After Sky Scar's Cosmic Energy reached the Unity of Heaven and Man stage, he realized that human life could not be immortal. No matter how advanced the Metamorphosis Technique is, the human body will eventually age, especially the brain. The Metamorphosis Technique is just a method of regulating body functions, and at a certain point, the brain will no longer be affected by this regulation and will still die. Even in Sky Scar's current state, he cannot say he will live forever, yet he is sure to live longer than ordinary humans.