Humans value the useful, the aesthetically pleasing, and the rare— so it is not surprising that we have a deep fascination with characters, races, or objects that are unique. Be it an artifact from a bygone age, a creature that is the Last of His Kind, or the last knight of an ancient and honorable order. Basically, the more relevant to the story a unique person or object is, the more valuable and worth preserving they are. Friends will fight to protect them, enemies to destroy them, and some even to possess them. Underscoring this is the reverse, that anyone/thing who isn't unique is vastly more expendable.
Maybe this is why both characters, readers, and the author place so much sympathy and interest in these characters. Faceless Mooks may die and be killed by the dozens without anyone batting an eyelid, but the hero will try to spare their boss who is The Last Atlantean Wizard. No one cares about destroying robots or AIs... unless they have a unique and interesting personality. Or say there's a race of goo-people who are all clones and part of a Hive Mind? Finding ways to toast them would become a TV-show.
Relatedly, these unique characters will not just be rare, but powerful. Usually "their kind" is already powerful (which may be why there aren't any more of them left), but being their last representative gives the character a power boost much like the Inverse Ninja Law, sort of an inverse of being a Super Prototype. Although a super prototype is also generally unique in some way compared to the production models, which die easily, so it could go either way.
It's worth noting that these characters are by no means less likely to die. After all, their demise will evoke such a poignant End of an Age nostalgia few authors can resist. Similarly, it's treated as no less a tragedy if they are turned into a Broken Angel, victim of Humanity Ensues or somehow Brought Down to Normal.
In reality, the opposite of this trope is usually true. Many things are unique but not at all valuable, like snowflakes. Conversely, the discovery of a rare and valuable thing is usually followed by replication, optimization, and mass production.
Compare with A Kind of One, A Million Is a Statistic, Endangered Species, Fantastic Nature Reserve, Last of His Kind, Only You Can Repopulate My Race, Power Equals Rarity, and Sparing the Aces. See also Backup Twin, Expendable Clone, The Law of Conservation of Detail, and Men Are the Expendable Gender.
- There are implications throughout the Pokémon anime that Ash's Pikachu is overly strong for its species (well, usually, ignore a certain Snivy), such as its tendency to defeat various Raichu (its evolution that logically should be a stronger version of itself), and Team Rocket's statement in a early episode that it's "way beyond its evolutionary level," which is why they start following Ash around for the entire series and repetitively trying to steal it. It's also one of the few Pokemon shown that dislike Pokeballs.
- Meowth is the only Pokemon shown that physically taught himself to talk. All the rare Pokemon shown thus far that can talk do it naturally through telepathy. He also taught himself to stand on his hind legs, and does evil of his own accord and not for a master, which is rare for a Pokemon. (These last two traits were eventually Retconned to not be so special anymore.)
- Superman started out this way and its common for superheroes to be unique in this fashion because if everybody was like them, they wouldn't be all that super. After decades of encountering other Kryptonians, he was Retconned back into being the last of his kind after Crisis on Infinite Earths for precisely this reason. Now, it's back to being not so unique with 100,000 Kryptonians on a new planet on the opposite side of Earth's orbit, another race (the Daxamites) who have the exact same powers, and probably dozens of other Flying Brick types who vary only a little from him.
- Rewind provides an example of this for Transformers: More than Meets the Eye. In the pre-war era, Transformers were ranked and given rights based on the rarity and flexibility of their alternate mode (essentially making Uniqueness Value a mathematical rule used to establish social class). Transformers that turned into data storage equipment were the most common and were known as the Disposable Class; it's mentioned that, for example, Disposables weren't given access to the high-quality energon. In the present-day, millions of years later there are so few members left and the ones that remain hold so much information, that they are among the few Autobots that can apply for combat exemption.
- The Last Unicorn is so very, very precious to all involved because she is the Last of Her Kind. However, after freeing all the other unicorns she remains unique because she's the only one to have ever experienced (and will remember) human emotion.
- Toothless of How to Train Your Dragon is likely the Last of His Kind, and Hiccup was thought to be the first to tame and ride a dragon, until the sequel revealed that his mother beat him to that years before him. He's still the only one to wound, tame, and ride a Night Fury however, which is quite a accomplishment considering no one had ever even seen one before.
- How to Train Your Dragon 2: The Bewilderbeast is not the Last of His Kind, but the species is close to extinction. As a species, they are unique because they are the only kind of dragon that breathes ice.
