Gu Zhen Ren
Tai Bai Yun Sheng is like a version of Ma Hong Yun that isn't a complete scum of the earth harem wh*re. All the luck without the annoying harem tropes that come with it.
I think like Tai old man will create the gu Fang Yuan steals the Recipe goes back in time.Then this time the one who wants to become Immortal is Fang Yuan.He gets help from Human qi Gu the Divert disaster Gu and Voila The best Rank 6 Immortal is Born.Then gets the Gu worms from Old man Tai because He is Immortal now and look volume concluded. This is just my guess. LOL