I Sleepwalked to the Edge of the Universe and Met My Nemesis

I Read a Book Many Years Ago, Please Give Me the Title.

The protagonist is a mortal fairy, who has experienced in different worlds. The heroine has many clones, and there is also a female demon beside her. I have forgotten the other plots... It seems that there is also a plot where the protagonist comes to the world of snake-shaped beauties and sleeps with their ancestors.