- Gill Man from Creature from the Black Lagoon is not just a perfect specimen of his species dating back to prehistoric times, but also the only one left. Which makes the scientists want to study him... something that gets all the more complicated when he starts killing them and blocking the exits. Despite his terrifying actions, he is represented as a lonely creature, kidnapping the Hot Scientist and dying in a rather tragic way. For a B monster movie, anyway.
- Most viewers of Hellboy II: The Golden Army must have felt at least a tug at their heart strings when Hellboy killed the plant elemental, the last of its kind.
- Star Trek (2009) has Vulcan be destroyed, rendering Spock, along with the few thousands of surviving Vulcans, an Endangered Species. Although, interestingly, Spock himself is not unique.
- Spock is, however a half-human, and Nimoy's Spock is the only member from the original continuity in this newly split-off alternate continuity universe. Both Spocks are pretty unique in addition to being one of a few remaining Vulcans.
- A very on-the-nose example in Planet of the Apes (1968). When the astronauts first land on the eponymous planet, they find themselves in the middle of a vast desert. When they finally come on a single plant, their leader, Colonel Taylor, picks it without a moment's hesitation, offering the justification that where there's one, there are others.
- In Dragon Bones, the heroes decide to preserve the life of a basilisk. Sure, it is extremely dangerous, but, hey, it's beautiful, and rare. Besides, they have dragon blood, so maybe that animals seems to them like apes to humans.
- Averted in Harry Potter and the Deathly Hallows: Voldemort has made his Horcruxes out of three of the relics of the Four Founders of Hogwarts, priceless objects over a thousand years old, imbued with powerful magic that is only hinted at. However, they are steadily eliminated one after another — well, gotta catch 'em all to save the world — but one thinks that someone would have reflected, What A Senseless Waste of priceless treasures. It helps that they are keeping alive Wizard-Hitler.
- The Dark Nest Trilogy has the Killiks, several castes of insectoids with a Hive Mind. Naturally, they are extremely disposable, particularly compared to the Joiners, people of other species who were more or less absorbed into that hive mind and retain some vestige of individuality. The Killiks regard themselves that way, since it doesn't matter for them if individuals get lost as long as the hive lives on. A Jedi Joiner shares their opinion; she works with a succession of members of the caste that relays communication best and is extremely fragile. Many of this caste get killed under her, all of them referred to by the caste name, and her reaction is always "Damn it. When does the next one get here?"
- The Buggers in Ender's Game don't even care about individual deaths among their own species, but killing a single Hive Queen is seen as an atrocity about on a level with what humans think of genocide. This is partially due to their Bizarre Alien Biology, as the worker drones aren't sentient, meaning that only killing a Hive Queen actually kills a person. The Blue-and-Orange Morality involved in this culture clash is what started the war; the bugs didn't think humans would mind them killing a few thousand workers because that's essentially how their societies greet each other. It takes two lopsided wars (that humanity barely survives) before either species figures out the misunderstanding (though they still have no idea how to actually talk to each other). The Buggers are deeply aghast at the number of unique individual humans they killed in the wars, and thus fairly resigned to their fate when humanity retaliates by pushing the Buggers to the brink of extinction.
- The Gonne invokes this trope, killing off people who might be able to replicate it. "One of a kind is special."
- In the Beautiful Creatures series, there's John Breed, who is half incubus and caster. That is, he is an incubus who can go out in the sunlight and can absorb and keep the powers of other casters through touch. He was specifically bred by the villains to create a new 'super breed' to wipe out the casters and become the most powerful in the world. So, everyone is trying to figure out who his parents are, what all his powers are, and what his true significance is.
- The companion book to Penn & Teller's Cruel Tricks for Dear Friends includes a short story in which aliens land on Earth and their hat turns out to be valuing uniqueness. Unfortunately, it turns out that Humans Are Special is averted: everything about us genetically, biologically, and culturally is reproduced somewhere else in the galaxy, and we're slated to be forcibly removed to clear up space for a more unique species to inhabit Earth. The only thing that saves us is a magic trick. The ending is left slightly ambiguous about whether or not the aliens were actually fooled by it, but the implication is that we're the only species to have made an art form out of using sleight of hand to fool one another for entertainment purposes.
- In Acorna Series Acorna - The Unicorn Girl, Acorna was coveted by Hafiz, a collector all things rare and unique. And he was prepared to kidnap her from her three adoptive "uncles" (one of whom was Hafiz's own nephew and heir, Rafiz). He loses said desire when it's discovered that Acorna wasn't a singular specimen, but a member of an alien race.
