The Ageless

This character is immortal, but not because he is Nigh Invulnerable or can regenerate any injury, even From a Single Cell. He is immortal because he doesn't age, nor does he usually sicken. This character will never die from natural causes.

However, he is just as vulnerable to injury as a normal person, and any normally fatal injury will prove fatal to him as well.

This is frequently a racial trait of elves and almost always a feature of robots.

Frequently overlaps with Immortality Begins At Twenty and Life Drinker. Also frequently overlaps with immortality by Healing Factor, to the point here it's more unusual to find someone with a Healing Factor without slowed or stopped aging than with.

Compare Long Lived, Really 700 Years Old.

Anime and Manga

 * Sasori from Naruto, due to the fact that he turned himself into a puppet.
 * The Innovators, artificial humans from Mobile Suit Gundam 00 whose aging is controlled by gene manipulation and nanomachines.
 * Master Roshi and Fortuneteller Baba from Dragon Ball, both having drank from the Fountain of Youth.
 * The case for gods in the Saiyuki series.
 * In Robotech, the Zentraedi apparently have biological immortality due to a protoculture - based genetic engineering, despite having a life expectancy lower than humans due to being a Proud Warrior Race and Martyrdom Culture.
 * The demons of Chrono Crusade appear to be this. There's some indication that they do age, but if so it's very slowly—they look the same age even over a span of 60 years.

Comic Books

 * The Elves in Elf Quest (except for ) do not die of old age, however, sickness occasionally happens, e.g.
 * Many immortals of the DC Universe, including the New Gods and the Amazons.
 * In the titular world of Felarya, everyone has this due to the magical properties of the world. Unfortunately for those who come to Felarya seeking immortality, it it very easy to die there.
 * Doctor Strange got into a fight with Death itself, accepted its inevitability, surrendered to it, and Came Back Strong. He is told that, as a result, "death may only come from without, in battle -- and not from within."
 * From the Marvel Universe, Nick Fury. His brand of immortality stems from the Infinity Formula, for which he was the lab rat during World War 2 (without his consent, he was half-dead at the time, having just stepped on a landmine). The formula took about a quarter of a century to work on his biology, and now, although being nominally 90 years old (born 1917-1918) he is physically in his 40s, 50s tops and will not age another day. He can however be wounded, and presumably killed; nobody really achieved that, since he's Colonel Badass, with an Eyepatch of Power.
 * Fury's Arch Enemy Baron Strucker, the leader of the terrorist organization HYDRA, also has repressed aging thanks to a serum.

Fan Works

 * In I Am What I Am, a Buffy the Vampire Slayer fic by M. McGregor, Future!Willow has halted her aging, leaving her physically in her early twenties even toward the end of the 21st century. Also, it's discovered that Slayers' aging seems to halt at age 20, plus or minus a few years.

Film - Live Action

 * Tom Creo / Conquistador Tomas in The Fountain (also a case of Who Wants to Live Forever? and Literal Genie, respectively).
 * In Indiana Jones and the Last Crusade, drinking from the Holy Grail grants you this form of immortality. There's a downside, however:
 * The puppets in Puppet Master are brought to life by an ancient Egyptian spell found by Andre Toulon. The spell apparently works on humans as well, but they are only invulnerable to aging. This also applies to the puppets as they can be damaged to the point of death.
 * In Time features a humanity that has stopped the aging process, freezing everyone's age and physical abilities at 25. Time itself has replaced money as currency, meaning that the poor live day to day, while the rich can effectively become immortal.

