Immortality

Introduction
Immortality is the term given to people who cannot die from natural means, whether this be due to longevity, regeneration, or other means.

Types
1: Longevity: Characters gifted with this type of immortality cannot die from natural causes, such as old age or conventional illness, but can be killed by unnatural causes.
 * Examples: Rosalina (Mario Bros), Galactus (Marvel Comics), Ajimu Najimi (Medaka Box), Mew and Mewtwo (Pokémon)

2: Immortality without regeneration: Characters with this degree of immortality can survive a high degree of physical damage, though they cannot regenerate from it either.
 * Examples: Voldemort (Harry Potter), Ganondorf (The Legend of Zelda), Hidan (Naruto)

3: Immortality via regeneration: Characters with this type of immortality can simply regenerate damage, though the usefulness of this type depends on the degree of regeneration.
 * Examples: Doomsday (DC Comics), Majin Buu (Dragon Ball), Alucard (Hellsing), Hourai Immortals (Touhou Project)

4: Immortality via godhood, or protection from a deity: A character that was either granted immortality by a god, or is immortal because of its hierarchical position due to godhood, so that its divine immortality is less a power, and more treated as a consequence of its state of being as a deity.
 * Examples: Future Zamasu (Dragon Ball), Zeref Dragneel (Fairy Tail), Bill Cipher (Gravity Falls), Juggernaut (Marvel Comics), Pontos (Saint Seiya)

5: Deathless Immortality: ''Characters who exist unbound by conventional life or death, or do not exist at all, and thus cannot be traditionally killed. Typically, abilities such as Existence Erasure are needed to destroy them.''
 * Examples: All Dark Area Digimon (Digimon), Sun Wukong (Journey to the West), Ultimate Ones (Nasuverse), Hourai Elixir Users (Touhou Project)

6: Parasitic: The person attains a sort of immortality by bodyhopping, transferring their soul to another body.
 * Examples: The Lich (Adventure Time), Teridax (Bionicle), Jason Voorhees (Friday the 13th), Orochimaru (Naruto), Darth Sidious (Star Wars Legends)

7: Undead: ''Self explanatory. The undead generally double up with other types of immortality, often being impossible to kill through conventional means.''
 * Examples: Jason Voorhees (Friday the 13th), Ghost Kirby (Kirby), Edo Tensei zombies (Naruto)

8: Reliant Immortality: The power to be immortal so long as a certain object, person, concept etc. exists.
 * Examples: Lucemon - Reliant on malice in the hearts of men (Digimon), Voldemort - reliant on Horcruxes (Harry Potter), AIM Burst - reliant on the Level Upper Network (To Aru Majutsu No Index), Fairies - reliant on aspects of nature (Touhou Project)

9: Transcendental Immortality: ''Characters whose true selves exist independently from the plane where they can be killed. For example, a conceptual being doesn't die even if its body, soul, etc will be erased from existence.''
 * Examples: Bard (League of Legends), Tokiha Misa (Notch), Arceus (Pokémon)

10: Meta-Immortality: ''Entities that are not alive or dead in a conventional sense, standing outside the ordinary laws of reality, temporality, and dimensionality (of any number). If it is possible to destroy such a character, it can only be accomplished by a being of a similar or higher existence.''
 * Examples: All 1-A characters