- In Pact, the sorcerer Johannes Lillegard controls a number of vestiges, essentially copies of real people that he's made using his magic. He sells their suffering to supernatural creatures in exchange for power, and doesn't see anything wrong with this because they're not really people, they just have the exact emotional reaction to being tormented that the original would have. Maggie Holt, a viewpoint character, is repulsed by this idea, as she has several people she considers very close friends who don't even fit that criteria.
- Redwall combines this with Conservation of Ninjutsu, as the leader of a vermin horde will often have less of that type of vermin in it, and those that are are often Elite Mooks or Court Mage, especially foxes (except rats). Taken even further with the Seldom-Seen Species like pine martens and wolverines.
- In the first novel of the Artamon's Tears trilogy, Gavril is at one point coerced into consuming, over a period of time, a potion that will first weaken and then destroy the drakhaoul he has bonded with. The daemon's pleading to Gavril that "you're killing me... and I'm the last of my kind... the last in the world..." is surprisingly moving, given that we know by that point how monstrous it is. Of course, it helps that Gavril is The Hero and the drakhaoul, however unpleasant, is his only means of protecting his country from The Empire.
- Journey to Chaos: Kaiba Gunrai seeks out the unique all the time and spends much in the way of time and money in this pursuit. It's part of his eternal hobby. Except, he hates unique things. Unique things can't be mass produced and commoditized and thus they represent something outside of his sphere of influence. He seeks unique things so that he can copy them and thus strip them of their unique status. This is why he seeks out Annala, who has been Touched by Vorlons and thus unique in all of creation.
- Once Cylons in Battlestar Galactica lost the ability to resurrect, killing them got a lot more meaningful. Also, the Final Five are individuals, designed most of the Cylon tech, and know the way to Earth, making them some of the most unique and valuable people in existence.
- Taelons in Earth: Final Conflict have been unable to reproduce biologically for centuries now, and had their homeworld destroyed by the Jaridians, making the death of any Taelon a heavy blow for them as a species.
- Doctor Who:
- The Doctor is the last Time Lord (Sometimes). Oddly enough the Doctor is probably the least powerful of his race, as he uses a TARDIS that was old when he will first stole it a hundreds of years ago, and a few other assorted trinkets. Considering the Time Lords provide the page quote for Abusing the Kardashev Scale for Fun and Profit, he's positively roughing it. He's probably smarter than the rest of his people though, and he was already unique by being willing to do something about all the evil in the universe, rather than just watch.
- The various alien species who are in genuinely desperate straits, but whose plan to save their species inevitably requires human deaths may invoke this trope. For example, in "The Vampires Of Venice", the monster of the week needs to destroy Renaissance Venice to save her people. The fact that the Doctor inevitably chooses to doom a sapient species to extinction rather than sacrifice a relatively small number of humans is commented on as evidence of his favouritism towards humanity (rather then, say, stopping an Evil Plan).
- There's usually at least one character like this in the main cast of each Star Trek series:
- Data on The Next Generation. While he does find a handful of other robots like him, such as his Evil Twin Lore, they tend to get destroyed or are otherwise incapacitated so that by the end of the day, there's only one left.
- For Star Trek: Voyager, There are two characters who fit this: Seven of Nine, for a while the sole Liberated Borg, who gets specifically chased down by the Borg Queen because of her uniqueness, and the Doctor, the only hologram who develops his own unique personality. It's little wonder they became the Spotlight-Stealing Squad.
- John Crichton of Farscape. As of the final episodes of season one, this is why all the bad guys are always after him.
John: Why don't you leave me alone Scorpy?
Scorpius: Because the wormhole technology locked in your brain makes you, to my knowledge, unique in the galaxy.
John: (muttering under his breath) Unique.
Scorpius: And unique, is always valuable.
- Wander's goal in Shadow of the Colossus is to destroy all the colossi in order to resurrect Mono. However the more you play the game, the more you feel like destroying these ancient and unique creatures is too high a price to save one random girl. Especially those colossi who ignore you until provoked, or don't even fight back as you attack them; you end up feeling guilty every time you send another giant beast collapsing in slow motion.
