During the course of a Story Arc, your characters can go places, have adventures, fight bad guys, and right wrongs. They've loved and lost and learned...and then something happens. Something that they never expected. The bad guys win. The people turn against them. The Herodies.
And they don't have time to mourn or plan or get over their losses, because more bad things are happening. This is the point in a narrative when there's no hope, when the characters are at the edge of the Despair Event Horizon. It is frequently invoked for the strongest testing of The Hero's character: What You Are in the Dark.
Older Than Dirt, going back to The Epic of Gilgamesh. As an ancient and ubiquitous plot device, this scenario has received quite a bit of attention in literary circles; it's cognate to the "death" stage (preceding the "descent into the underworld", but not always clearly distinguished from it) in certain formulations of The Hero's Journey monomyth, and shows up elsewhere as well. At least one creative writing course views such "black moments" as essential to effective plotting.
This usually precedes a Day of Reckoningclimax where only a few things can happen:
Dragon Ball: Piccolo Daimao had killed Goku's best friend Kuririn, with him failing to avenge him, now his Old Master Muten Roshi is also dead along with Chaotzu, Piccolo got his wish for eternal youth, and worst of all, he killed Shenlong himself so that he is no longer challenged.
During the Chapter Black where the whole objective is to prevent a portal to the Demon Word from opening potentially letting in A and S Class Demons that can potentially wipe out the Earth. Also the Black and White Morality the heroes are so used to gets thrown out the window. Made even worse that even the protagonist of the series could not catch up.
Sensui's power far exceeded Yusuke's, being an S class while Yusuke was a B+ at best. Knowing he had no chance of ever beating Sensui, Yusuke opted for a Heroic Sacrifice, letting Sensui kill him, thus boosting the the power levels of Kuwabara, Kurama, and Hiei up to A class. 3 A Class fighters against an S Class was still a very one sided Curb-Stomp Battle in favor of Sensui. It took two Deus ex Machina just to beat him.
Sakura Wars: the Movie: Commander Yoneda is missing, Orihime Soletta has been ambushed and brainwashed by Patrick Hamilton, Maria is missing after attempting to investigate Douglas-Stewart, and the Imperial Flower Combat division has been placed on indefinite standby and isn't allowed back at the Imperial Theater.
At the end of season one of Tower of God, this happens for both Baam and his team in different ways. Baam is betrayed by Rachel, debasing everything he worked for until now, because all he wanted was to be with her, which also destroyed a large part of his trusting nature, and for the team… well, the one that held it together died. Rak and Androssi didn't even bother to show up for the announcement of death, but they all decided to help Rachel achieving her goals to cherish Baam's memory.
Mazinger Z: Its Darkest Hour happened in episode 92, but the Mazinger vs Great General of Darkness expanded upon it and turned it even more tragic: The army of Mykene Empire struck, easily razing several big cities (Londo, New York, Moscow...) to ruins. When they raided Tokyo, Kouji flew to fight them... and got the crap beaten out of him. When he returned to the Institute, he found out several Mykene Beasts had smashed the place, destroying Sayaka and Boss's Humongous Mecha. And Shiro, his little brother, had been hurt when a ceiling collapsed, and he urgently needed a blood transfusion. In spite of he was weak -and he was underage- Kouji DID demand they used his blood. Later, at the night, he was sitting in what was left of his bedroom, observing a picture of his father and his grandfather and crying Manly Tears as he muttered the Mykene Beasts would return, and he could not win, but he would fight even though he knew he was going to die (unbeknownst to him, sayaka was observing him, shedding tears as she heard him talking).
Great Mazinger: In the anime it happened in the last episode: the Mykene bombarded the Fortress of Science, Kouji and Tetsuya were forced to fight separately, Tetsuya was defeated and nearly got killed and Prof. Kenzo Kabuto died. And in the Gosaku Ota episodes it was worse.
Nevertheless, in that same manga the Darkest Hour happened in one of the last arcs: Great Marshall of Hell blackmailed the Government into destroying the Fortress of Science, Great Mazinger and Venus A. The Fortress was blown up to bits and crumbled into the ocean, the heroes were forced to flee and hiding, and while they were seeking a shelter and lying low, the Mykene army conquered Japan.
