NOVEL NEXT Immortality
Semi-Immortality: Users of this ability never age, and as a result, they stay young forever or at least never suffer the ravages of aging. Because of this, the user will always be at their physical prime.
Example: A vampire will never age or die naturally but they can be killed easily.
Immortality: Users possess immortality: an endless lifespan, as they can never die, never aging, and have a powerful regenerative ability. They can survive and quickly recover from anything you throw at them so long as it does not cause instant death. They usually have an elemental achilles heel that is unique to them that can kill them without completely destroying them.
Example: The Norse god Baldr was granted a special type of immortality that protected him from harm from all things in creation. He was killed by a mistletoe arrow the one thing in creation that he was not protected from.
Absolute Immortality: The users are absolutely immortal, and cannot die, age, get sick, or be permanently wounded, and, their minds and souls are as immortal as their biological bodies. Any injuries the user suffers will immediately heal, even if the user's body is blown up, disintegrated, or destroyed to the sub-atomic level, they will still return to life so long as a cell remains. The only weakness of this ability is that if the user's ability to heal is overtaxed they will enter a state of dormancy where they do not heal or resurrect for years or centuries. Users can still be killed if erased from existence
Examples: Zamasu was a lesser god of the Dragon Ball Super World that could not be killed. Even in death he would always regenerate endlessly and was only defeated when both he and the world were erased completely.
Reliant Immortality: The user is immortal, their existence tied to an object, soul fragments, or even a person or concepts. So long as these things exist, the user can never die.
Examples: In Harry Potter the dark wizard Voldemort was unkillable because he hid 7 pieces of his soul all across the world. They kept his soul tethered to the mortal world and he would always return in one shape or form until they were destroyed.
Concept-Dependent Immortality: The user is Nigh-truly immortal as their existence is tied to a certain concept. As long as that concept exists, the user will never truly die in any way. The only way for them to be killed is to be taken to a reality without the concept and they cease to exist. Even upon complete erasure the user may return and resurrect if the concept is brought to the reality they died in.
Example: Barbas is a demon of fear in the show Charmed. As a demon tied to the concept of fear, he can not truly be killed and will always return so long as humans feel fear. When the world was magically changed and there was no fear he lost all his power and was killed permanently.
Divine-Absolute Immortality: The user's existence and soul become completely free and independent of even the concept of reality, making them unbound to the subjects of life, death, and manipulations. The user's existence is eternal to the point that they would not only continue to exist even after the end of time and all of existence but would also remain completely unaffected and unchanged by it, essentially outliving time itself and everything else. Also, the power cannot be removed, erased, destroyed, or manipulated by any means. Overall, only truly Omnipotent beings like Primordials can kill the user or even affect their immortality. In some cases, the user's existence can overpower almighty laws thus rendering their immortality truly perfect and absolute in every sense. As an added benefit the user has no physical, spiritual, or mental weaknesses, giving them immunity to everything that may harm them, essentially making them invincible and immune to anything. The only death for these beings is to be consumed by a higher-level deity or the user choosing to reincarnate into a completely new life with a much newer or permanent version of themselves while retaining none of their previous memories but still having their capabilities in all their lifetimes.