Most often times in media a group of protagonists are mortal, so they are susceptible to death and injury of any kind within the story. Except if there is one person on that group who is an immortal being.
The token immortal is a member of a group of characters who possesses some form of immortality. They usually appear in works having any kind of supernatural, magical, or sci-fi setting. Having immortality may be seen as very unique for the setting and therefore a group of characters may want to keep them around.
Their purpose in the story can vary. If it is a group involved with fighting, chances are their purpose is to partially function as a meat shield, since they cannot die in any way.
The token immortal may also exist to function as a huge encyclopedia of knowledge and skills due to them having been around for ages and having witnessed many things to the point that nothing may faze them.
- Hetalia: Axis Powers: While all of the nations live exceedingly long lifespans and can survive things that would kill a human, they can die. Only China is outright confirmed to be immortal, and is older than any other currently living nation-tan.
- Naruto has Akatsuki member Hidan, a shinobi who has Complete Immortality from his Religion of Evil's practices and forbidden ninjutsu. However, due to his Hot-Blooded Dumb Muscle personality, Leeroy Jenkins fighting style and limited set of Awesome, but Impractical abilities, he is able to be dealt with relatively easy on his own since his immortality does not allow him to reattach his own body parts, needing help from Kakuzu to reattach them for him.
- Deconstructed in Yona of the Dawn. Zeno was part of the first generation of Dragon Warriors two thousand years ago to protect King Hiryuu. He was essentially made to be a meat shield who could never die but was useless unless fatally wounded. However, as the rest of the Dragons weren't immortal, he had to go through the pain of feeling them die. Currently, the group hates it when Zeno has to use his powers, and will go to great lengths to stop him, as they don't want to see him suffer or think of him as a tool.
- The roster for The Avengers has at various times included the gods Hercules, Gilgamesh, and Thor, and the Eternal Sersi.
- Orlando has been in multiple incarnations of the League of Extraordinary Gentlemen, formed centuries apart. The first time Mina looks through the records, she assumes it's a Legacy Character situation. Orlando winds up sharing his/her immortality inducer with Mina and Allan.
- Some members of the team (or enemy teams) have specific mutations or abilities that render them immune or resistant to aging.
- Wolverine is the most stand-out example; for decades (in Real Life), it was unknown just how old Wolverine was, but it was known that he had at least fought through one or both of the World Wars and he is still extremely healthy in various far-flung Bad Futures. It wasn't until 2001's Origin that it was revealed he was born in the late 19th-Century, thus not quite immortal, but extremely long-lived.
- Two other notable examples are Mystique and Sabretooth, who have both an been X-Man and a member of the Brotherhood of Evil Mutants. No one knows exactly how old either are, but both are at least over a century in age (even having a child together far in the past). No limit is ever given on how much or how little they age, but either way, they can both live a long damn time.
- Ruby Summers, a future daughter of Scott Summers and Emma Frost, stopped aging after she chose to permanently remain in her Ruby form. She's been in it for so long that it's unknown what would happen if she turned back human or lost her powers—maybe she'd stay whatever age she was the last time she deactivated, or maybe she'd rapidly age several decades on the spot. But she doesn't ever intend to find out.
- Young Justice: At the team's inception, Superboy was biologically immortal, as a genetic anomaly had forced him to remain permanently locked at 16 years old. This was at first an existential crisis to him, as he had to face the fact that he'd never grow up and become the next Superman. This was later fixed after a magic spell forced all adults and children to "reverse" ages, but threatened to kill Superboy since his body rejected it until his genetic defect was "cured".
- In the audiobook series Cheese Runners, the chief engineer is Zook, an immortal whose primary character trait is being suicidal due to the fact that he has lived for so long. Venturous Smuggler Captain Fisch is constantly having to either talk him out of killing himself or finding some preposterously dangerous thing for him to do to keep him entertained.
- In Far Rainbow, Camill is the only resident of the title planet who isn't particularly afraid of the P-Wave, because, as one of the few successful human-machine mergers, he is functionally immortal. Dying and coming back is painful for him, but as he tells Gorbovsky, "Tomorrow morning, I will wake up on a empty planet, all alone, surrounded by snow and ash."
- In The Hobbit and The Lord of the Rings, elves are described as immortal. The only elf in the main party of both books is Legolas.
