As far as Yanlong knows, this "Swallowing the Sky Golden Body Technique" is one of the only complete exercises from the prehistoric period that has been preserved to this day! When Yanlong was undergoing his second heavenly tribulation, the people who attacked him were running for the "Swallowing the Sky Golden Body Technique".
Shen Jue", but was killed by Yanlong risking his life! This secret was also preserved.