By the last episode of Scrapped Princess, Pacifica has sustained a mortal wound, Prince Forsythe has given himself a mortal wound, Shannon and Zefiris have been dragged off by the surviving Peacemakers, and for good measure, the Royal Forces start blasting the place. It ends well.
Macross Frontier's Darkest Hour begins around episode 20, with the president being assassinated, a Vajra infestation on the main ship causing wholesale civilian slaughter, the death of Michel as he defended his love, and the departure of Ranka Lee. Things go From Bad to Worse ... but eventually end well.
The Darkest Hour in Digimon Tamers is when the children realize they can't beat the D-Reaper even with All Your Powers Combined, Juri is in a suicidal, catatonic state, they learn that the D-Reaper obliterated the Digital World, making it a Barren Wasteland, and they realize it's plan to cause a Class 6 Apocalypse.
In Code Geass, the Darkest Hour for Lelouch comes in R2 episode 19. He doesn't take the news of Nunnally's death well. Unfortunately, by episode's end, with the Black Knights betraying him and Rolo dying to save him, he has passed the Despair Event Horizon. This leads to some regrettabledecisions.
It's not what Lelouch regrets... it's what everyone else regrets. For Lelouch, Nunnally's apparent death is his darkest hour... but for Nunnally and all Lelouch's friends and loved ones, the "Darkest Hour" of his apparent descent into evil is quickly topped by the Darkest Hour that comes from realising that he just wants to die, has planned to do so all along, and there's nothing they can do about it but watch him bleed to death. And that's not even getting into opinions about how much of a purpose Lelouch's Thanatos Gambit might have served, and whether his opinion can be trusted, given his and his parent's poor track record in regards to such plans.
In the manga, Rosette is nearly killed when Chrono goes into an Unstoppable Rage. Chrono realizes what he's doing in time to save her life, but Aion uses it as his chance to incapacitate him. Azmaria is then kidnapped, Aion leaves the rest badly injured, and Chrono is so distraught that he forces himself into an Angst Coma so he won't take any more of Rosette's lifespan. It ends once Rosette and Chrono decide to follow Aion to his base of operations.
In the anime, Rosette is kidnapped by Aion and brainwashed to take part in his plans. Chrono manages to free Joshua from the horns, but they've damaged his mind so much he barely remembers anyone, and in the process Chrono is frozen in time. Thing spiral out of control from there, and don't get better until Chrono's final fight with Aion, and the rest of the series is grim up until the ending.
In Princess Tutu, the Darkest Hour is when the Raven turns the townspeople into crows and captures Mytho when Princess Tutu can't remove her pendant from her neck (which is Mytho's last heart shard). Ahiru becomes so depressed that she believes the only way she can help everyone is by killing herself. Fakir stops her by convincing her that he will always be with her and they can save Mytho together. The Darkest Hour comes to an end when Ahiru finds the courage to give Mytho the pendant and return to being a duck.
Naruto: During the Pain Invasion. The village has been leveled, with several important characters and hundreds of nameless villagers killed. Naruto's sudden badassery has failed and he is pinned to the ground helpless. Worse still, he can find no response to Pain's nihilistic Breaking Speech. Then Hinata tries to come to his aid, makes an Anguished Declaration of Love and attacks Pain, only to get stabbed. Naruto's shock and anger overcome his protective seals and the power of the Nine-Tailed Fox bursts free like it has never done before. As a berserk Naruto is fighting Pain, the scene switches to Yamato (the only person who can rein in the Nine-Tailed Fox when Naruto loses control), who's miles away. He looks down to his tattoo that shows how many tails Naruto has unleashed (if all of them are released, the Nine-Tailed Fox can break free completely), and sees the number changing from 8 to 9...
In Cardcaptor Sakura, the main one comes when Sakura believes she's lost to Yue; she has a lucid dream in which the catastrophe takes place, and friendships no longer exist for the people Sakura was close to.
In Pluto, when all of the seven great robots of the world have been destroyed. Except for Atom, who may be insane at that point.
20th Century Boys' darkest hour is at the end of the second arc, which sees an even crueller person donning the Friend mask, killing several million people, and molding the world in his own image, making all the protagonists work up till then all for nothing.]] After that, things start to eventually look up, starting with the return of the supposedly dead hero from the first third of the story.
HUGE one in Fullmetal Alchemist: Father's just activated his transmutation circle and absorbed the entirety of Amestris. Then he absorbed the Truth.
