"Wonderful then." Ling said, gesturing at his talisman "This is the 誓言护身符 Shìyán hùshēnfú. The talisman of oath. It has been blessed by three thousand years of demons making its magic unbreakable. Any who swear an oath to the wearer is bound by reality it's self, as is the wearer. For years scholars have sworn their oaths to my ancestors and been bound. This is how we have kept our secrets. I ask you humbly if you would consider offering an oath, so that none can steal secrets from your lips?"