Bai Fan was the Celestial Emperor (Immortal Emperor) and ruler of the Thunder Celestial Realm (Thunder Immortal World / Lei Zhi Xian Jie) prior to its collapse. He was a Third Step cultivator at the early Kongnie (Empty Nirvana / Nirvana Void) stage and the creator of the renowned Six Great Immortal Arts. He is a posthumous figure whose legacy significantly influences later events through his disciple and the inheritance of his techniques. (Source: Wiki)