The Elric brothers' first meeting with Father and the aftermath. They've found out the horrible secret of their country and they're led to believe there's nothing they can do to stop it. One of the chapters in this arc is even called "Inside the Belly."
The climax of Sailor Moon Stars. Sailor Moon and the Starlights are the only Sailor Soldiers left. This is on top of the dark shadow of Tuxedo Mask's disappearance that's been hanging around for half the season. The Hope Spot is a dream as well, and really not that close to the end.
Negima!'s Darkest Hour is everything that happens after the Governor's ball, most of it to Negi. The Governor tries to kill him after Negi uncovers his real objective, all while his Superpowered Evil Side is threatening to consume him. His mentor is killed erased in front of him. The secret organisation headed by his nemesis is activating the plan to destroy the Magical World, which erased a lot of his students' new friends in the crossfire as they watched. Oh yeah, Mahora Academy might not survive either. His childhood friend Anya and Asuna are being held hostage, and he's just found out that the Asuna he's been with for all this time is a sleeper agent that he has to unmask. On top of this, he has to beat the evil side into submission, otherwise he'll turn into a feral, homicidal demon the next time he uses Magia Erebea. He feels personally responsible for most of these... and he's just ten. Most overwhelmed little boy since Ender Wiggin.
As if that wasn't enough, the final showdown between Ala Alba and Kosmo Entelechia has gone wrong. Horribly, horribly wrong. Negi is incapacitated (bad), so the rest of the team pull off a daring rescue (good). Half the attacking group is turned to stone in the clusterfuck (bad), but at least they've stopped the world-ending ritual and stolen the artifact, rescued the princess and saved the world, right? Uh, no.
Part 1 - The seemingly dead Dio attacks Johnathan on his honeymoon.
Part 2 - Cars achieves his goal of becoming an ultimate being and is now immune to Hamon, and Joseph's out of ideas.
Part 3 - Kakyoin, Iggy, Avdol, and Joseph are dead and just Jotaro remains to take on Dio and his almost invincible time stopping power.
Part 4 - Kira has gained a new Stand ability that allows him to easily pick off the only people who can stop him, and the only person who knows Kira's real identity has no way of telling them directly.
Part 5 - Polnareff's Requiem Stand has gone berserk, and thanks to some body-switching, Big Bad Diavolo is in Buccarati's body, Narancia is dead, and the Requiem Arrow is almost in Diavolo's hands.
Part 6 - Pucci upgrades his Stand to one that can reset the universe, and he plans to make a world where the Joestars never existed. The only one stopping him is a kid with no offensive abilities whatsoever.
Part 7 - Valentine has all the corpse parts and merges them with Lucy, giving him complete immunity to Johnny's attacks, Gyro's strongest attack doesn't work and gets him killed, and then Diego shows up...
One possible explanation is that it really is a reset, but only the wolves are reincarnated in it (Darcia did say that it was "a paradise only for wolves").
Out of 50 episodes in Eureka 7, episode 44 arguably takes the spot for this trope. The entire episode is a depression.
The last part of the manga Hellsing develops with the city of London destroyed by vampires and crusaders, with Alucard far away in a ship, and the Hellsing manor almost destroyed and under the attack of vampires. The situation doesn't get better until Alucard arrives (which actually makes things worse).
It gets much, much worse. The Vatican authorizes purging of London. Anderson becomes a thorn-monster-thing. Walter pulls a Face-Heel Turn. Alucard DIES and does not come back before the end of the war.
The Water Seven and Sabaody arcs in One Piece, both storylines in which the Straw Hat Pirates have come close to annihilation.
Those are tame compared to The Marineford arc. The marines succeed in executing Ace, Blackbeard kills Whitebeard and steals his powers, Luffy has sustained a massive amount of damage and sacrificed part of his lifespan in vain, and several villains from previous arcs have now been freed from prison (by Luffy himself, no less), and as the cherry on top, Luffy lost his brother despite all the sacrifices he made.
The end of Hong Gildong arc in Shin Angyo Onshi. The main character willingly traps himself in a Lotus-Eater Machine which he considered a Fate Worse Than Death betting on One In A Million Chance of breaking free versus certain death otherwise. His main companion is deceived into working for the Big Bad. Anti-Villain antagonists of the arc are mostly dead. The main character's former old friend remains undead in the thrall to the Big Bad, and is revealed to be unable to die or to break free unless his body is completely obliterated. The city that the protagonists protected in the arc is taken over by the Big Bad. The Big Bad decides to stop fooling around and get to the businness of taking over the world, revealing his vast true power and his array of superhuman henchmen. Few good guys still standing are being manipulated by him.
