
The battle between demons and humans was comparable to the fight between the God race and the Devil clan. They are basically like fire and water.
Before Shen Yanxiao, there was basically no one else who would possibly accept demons.
She was definitely the first human in history to have done that.
"I have already asked them to relocate the lower-ranked demons to the underground city. For high-ranked demons, they should not be easily discovered." Shen Yanxiao had also thought of that aspect and so, she had already allocated those dark element-loving demons to the underground city.
She only discovered the underground city not long ago, and the living condition there was much more suitable for demons to live in.
The demons can choose to be active either underground or above ground in the morning, but they would have to return underground at night.