The Origin of the Master? the Heroine's Own Secret?

Is it possible that the master was also seriously injured in the upper world of immortality, and now he is hiding in the lower world of cultivation, cultivating his character, and working as a free-range apprentice to hide the big secret? And his previous life was discovered, so the apprentices in his previous life were targeted and died tragically one by one. What is the secret of the heroine?