By episode 11 of Puella Magi Madoka Magica, Homura is the only magical girl left alive and is fighting a losing battle against Walpurgisnacht even after unloading a small army's worth of firepower on it. After repeating the same six weeks who knows how many times, she finally gives up hope... cue Wishplosion courtesy of her beloved Madoka.
Ichigo's lowest personal moment of the series is probably in chapter 459, during the Fullbringer Arc. All of Ichigo's Nakama are either fighting against him due to the Big Bad's More Than Mind Control or are critically injured, the guy who he thought was a friend turns out to be working with the big bad the entire time, the powers he worked to attain throughout the arc are taken from him, and after getting stabbed through the heart he finds his father behind him, seemingly the one who did it. He gets better.
And then things spiral down really hard for Soul Society and the Forces of Good(ish) in the beginning of the Thousand-Year Blood War Arc. Yes, you read that right, the beginning. The darkest moment is probably around chapter 510: Soul Society has been laid waste by the Vandenrëich, with casualties on the shinigami side mounting to the thousands in fifteen minutes of battle—and of the named characters Byakuya, Renji, Rukia, and Kira are all at least seriously wounded and possibly dead and Sasakibe and CAPTAIN-GENERAL YAMAMOTO HIMSELF are confirmed dead (yes, Old Man Genocide DIES); five bankais have been stolen by the enemy including Yamamoto's; even Zaraki's been curbstomped by Ywhach; Urahara, Orihime, and Chad are all waylaid in Hueco Mundo by the Quincy recruiting squad; Ichigo is trapped in a Garganta and unable to do anything from his prison but listen to the battle—including the screams of the wounded and dying and the Technology Division being destroyed...oh, and Aizen might be on his way back into the plot. For the first time in the history of this manga, it is unclear how many of the main characters will make it to the end.
Sango and Miroku waiting for the Wind Tunnel to absorb them while their despair consumes the light within the Shikon no Tama leaving it in darkness.
Sesshoumaru's darkest hour occurs when he finally learns the truth about Tenseiga's origins and the real reason why he was given Meidou Zangetsuha, resulting in him believing that his father had been training Inuyasha to kill him. His Heroic BSOD is so blatent that even Myouga is desperate to help him. He's left so shaken that when Naraku attacks his group he doesn't even try to rescue them; Inuyasha ends up saving them while he watches from a distance. Nothing in the manga - not even Kagura's death or Rin's second death - has ever made him despair the way thinking his father hated him did.
Inuyasha is tricked into thinking he murdered Kagome in his blood rage. This breaks him down so completely that he gives into his despair and demon blood.
High School D×D's Darkest Hour occurs in the 11th volume when Opfus had 75% of her powers drained from her. Then they're trapped in an alternate dimension surrounded by grim reapers. They were able to destroy the statues and were already about to get out of that place when Opfus gets kidnapped by a newly-rebuilt Shalba Beelzebub, and Ise has to rescue her. The volume ends with Ise getting hit with a dragon-eater Samael blood coated on an arrow, leaving him to die in that place. That's not all however; Hades starts a war on the Underworld, Azazel's been accused of cooperating with terrorists even though he's the one who wanted peace in the first place, and every single member of the Occult Research Club suffering a Heroic BSOD.
Mobile Suit Gundam SEED, the Darkest Hour is when the nuclear armed Blue Cosmos is ready to nuke the PLANTs with over a hundred nukes, and ZAFT is ready to use their Wave Motion Gun on Blue Cosmos and Earth, and the Three Ship Alliance in between trying to prevent both sides from wiping out each other.
While Popotan isn't exactly a dark series to begin with, it does reach a very bleak point in episode 11. The main characters have been told that they can either continue time travelling with all the impediments that would put on their social lives, or live away from each other in three separate time periods; after Mai leaves, Ai and Mii find going on to be pointless and eventually abandon their journey too. The next episode reveals that none of them are very happy about the situation.
