What is the identity of the protagonist in Old Fuofuda?

In the past, the protagonist was a big demon. The old novel ofuda tells the story of Chu Qiguang, the hero, crossing into a different world where demons run rampant. At the same time, he was accompanied by Golden Finger's Secret of Purple Mansion. In this ancient time when demons were rampant, he thought he could be a great warrior to subdue demons, only to find that he was the great demon.