There are several levels of immortality:

  - Simple immortality: A being that cannot be harmed by normal means. It can die in theory if it were to somehow be harmed.
  - Death-proof immortality: A being that when killed will come back to life.
  - Undying immortality: A being that is protected from death by the laws of creation.
  - Meta-creation immortality: A being that exists outside of creation and thus is beyond the construct of death entirely.