Power Stomach/Belly Buster in the episode "A Half-Baked Battle" has just caught Kirby, Dedede, and Escargo(o)n in its grasp and swallowed all three and is proceeding to digest their limo, with all three being next. Cue Dedede whipping out a bomb for Kirby to suck up and blow the monster up from within with.
Kirby getting pulverized by Masher in the second Knuckle Joe episode, "Monster Management," to the point of not being able to even stand anymore. It goes From Bad to Worse when Knuckle Joe joins in the fight and tag-teams his attacks with Masher until they have him cornered. Tiff, with tears swelling up in her eyes, pleads for Joe to stop but he keeps going. Finally, deciding to finish off the pink spud, Joe uses Smash Punch and... tells Kirby to suck it up?! Which he does, and becomes Fighter Kirby, and then they start mashing Masher?! Wow.
In the first New Year's episode, "Cappy New Year," after Fire Kirby barely succeeds in destroying Sasuke's Dedede float, he gets knocked out, losing his Fire ability in the process, which is just great as Sasuke uses a large firecracker to pin Kirby on top of it in a last-ditch effort to get rid of him. When Kirby starts moving along the firecracker's surface, Dedede launches several more firecrackers at them. Kirby sucks up Sasuke right before the firecracker explodes and seemingly takes him out with it... thank goodness it's revealed that he got off just in time and became Parasol Kirby to float down to everyone and celebrate the new year.
The Mumbies Kirby fought against in its own episode, "Mumbies Madness," gives him another one. After dodging several bombs from Bomb Kirby and being taken by surprise by more of them and barely dodging them, the Mumbies clamps onto Kirby with its teeth and is gnawing away on him, and all hope seems lost for the little spud... cue the sun rising and Kirby keeping it on him long enough for the sun to burn it to a crisp.
In episode "Dedede's Raw Deal," Kirby's getting pummeled and fried by the electricity-firing Squishy, and to make matters worse, he can't fight back because the sweet potato he ate before Squishy started attacking him is giving him hiccups which prevent him from sucking up attacks. Luckily, Tiff comes up with a way to scare him out of them just in time by telling him that he won't be able to eat again if he keeps up his constant hiccups.
In "Frog Wild," Dedede allows the Demon Frog that possessed Kirby to possess and buff him with the immense strength that he uses to beat Kirby to a pulp to the point of rendering him unable to even stand anymore, and then he's about to bring down his hammer... then Heavy Anaconda shows up, eats the Demon Frog, and then eats Dedede (he gets better later).
Quite possibly one of the most infamous Darkest Hours in the show happens early in the five-part series finale, in Part One of the two-part "Air-Ride-in-Style." Kirby and the Warp Star are getting bombarded by plasma bolts from a Destrayer that was sent to nuke King Dedede's castle. When Kirby gets distracted trying to save Tiff as the two get bombed by plasma bolts, one of them chips off a piece of the Warp Star sending them falling to their deaths. And just when the Warp Star barely saves them and takes them to Kabu, it gets worse as four Air Riders go after Kirby while the Warp Star is still regaining some of its strength... (which turned out to be All Just a Dream, of course.)
In the second-to-last part of the five-part series finale, "Combat Kirby," Heavy Lobster is rampaging around the Halberd, and is so far proving to be unstoppable. Not even Cook Kirby can stand up to the metal menace and when it reaches the engine room, it looks like nothing can stop it from destroying the main engine and bringing down the Halberd itself... until Kawasaki gives Kirby some ice cubes to eat so he can turn into Ice Kirby and freeze it enough for it to be blown to smithereens by Sword Knight's bazooka.
In the Grand Finale, "Fright to the Finish," Fire Kirby has used up all of his energy and reverted back to normal after tiring himself out trying to attack Nightmare physically. Nightmare then decides to enter his sleep and give him a nightmare by torturing him before moving on to crush him, and when he starts messing with Kirby's food, Tiff tries calling for the Warp Star, but it's nowhere to be found in Kirby's dream. Just when all hope seems lost for the pink puff, cue Tiff pulling out the star and giving it to him to eat up to become Star Rod Kirby, Nightmare's one Weaksauce Weakness.
