Martial Peak - Ch. 686 - Meeting Old Man Li Again

[MangaDex]

 

[Kaarme]

He does know some uses for it, such as a great increase in defence against soul attacks, especially takeovers. It also helps with alchemy a lot, which is why the coffin zombie was collecting people with it, to send them to the closed tiny world of the demons, who need the services of a master alchemist.