The Hero is obviously not qualified for choosing the fate of mankind, at least by traditional standards, but the Powers That Be have a good reason to trust him. Maybe he's The Chosen One who is predestined to have the correct choice, the Ridiculously Average Guy who somehow represents all of humanity's opinions, or maybe, a more personal Powers That Be simply finds him sympathetic.
So The Hero has to use his best intuition, and make a choice that will influence everything.
This whole situation is closer to the idealistic side of the scale, so usually the protagonist's choice will also be the more daring, fantastic, and optimistic option.
"End of the World" Special is an extreme version of this trope.
- In The Disappearance of Haruhi Suzumiya, Nagato Yuki obtains a power that can completely rewrite the world, and she asks Kyon if she should use it or not.
- Rei to Shinji in End of Evangelion, and this being Evangelion, Shinji takes the Omnicidal Maniac route, jump-starting Instrumentality.
- In Planet Ladder, The Ditz main character is responsible for deciding the survival of planets. Towards the beginning, her mentor tries futilely to pound that into her bubbly head.
- In Scrapped Princess, the sufficiently advanced god-program-thing, Mauser, asked Pacifica if it was really such a good idea to trap mankind in Medieval Stasis, because she started to doubt in it herself.
- The point of Future Diary. However this God selects some deeply mentally deranged individuals, and seems to want the fun of watching them kill each other more than anything.
- In Lucifer, God, after exiting his creation without warning (thereby bringing about its slow decay), has Elaine Belloc and Lilith (both of whom started out human) plead their cases for and against preserving the cosmos.
- In PS238, the Powers That Be, with the time-traveler Tom acting as its agent, needs to decide whether humans should continue to gain Metahuman Powers, or if superpowers should gradually fade and disappear into myth - until next time the choice has to be made. But Tom isn't the one who'll make the choice - he merely chooses WHO gets to choose, and he picks Tyler Marlocke, the only normal boy in the 'School for Metaprodigies'. In the end, while he gets to summon various acquaintances to get their opinion of the issue, it's up to Tyler to decide whether superpowers should continue to exist. This has happened many times in the past, explaining why myths and legends are so full of impossible magic and heroes. Spell Syrin is from one of those older eras.
Spell Syrin: Some of us knew this age of magic would end, and we wanted to see what came next. We used powerful spells to preserve us. A few left as new heroic ages arose, but I wanted for the final age, when humans would hold onto their strange powers for all time.
Tyler: Oh. Sorry to make you wait so long.
Spell Syrin: I beg your pardon?
- President Bill is about a man named Bill who was picked at random to be the President of the United States.
- The Neverending Story: Fantasia is a world inside a book that is borne from the hopes and imaginations of human beings. Unfortunately, in the "real" world, people have begun to lose hope and imagination has begun to run dry, and thus Fantasia is being destroyed by "The Nothing". The only thing that can save Fantasia is an Earthling child...who is revealed to be Bastion, the boy reading the book. As Fantasia is consumed by the Nothing, the Childlike Empress pleads with him to give her a name as the only way to save her world. Unfortunately, Bastion is too late, until only one single grain of sand is all that's left of Fantasia. Fortunately, since Bastion is still there, the Empress tells him that all he needs to do is start making wishes, and the more wishes he makes, the more beautiful Fantasia will be reborn.
- The 2008 film Swing Vote is about a U.S. presidential election that comes down to a lone man's vote, and the candidates' attempts to win his support.
- In The Belgariad, an ancient cataclysm split the mind of the universe itself into two opposed Sentient Cosmic Forces of Prophecy that wage a proxy war of Chosen Ones across history, up until the penultimate Chosen Ones appoint their successors and a human mediator makes the final Choice of victor. The Time Abyss sorcerer Belgarath speculates that the planet itself was created just to give the protagonists something to stand on while they fix things.
- The Isaac Asimov short story, Franchise, where elections were done, not by asking everyone one question ("who are you voting for?"), but by asking one person a whole bunch of questions (mostly unrelated to the election itself) then inputting all the answers into a computer and calculating the election results from it. Apparently the computer was so powerful that it could extrapolate national trends from a single person, but it needed that one "everyman"'s opinions to base its calculations on.
- In Foundation's Edge, the protagonist had to choose between a Galactic Empire, a different Galactic Empire ruled by Telepathic Spacemen, or Assimilation. He was chosen because he was statistically proven to be the luckiest person in the Galaxy. While the Assimilation option could have been forced on humanity by the Hive Mind planet regardless of this choice, that planet is bound by an altered version of the Three Laws of Robotics, which they interpret as forbidding them from forcing Assimilation on the rest of humanity without an unbiased human's permission. However, the prequel Foundations Triumph throws this into question when Hari Seldon deduces that R. Daneel Olivaw will hand-pick the most lucky man to avert a robot civil war.
- The Night's Dawn Trilogy ends in this way, with the hero being granted the power of a "Machine God" to solve the problems.
