After Leaving Fusang, I Became a Demon in Distress

As a Fuso demon, I never thought that one day I would leave Fuso and come to a world called the human world. I thought that the world there would be more vast and exciting than Fuso. Little did I know, I actually came from the wilderness to a besieged city. I was trapped in this city, and I would never get out, and I would never be able to recover... Ps: The heroine becomes dark and the second male lead takes over.