In Berserk the Band of the Hawk's darkest hour comes after the completion of their Griffith rescue operation, which was the first victory for the Hawks since their downfall upon Griffith's imprisonment, but a Pyrrhic Victory at that, since Griffith now disfigured and crippled beyond repair after a year of torture can never wield a sword again and the Hawks can never return to their status without his leadership. Most of the Hawks are confused and emotionally distraught, especially Guts, Casca, and most of all Griffith himself. He goes through a Despair Event Horizon as a result, but during it, he finds a glimmer of hope for himself; unfortunately, it's a VERY BAD ONE for everyone else involved. It's made that much worse for watchers of the anime, where all of the above happens... and then the series ends.
In Heartcatch Pretty Cure, the girls end up confronting Big Bad Dune for the first time... and he easily hands them all their asses, kidnaps Tsubomi's grandmother, regains his full power, then proceeds to turn the Earth into a desert and it seems that, for a little while, those four are the only people alive...
And again with New Phyrexia. If you haven't gleaned how that's a Darkest Hour from the title, the Phyrexians have invaded another plane. This time, they've won. From what's been spoiled so far, it seems as if they've been able to infect mana itself. The multiverse is screwed.
The current page image takes place on the plane of Innistrad. The only thing keeping the humans of Innistrad from becoming lunch for the resident zombies, werewolves, vampires, ghosts and demons is faith in the archangel Avacyn. Or I should say kept. Avacyn has gone MIA and the wards and holy weapons are starting to fail, leaving them all but defenseless.
That block also gives us the Fateful Hour ability. Creatures and spells with this ability get a massive power boost when you're at 5 or less life.
Among other incidents, unprecedented amounts of crap hit the fan at the end of chapter 100 of Ultimate Spider-Man - right in the middle of the Ultimate Clone Saga. To whit: Peter has already found at least one violently insane clone of himself and has tangled with a mysterious Spider Woman; Mary Jane has been kidnapped by another warped and insane clone of Peter who intends to transform her to make her "just like him" (and as of the last page of the chapter has apparently succeeded); Nick Fury has shown up outside Peter's house to arrest him with an army of "Spider Slayers"; Gwen Stacey has mysteriously returned from the dead, but panics and transforms into Carnage (the monster that killed her in the first place) when Fury shows up; Peter was forced to tell Aunt May his secret when she discovered him with Gwen, driving her lash out at him for lying to her all along and telling him she doesn't want to have anything more to do with him, before the repeated shocks (Gwen transforming into Carnage being the straw that broke the camel's back) cause her to have a heart attack; and Peter's supposedly long-dead father Richard Parker has apparently shown up, with Peter shocked to realize that May had known about him for a while and had kept Richard's return a secret. That's a LOT of crap to be going down at once and it still has to get worse before it gets any better.
About midway through the Iron Dominion Saga, the Iron Queen hacks NICOLE, allowing the Dominion forces to seize control of New Mobotropolis and send the Freedom Fighters running.
The series seems to be heading into a new one, in the aftermath of the Genesis arc — not only has Eggman succeeded in roboticizing Sally and nearly killing Antoine, but rival villain Ixis Naugus has successfully manipulated the fear of the citizens of New Mobotropolis following the Iron Dominion occupation and subsequent events, allowing him to install himself as King.
Halfway through Knightfall Bane heads for Gotham City with the broken Batman and launches him into the ground below, crowds of people in total shock (except for one sleezehead who just sneers at him).
In With Strings Attached, the four return triumphantly with the third piece of the Vasyn, only to find the first two pieces missing and almost everything taken from the house. Tracking down their stuff, they end up in the ruined city of Ehndris, where they learn that Brox found a spell to restore monsters to Baravada—something they did not want to have happen. They're betrayed by their best Baravadan friend; John and Paul are kidnapped and put under the control of the baddies, while George and Ringo are neutralized and can do nothing to help. The Fans are nowhere to be found. And the topper is that Ringo is startled into teleporting hundreds of miles away, leaving George alone, surrounded by bloodthirsty revolutionaries, and utterly powerless.
Clash of the Elements: The end of Chapter 49 of Part 1. All the heroes are down for the count, Rosalina has fallen after proving unable to deal with Joe Dark after he went into his Griffon Form, the Genesis Samurais are all dead, the Dark King managed to set up a widespread wave of destruction across the planet during his brief moment of possession, Alex Whiter has had his subconsciousness destroyed, and Joe Dark is just about ready to destroy the Origin Temple, unaware that his attack will actually annihilate the rest of the planet too...