- Explored in Planescape: Torment when you discuss the modron race with Grace. When a modron is destroyed, its essence returns to Mechanus, and a new modron of the same type is spawned. Since all modrons of a given type are identical, slaying one amount to nothing. However Nordom, a recruitable party member, has gone rogue and developed his own personality and individuality. If he is destroyed, his essence will also return to Mechanus, but the replacement will be a standard modron - not Nordom. The Nameless One even points it out - by going rogue, Nordom has effectively become mortal, since his death would be considered a loss. (This is, incidentally, why in the regular Planescape setting modrons make such a big deal out of hunting down rogue modrons - they are effectively stealing vital Mechanus essence for non-Mechanus purposes.)
- Runescape has certain items known as Rares, which are items that were given away for free years ago, or were freely/cheaply available - and they include things like paper partyhats, christmas crackers, easter eggs, and half-full jugs of wine. They include the most expensive items in the game and are useless - except for the wearable ones which offer aesthetic value only. Wearable rares are more valuable than non-wearable rares, but you still get things like the half-full jugs of wine being worth hundreds of millions of gold pieces purely from their rarity.
- You may find an intelligent (and very friendly) Troll in Age of Wonders - Shadow Magic who invokes this trope to reason that the hero should let him live instead of slaying him and making off with his hoard of gold.
- Mass Effect: After Shepard's squad kills a unique, 10,000-year-old creature known as the Thorian, an asari named Shiala briefly expresses some regret that this was necessary, and so does the Council. Why? Because the Thorian was the only one of its kind, and it was such a shame that the universe will never see its kind again.
- In Mass Effect 3 this is also noted with EDI, as the only AI of her type.
- Jade Empire: This is why Kang the Mad desn't want his Marvelous Dragonfly mass-produced. If there's only one of its kind, it will be the greatest flying craft ever. If there are hundreds just like it, it'll be plain and average. Kang also believes that another invention of his won't work properly until he's named it, so he's rather eccentric... but also correct. Then again, he is a god of inventions.
- In The Inexplicable Adventures of Bob!, Molly is protected by the Endangered Species Act because she's the only one of her species in existence. Since Galatea's birth, there are actually two, three, counting the giant baby Voluptua took away, but that still ain't very many.
- In The Wotch, the Unicarn demon is the last of its kind, because as a child, it wiped out the rest of its people. As a child. When he grew up, he REALLY started to regret that...
- In El Goonish Shive, Seers are a type of wizard so rare there is only 1 of them for every 7 million humans. Even rarer are seers who have used magic of which there are only five total on the planet. Of those five, three of them get the privilege of speaking to the Will of Magic itself.
- Storm Hawks has one episode devoted to helping a clutch of dragon hatchlings from being killed/captured by pirates, after dragons had been made all but extinct.
- On at least one occasion, Superman has been abducted by a collector of endangered species for being the Last of His Kind.
- Same deal for Danny in Danny Phantom where Skulker wanted to collect him because of his rare half-ghost status. Though after numerous failures to capture him, Skulker decided to just kill and pelt him instead.
- Sam was kidnapped by an egotistical ghost prince who wanted the novelty of having a human for a wife. How to pick the right one for the job? Hold a beauty contest at the Ghost Boy's high school.
- Parodied in an episode of The Simpsons when Marge and the Pre-Teen Braves are surprised to meet a Mohican.
Bart: Mohican? I thought you guys were all gone.
Mohican: No, but we encourage the myth. Chicks really dig you when you're the last of something.
- In Steven Universe, the Gems' Fantastic Caste System appears to at least partially run on this. Rarer Gem-types—such as Sapphires—rank higher than more common Gem-types—such as Rubies and Pearls. Ranking above them all are the Diamonds—of which only four are known to have existed.
- Fortunately, this is why we're so big on protecting endangered species. Tragically, the flip side of this trope is why it's hard to get anyone worked up about a species being over-hunted until there's only a few left.
- Handicrafts get part of their value from being from the minor imperfections that come from being handmade, and are considered to be more valuable than machine-produced products even if the latter usually have superior tolerances.
- Naturally-formed diamonds more valuable in jewellery than synthetic ones owing in part to the tiny little imperfections in them that simply can't be replicated artificially. Corrupt jewelers have even been caught swapping natural diamonds of jewellery they've been commissioned to repair or clean with identical artificial ones to make a little extra profit on the side.
- The Memetic line "Just because you are unique doesn't mean you are useful" coldly subverts this. It's typically written on images of things like a single misshapen fork or screw among some normal useful ones, an axe with a wooden head, or a watering can with the spout aimed back at itself.