Bujian Shang Xian Sanbai Nian

There are thousands upon thousands of demons in the world, and half of them reside in Zhaoye City. As for the other half, they all died in northern realm of Canlangli, under the control of the Celestial Immortal Xiao Fuxuan. Only one demon remained alive there, imprisoned for the last twenty-five years. He is Zhaoye City's former lord mayor, Wu Xingxue.

(Source: Kuaikan, translated)