Literature

 * The elves in The Lord of the Rings and The Silmarillion have an infinite lifespan until the world ends, have the vigor and strength of a human in his prime no matter how ancient they are, and do not get sick. They only die if slain. Even death isn't always permanent; after an elf's spirit has spent some years in the Halls of Waiting, if they have thoroughly repented and learned from any sins they comitted, they get re-embodied—this, however, is not an inherent power but a grace provided by the Valar (the godlike archangels of Arda).
 * Morc, in the De Dannan Isles books
 * The sorcerers of the Belgariad.
 * The Immortals of Tamora Pierce's Tortall Universe books.
 * The Amber Royalty from the Book of Amber are mostly this. They are quite tough and regenerate better than humans, but it's a very slow process (it takes four years for, for example). Serious wound definitely can kill them, which happens on several occasions.
 * The Remillard Clan from Julian May's Galactic Milieu series. Each one appears to stop getting older at a different age. They have minor regenerative powers, but they can still be seriously injured or killed.
 * The majority of the Wilds from Trudi Canavan's The Age of Five trilogy fall into this category. The most extreme example is.
 * May be true of Indigo and Grimya - they do not age, but even they don't know whether they can be killed by injury or disease. At one point, Indigo is seriously ill and comatose, and Grimya worries that she will remain delirious forever if the disease "kills" her. (Indigo recovers, and the question is never resolved.)
 * Warbreaker:
 * The Returned can continue to live indefinitely if they are supplied with Breath once per week but are otherwise as vulnerable to injury as anybody else,.
 * Anyone can live indefinitely if they have the Fifth Heightening or above, and in fact it's explained that the Returned immortality works like it does because a Returned has a single, immensely powerful breath that puts them automatically at this stage (People with less than that age more slowly, but the Fifth Heightening is when it stops completely). It's actually better than being a Returned since such people don't need a constant supply of Breath to live (though they do need to gather a lot of Breath in the first place to reach the heightening, their bodies don't consume it once they have it and they can use it indefinitely).
 * The Immortal Vermin of Bruce Coville's Magic Shop series are this type. Bufo, the first of the Immortal Vermin to appear, says he can be killed, but barring such an incident, he will live forever. Jerome and Roxanne, the youngest of the Immortal Vermin, inform the protagonists of "The Skull of Truth" and "Juliet Dove, Queen of Love" of their status as "killable, but otherwise undying". (It may also be mentioned in the updated version of "The Monster's Ring".)
 * In The Last Unicorn the title character is immortal but can be killed by anything from a dragon to a stray arrow.
 * Norna-Gest from the Old Norse Tale of Norna Gest gains this kind of immortality by exploiting the Exact Words of a norn's curse.
 * Dragons in The Obsidian Trilogy are this. They do not age or get ill, but they can be injured and killed. If they chose to bond with a human or elven mage, they will also die when their bondmate does.
 * In The Third Millenium: A History Of The World 2000 - 3000 A.D., The Emortals and Starpeople achieve temporary biological immortality through genetic engineering and the rejuvination procedure; most who don't die by accident will eventually die from a failed rejuvination, but they typically remain youthful to about age 400 - 500.
 * In Lois Duncan's Locked in Time, Lisette and her children have eternal youth but not eternal life.
 * Warlocks and vampires from The Verse of The Mortal Instruments and The Infernal Devices. They stop aging at a certain physical age and stay young-looking and beautiful until they get killed off.
 * The Lord Ruler from Mistborn. He can literally store up youth and health  for later consumption, making him both ageless and virtually impervious to injury..
 * The Alex Benedict novel Polaris has the scientist Dunnager, who was seeking a way to halt the ageing process and was reportedly very close to succeeding when he mysteriously vanished without a trace and his lab burned down..
 * In A Dirge for Prester John, no one who drinks from the Fountain three times will age beyond their third visit.

Live Action TV
"I was 132 years old. I didn't feel it though. In, fact, I felt awesome."
 * Lost's Richard Alpert made a deal with Jacob about 150 years ago, gaining immortality in exchange for becoming a leader to the people of the island. His reasons for asking this?
 * Walter Jameson, from The Twilight Zone episode "Long Live Walter Jameson", was granted this form of immortality in Ancient Greece by an alchemist. He says that he came close to death many times over the centuries due to injuries and disease, "but never close enough".
 * Former Doctor Who companions Ian and Barbara Chesterton were stated in the show's spinoff The Sarah Jane Adventures to have not aged between the 1960s and the 2010s.
 * In the Speculative Documentary Can You Live Forever?, an experimental procedure allows Adam to retain a youthful constitution into old age.

Mythology, Legends, and Oral Tradition

 * Norse Mythology: The Æsir and Vanir are immortal in this way, so long as they continue to eat the Apples of Idun.