Silent Sorrow, the final story in the Tamers Forever series. As it opens, Takato is already dying thanks to his Superpowered Evil Side overloading his body. Then, Shinjuku is invaded by a Digimon army led by Daemon, who is after the power of said evil side and is so insanely powerful that the only way anyone can even think to foil him is to let Takato escape to the digital world — so he can die before Daemon gets him.
My Little Avengers: Chapter 14 and roughly the first third of chapter 15 — Loki'sDark Avengers have managed to defeat the Avengers, and a threat on Pinkie Pie's life gets Big Macintosh to surrender Mjolnir and Thor's power to Loki, who proceeds to pervert the Power of Friendship to strip the other Avengers of their powers as well. The Dark Avengers then assault the royal palace, banishing Luna to the moon and taking a depowered Celestia prisoner, with Loki proclaiming himself the new ruler of Equestria. Fortunately, Big Mac gets a Rousing Speech from a ponified Stan Lee, and he proceeds to do the same to his teammates, using the realPower of Friendship to restore their powers. They then take the fight to Loki, setting the stage for the Final Battle.
The 15th chapter of a different Cross Over fanfic, Ace Combat: The Equestrian War certainly fits. The griffins manage to seize Canterlot and the castle becomes the only save area. Many ponies were injured during their raid, some died. Tornado Swirl and Overdrive lost every one of their wingmates, the Stingray squadron was wiped out completely, Blueberry died a Cruel and Unusual Death and Carrot Top dies in Derpy's arms, much to her despair. The situation is so crushing that even Cloud Kicker bursts into tears!
Inner Demons: The prophecy refers to the Queen of Darkness' reign as "Equestria's darkest hour". That said, there are two moments that possibly qualify:
Relatively early on, when Twilight succumbs to the Darkness, crosses the Moral Event Horizon, and declares herself ruler of Equestria, before beginning a campaign to crush the rest of the Mane Six and any of their potential allies. It takes a long time for things to start to get better after this.
In Part 2, without enough time to prepare prior and while both mentally and physically exhausted, Phoenix struggles to keep standing against Trixie's firepower. This gets especially worse when in order to prevent the Judge from handing down an early guilty verdict on Rainbow Dash, he is forced to accuse Fluttershy of all ponies as a potential suspect, just to buy him more time. Not only is Phoenix visibly killing himself inside, he also alienates Twilight, risks losing his place as Rainbow's defense attorney, and Trixie continues to taunt him as she's winning all the same.
Queen of All Oni seems to have hit the Darkest Hour as of Chapter 14. Not only has Jade gone completely off the deep end and cut what few ties she had left to her humanity, but she's also forcibly transformed and brainwashed Viper into her new General, gaining control of the Samurai Khan and regaining control of the Ninja Khan at the same time. Uncle and Tohru, sensing all this, admit that the balance has shifted in evil's favor.
Film - Animated
During the animated Transformers movie. They even call it by name.
Ultra Magnus: "But Prime, I'm just a soldier... I'm not worthy."
Optimus Prime [mortally wounded]: "Nor was I. But one day... an Autobot shall rise from our ranks... and use the power of the Matrix... to light... our darkest hour."
How to Train Your Dragon has its time when Hiccup, disowned by his father after his forbidden friendship with Toothless the Dragon is discovered, watches the horizon helplessly after seeing his father's fleet proceed to the Dragon island with Toothless -and to certain doom when they are bound to arouse the Red Death Dragon.
Disney has a lot of these. Commonly they happen soon after the Award Bait Song or the runner up.
In Aladdin, Jafar gets the genie, becomes the most powerful sorcerer in the world, takes over Agrabah, turns Aladdin back into a street rat and blasts him to a far away snowy place.
In The Lion King, after Mufasa dies, Pride Rock falls under Scar's rule and Simba becomes too troubled over the guilt of his father's death.
In its sequel, Kovu gets banished from both Pride Rock and the outlanders.
Hercules has what is probably the best example on this page when Hades takes away Herc's power, unleashes the Titans and takes over Olympus.
The second one happens toward the end, when the Cy-bug horde has destroyed the entirety of Sugar Rush and are heading toward the tunnel to Game Central Station, Vanellope can't pass the gate due to her being a glitch, Calhoun runs out of ammo to fight the Cy-bugs, and Cy-bug!Turbo has captured Ralph when Ralph tries to activate Diet Cola Mountain.