- The Marvel Cinematic Universe has a few examples:
- Thor is this for the Avengers. Granted, Hulk is stronger, however Thor has been around for Millenia and is the Norse god of thunder to boot.
- Apparently Star-Lord was one for the Guardians of the Galaxy, being the half-human, half-Celestial son of Ego. It turns out, he was secretly immortal until he killed Ego, destroying his own power source and ridding him of anything superhuman.
- Babylon 5: Lorien is immortal and joins the main characters to help end the shadow war. Babylon 5 spends a lot of time setting up the incredible gulf between the "Younger Races" (mankind etc.) and the First Ones. While in most science fiction "the ancients" suffer from rapid villain decay even if made out to be vastly superior technologically at the beginning, in Babylon 5 there is never any question of the Younger Races challenging the First Ones. They can turn planets to rubble by the dozens and wipe away the Younger Races' fleets without even trying very hard... And to Lorien, they are still just barely more than children.
- Common in the Buffyverse:
- Doctor Who:
- In most series, the Doctor is the only near-immortal Time Lord in his group, with the exception of Romana, a Time Lady who accompanied the Fourth Doctor and even regenerated in his company.
- Captain Jack Harkness became this to Doctor Who after being revived by Rose Tyler possessed by the power of the TARDIS at the end of "The Parting of the Ways" (Season 1 finale and the swan song for the Ninth Doctor), becoming him since a simple human to an immortal. Later, he became one of the companions of the Tenth Doctor and later he has his own crew in the spin-off Torchwood.
- Downplayed in House of Anubis. Victor isn't genuinely immortal- but he's taken the elixir of life longer than anyone else in the society, resulting in him looking middle-aged when he's actually 95, slowing down his own aging process significantly.
- Misfits: Nathan finds out the hard way after a Mass Super-Empowering Event that he's become immortal, but takes it in stride after getting dug out of his own grave. He rarely bothers to use it to shield his friends from harm, though, as he explains, just because he can heal from any injury doesn't make them any less painful.
- In Death Stranding, Player Character Sam Porter-Bridges is a "Repatriate", meaning when he dies, he can return to his body from his "Beach" (basically a personalised purgatory) and come back to life. However, this doesn't prevent his death from causing a "void out" (a massive explosion caused by a human corpse becoming a BT), meaning that every time the player dies, it leaves a crater in the game world.
- Onmyōji: Yaobikuni, who ingested mermaid flesh to become the only immortal among the game's four protagonists. This becomes important to the plot at one point, where she's the only one truly Barred from the Afterlife while the rest of the group, while still alive, can enter the afterworld by way of magic.
- Soul Series:
- In the original timeline, Maxi became supernaturally-empowered after he was wounded by shards of the Soul Edge. Thus, when he began traveling with his companions Kilik and Xianghua again, he had basically become immortal.
- Inverted with Ivy, who was the Token Good Teammate amongst the Big Bad trio of herself, Astaroth and Nightmare. Of the three, she was the only one who wasn't immortal—at the time. After leaving the group upon realizing she was being used, she later became immortal after a confrontation with her father, where she absorbed all of the souls he himself had stolen and became immortal herself.
- Disenchantment has Luci for the main protagonists, an immortal demon from Hell with various powers at his disposal. As of "Stairway to Hell", this trope no longer applies.
- Implied with Twilight Sparkle from My Little Pony: Friendship Is Magic. She started out as a normal unicorn but became an alicorn later on. In the series finale, she's shown young looking despite her best friends all aging by several years.
- Regular Show has Skips, who has been immortal for centuries thanks to the Guardians of Eternal Youth and is one of the park workers.
- In the Coon and Friends Trilogy of episodes for South Park, Mysterion (Kenny) reveals his secret that he can never stay dead and that everyone around him forgets his death after his rebirth each day.
- Steven Universe:
- Possibly inverted with Steven. By default, all Gems are immortal and never age from the moment they're created, including the veteran members of both the Crystal Gems and the Diamond Authority. Steven, however, being a Half-Human Hybrid, grows up from a baby to a teenager through the course of the show. It's speculated that he may stop aging at some point, but no one knows for sure at the moment.
- Connie is definitely an inversion, however. As an ("honorary") member of the Crystal Gems, she is the sole full-fledged human.