Tabletop Games

 * GURPS uses Unaging for immortality. This means only that the character will never grow older or die of old age it confers no resistance to disease or harm. Other forms of immortality require additional powers.
 * In Warhammer 40,000, nearly everyone but non-Space Marine humans and the Tau.
 * In both Earthdawn and Shadowrun, dragons and Immortal Elves have this quality. Dunkelzahn was apparently tens of thousands of years old, and some immortal elves were thousands of years old in Shadowrun.
 * "Longevity: Immortal" is an option for the Life Support power in Champions
 * Likewise, in Mutants and Masterminds, Immunity (aging) is just a 1 point power. If you want true immortality, you need to buy into ranks of Regeneration to account for things like rising from the dead.
 * Dungeons & Dragons has two variants on this trope: Monks and Druids gain the Timeless Body ability, which causes them to no longer age physically (or at least do not get any penalties for aging) until they drop dead when they reach their species' maximum age (thus invoking the Old Master trope). Two races, Elan and the Killoren, have no maximum age and will visibly age to a certain point (venerable age for Elan, old age for Killoren) but never die of old age. Combining either race with either class leads to this trope. There's also an epic feat that adds half your maximum possible age to each age category (a stadium where your character gets visibly older), which has the same effect on them.

Video Games

 * The angels from Tales of Symphonia. The Cruxis Crystals halts the aging process, which is why  still looks more or less exactly the way he did   Even Expheres slow the aging process considerably, in addition to the basic skill upgrades they give. Presea even brings up the possibility of a world of exosphere-preserved Immortals to Lloyd, who gently reminds her that they're
 * Warcraft:
 * Night elves used to have this form of immortality, before sacrificing it to save the world from the Burning Legion. Draenei may also have this form of immortality (Velen is explicitly stated to), or they may just be extremely long lived. Demons also have this type of Immortality (at least one quest states that at least some of them have Type IV as well).
 * Dragons, or at least the Aspects, seem to be undying as well.
 * The 27 True Runes of Suikoden grant this type of immortality, in addition to various abilities based on the aspect of existence that the True Rune governs (for instance, instant death attacks for the Rune of Life and Death AKA Soul Eater, or powerful destructive attacks that also hurt the user for the Rune of Punishment).
 * The Elder Scrolls:
 * The Nerevarine becomes this, as a consequence of . If brought to sufficient heights of power, they can also gain enough regenerative power to leave this trope and enter another.
 * Dragons in Skyrim are this, being quasi-angelic entities who can never truly die unless their soul is absorbed by a Dragonborn. in particular has been waiting on top of the Throat of the World for Alduin's return since the Dragon War many thousands of years ago.
 * Being a Mortal Kombat champion grants this type of immortality until the next Mortal Kombat tournament, which is usually a generation away from the previous one.
 * As the Ultimate Lifeform, Shadow the Hedgehog is ageless, most likely due to the genetic material contributed to Project Shadow by his biological "father," . The reason behind this was that Shadow's creator, Professor Gerald Robotnik, wanted to study immortality and use the fruits of his research to find a cure for his granddaughter (and Shadow's surrogate sister) Maria, as she was terminally ill and suffering from a fatal disease known as NIDS (Neuro-Immuno Deficiency Syndrome).
 * The Dragons in The Legend of Zelda: Skyward Sword are implied to be this way. You find the Thunder Dragon's remains in the present, and travel back in time to find out he's sick and dying. After healing him in the past, he's simply absent in the present, but does show up for the song, so he likely just changed residence instead of dying.
 * Dark Souls has multiple types of beings that are The Ageless. The Everlasting Dragons, the Lords and the Gods, and undead that can maintain their humanity.

Webcomics

 * The fae races of Drowtales, (drow, light elves, faeries) provided they live with enough other fae to generate a surplus of mana. Otherwise they will suffer from mana deprivation and will start to age much like humans do. One audiobook explains that fae do in fact have a finite natural lifespan (implied to be somewhere around 1000 or upwards), but most don't live long enough to ever get close to it.
 * In A Magical Roommate, Oracles live for as long as they want. They can be killed by outside forces, but otherwise, they will live until they decide to die - unlike their counterparts, Sages, who do die of old age.

Western Animation

 * Most incarnations of the Transformers. And good luck with the fatal damage.

Real Life

 * This occurs in Real Life among several different species. The correct term for it is Biological Immortality. Jellyfish are the most well known example.
 * Cracked.com's 6 Unassuming Animals That Are Secretly Immortal lists other animal species that don't die of old age, such as lobsters and turtles.
 * Scientists in Real Life have been attempting this type for a very, long, time. Many believe that humans will eventually attain it. There are a substantial number of people who believe that the first bicentenarian-to-be has already been born, and is possibly already an adult.