- Oathbringer (third book of The Stormlight Archive): Dalinar Kholin's spiritual bond to the Stormfather, a primal spirit that is a fragment of the dead god Honor, grants him the authority to set the rogue god and Greater-Scope Villain Odium free from its prison. Since Odium had already scarred several planets by murdering its way through the pantheon and would do the same to his homeworld, Dalinar is very careful not to do this — but they both know it's an option.
Odium: Is that an offer to release me from my bonds, coming from the man holding the remnants of Honor's name and power?Dalinar: [beat] No.Odium: Ah, all right then.
- In So Long, and Thanks for All the Fish, it turns out that the real President of the Galaxy is a little old man in a shed in the middle of nowhere. All he's interested in is feeding his cat, but occasionally people stop round and ask him what he thinks about certain things.
- The Ravirn series has the title protagonist in a position to influence the future of his Multiverse (as normally run by Necessity): due to a spell/"computer virus", the connections that kept the Multiverse together frayed, and he's considered the best option to put it back together. So who gets the be n charge now: Zeus, Hades, Discord, or the three Fates?
- There are several examples in Greek Mythology. Typically, there's a Sore Loser and a Curse, with the standard moral "smart mortals don't get involved with godly disputes."
- King Midas was asked to judge the music competition between Apollo and Pan. An angry Apollo gives him the ears of an ass when he rules for Pan.
- Tiresias was asked by Zeus and Hera to judge whether the man or the woman receives more pleasure from sex, as he'd been both. He chose women, and Hera struck him blind, for which Zeus compensated him by giving him prophetic powers.
- The Athenians were asked to choose a patron god by judging a contest of boons between Athena and Poseidon. The chose Athena's olive tree over Poseidon' saltwater spring, hence the city's name.
- Paris was chosen to select the most beautiful goddess among Hera, Athena, and Aphrodite. We all know how well that ended.
- In Ben Croshaw's homemade adventure game "Adventures In The Galaxy Of Fantabulous Wonderment" this happens at the end when the Powers That Be, actually the spirits of everyone who ever died, ask the hero to choose whether they should raise everyone to the same state of existence as them and explore other universes, or whether they should just let humanity develop on its own.
- Golden Sun: There was one of these in the Back Story. Alchemy was so destructive that the ancient civilizations sealed it away, leaving only a bare trickle of it behind. Unfortunately, millennia later it's discovered that the world needs alchemy; without it, the land is shrinking, and the edge of the world wearing away. The heroes have to unseal alchemy to save the world, and hope that things don't go too haywire.
- Legion's loyalty mission in Mass Effect 2 revolves around this. The geth, a race of robots, have split into two groups - the main group just wants to be left alone to evolve and learn. A smaller group (aka 'the heretics') have taken up a deal with a race of Eldritch Abominations to recieve great power by becoming slaves. The main geth have a virus that can rewrite the heretics to conform to the main group's point of view - effectively brainwashing them - and give them the desire to return home. The moral conundrum is whether to brainwash the heretics, or simply destroy them. Legion, your orthodox geth teammate, can't decide - their Mind Hive is in an almost exact deadlock. They trust Shepard to make the decision for them, since they've fought the heretics personally and have a unique perspective.
- In Mass Effect 3, the Catalyst offers Shepard several choices to end the Reaper cycle: control the Reapers, destroy them and every other synthetic in the galaxy or, if your assets are high enough, Synthesis, which involves changing the relations between synthetics and organics forever. The Catalyst acknowledges that by creating the Crucible and reaching it, Shepard has shown that the previous cycle was a flawed solution at best.
- This is how the world is supposed to work in Shin Megami Tensei III: Nocturne. Humans with strong Reasons (principles, really) fights each others and the victor ascend to Kagutsuchi, which then remake the world according to the Human's wish. But then Lucifer had to come around and screwing the system by creating the Demi-Fiend (you, that is).
- Xenoblade: At its climax, Alvis gives Shulk the chance to become the god of the new world, but Shulk turns the offer down, reasoning that it's better to live without gods deciding peoples' fate, and to let everyone decide their own future.
- El Goonish Shive: Magic is a Sentient Cosmic Force that wants to be used, but not by everyone. If too many people figure out how to use magic, a council of seers will be called. Seers are extremely rare, and only seers who have used magic but don't know about the council can be a part of the council; the average is less than one seer per council. The seers then must present their case to magic with firm logic and convince it of what major changes should be made to prevent magic from being mainstream, or to allow it to just change slightly to accommodate the reveal. Either way, every seer in the world (one in seven million, so about a thousand total) will become aware of the changes and the reason behind them. The problem is that magic doesn't really understand humanity, so it's difficult to convince it of anything. After a few initial missteps, Tedd manages to dramatically and bombastically explain that keeping a masquerade is simply not an option; with modern technology, anyone can share the secrets of magic in a second. There's no way they can keep a thousand seers quiet. Magic agrees, and the reveal becomes permanent.