I've Traveled Through Time, Still Want to Become an Immortal?

As a mortal who travels to the world of immortality, my only way to survive is to accept a disciple. The disciples all have amazing backgrounds: The exiled empress, the fallen swordsman, the reincarnated demon... In order to deter these evil disciples who may kill their master at any time, I package myself as a hidden immortal. My life is tied to their cultivation; Their loyalty is tied to my acting skills. They were testing me day and night, and I was always pretending. Every time they get stronger, I get safer. Go ahead, geniuses, the path to eternal life as a teacher lies under your sword.