Survival of the fittest - I'm sure you heard it in biology class. It's a sound theory, maybe even necessary. But sometimes, nature doesn't always favor us, or maybe another nation has it in for us. If someone manages to escape their fate, becoming the sole survivor, they will become bound by a greater calling than all of their supporting characters combined.
The Last of Their Kind - A character who is the only existing entity of their species, race, culture, or faith, caused by a great catastrophe, evolution, or genocide.
Avatar: The Last Airbender (pictured above) is a most recognizable series to demonstrate this trope. Not only is Aang the only person capable of controlling air, but he's the next in a line of Avatars, sentient guardians who control all elements. Double stakes; if he dies, so does airbending, and the baddies take over the world!
To be honest, this trope happens to guys all the time!
Err ... with exceptions, of course ...
This role is not limited to humans. Freaky humanoid-looking characters (or otherwise) can work just fine.
And people think Motion Capture is creepy
Some characters become the last of their kind simply because no one bothered to check the hyperspace routes in the planning offices of Alpha Centauri.
"You have a lovely towel ..."
In the famous The Dark Tower series, Roland Deschain isn't the last human around, but the last gunslinger.
"Feeling lucky, Crimson King?"
On rare occasions, humans are the perpetrators of annihilation, laying waist to alien civilizations across the galaxy. It's a good thing that not all human beings are heartless jerks. Take Ender Wiggin, for example. Take a big guess at what "last" character he's vowed to protect?
The Last of Their Kind is widely predominate in fiction literature and film, even though real life occurrences of this has and is happening in our world, right now (endangered plants and animals, for the most part). With the aid of friends and mentors, the most unlikely of survivors may right the wrongs of the world and begin anew - if anyone's willing to hook up.
Do you have a The Last of Their Kind character in your writings? What other examples can you name?
I'm David, and there is ... another ... Sky ... walker ...
(Skip to 4:10, if you'd like)