The Pre-Heaven Skill is the highest level Quanzhen sect internal cultivation technique. In all of the Quanzhen sect, it is believed only Central Divinity Wang Chongyang, the founder of the Quanzhen sect, knows the skill.
There are two known practitioners of the skill, Central Divinity Wang Chongyang and South Emperor Duan Zhixing. Wang Chongyang, the creator of the skill taught Duan Zhixing the technique in exchange for the Yi Yang Finger. Knowing that he didn't have much longer to live, Wang Chongyang used the exchange as a way to teach Duan Zhixing the Pre-Heaven Skill because when the Duan Royal Family's Yi Yang Finger is powered by the Pre-Heaven Skill's internal, it is the Black Star and perfect counter to West Poison Ouyang Feng's Toad Stance.