Frozen: Elsa has accidentally frozen Anna's heart and only an act of true love can save her. Kristoff takes her back to the castle to be kissed by Prince Hans, who turns out to have been playing Anna for a sucker so he can kill Elsa, who had been captured and imprisoned, and take over Arendelle, leaving Anna to freeze to death.
In Kung Fu Panda, all the heroes have a soul crushingly heartrending night where Master Oogway, the only one who stopped Tai Lung before and the only one who has faith in Po as the Dragon Warrior, dies, leaving Master Shifu with a seemingly impossible promise to train the fat panda, while Po now fully realizes how hopeless he truly is, on top of his profound self-loathing that even Shifu cannot alleviate. Meanwhile, Tigress feels she has no other choice but to defy her master and set out to stop Tai Lung herself, despite his prohibition.
Both the first two Shrek films with both examples involving misunderstandings and Fiona hooking up with someone else.
Film - Live Action
In The Dark Knight, the Darkest Hour is when Rachel lies dead, Harvey's been disfigured and is out for revenge, and the Joker is holding two boats hostage, trying to prove that Humans Are Bastards and everyone is in despair.
Ironically, just before, Harvey had stated that "The night is darkest just before the dawn". If he only knew...
In The Dark Knight Rises, the Darkest Hour for both the movie and arguably the whole trilogy is when Batman lies broken and defeated and is imprisoned halfway around the world from Gotham City...which has been taken over by Bane. To make matters worse, Bane has made the city devolve into crime and chaos and is planning to nuke the entire city.
Serenity: The title ship is grounded on Mr. Universe's moon. Book is dead. Wash was killed by the Reavers. They've got one seriously ticked off Operative on their tail and the Reavers are descending upon the ship. Zoe even states outright that they're not getting out alive.
The Phantom Menace: Anakin's fighter gets stranded with no power in the heart of an enemy battleship, meanwhile Amidala's strike team is ambushed and captured, the Gungan army has been defeated and rounded up, and for the record: Qui Gon Jinn is killed by Darth Maul.
Attack of the Clones: The Jedi strike team sent to rescue Anakin and Obi Wan from Count Dooku is being overwhelmed by thousands of battle droids, Dooku then offers them a chance to surrender, which Mace Windu declines, so Dooku orders the attack to continue.
Revenge of the Sith: The Empire is born, Padme dies, Anakin becomes Darth Vader and the Jedi are exterminated (which sets up the conflict for the next 3 films).
Return of the Jedi: The Rebel fleet is being annihilated by the Death Star while their Ewok allies are being stomped by the Empire, R2 gets shot (again) and Luke has a brief lapse to the Dark Side and attempts to strike down both his father and the Emperor in anger.
Indiana Jones and the Temple of Doom: Indiana Jones is possessed by Mola Ram after being forced to drink the Blood of Kali, Willie Scott is about be sacrificed to Kali, and Short Round is enslaved by the Thugee Cult and is toiling in the mines being forced with the other children to find the Sankra Stones.
The Movie version of The Odyssey has one where all of Odysseus' men drown in a shipwreck and he washes ashore to Calypso's island where she makes him her sex slave for seven years. Homer's original is told Anachronic Order, so it's harder to pinpoint there.
In Pan's Labyrinth, when the Faun has forsaken Ofelia and her mother has died, leaving her all alone with her supremely evil stepfather.
First round in the first is when the Busters are eating Chinese takeout and Ray mentions that the business has just run out of money with that meal. That is exactly when the Sedgewick Hotel calls, desperate for their services; Janine at the front desk calls, "We got one!" as the enterprise is saved.
Second round in the first movie kicks off when Obstructive Bureaucrat Walter Peck ignores his expert's advice and has the containment unit shut down, causing the firehouse to explode and releasing all the ghosts that the title characters had caught to wreak havoc upon the city. Meanwhile Peck arrests the Ghostbusters for the explosion, taking them out of circulation and preventing them from rounding up the ghosts again.
The second film has the part when the river of slime comes up to the surface, covering the museum and generally causing havoc. Also counts as a literal Darkest Hour, as the influence of the slime causes an eclipse which plunges the city into darkness.
This occurs during the original Godzilla when Dr. Serizawa is torn between using the Oxygen Destroyer or keeping it a secret. It's not until he's shown the tragedy caused by Godzilla's rampage that he finally decides to use it...but only once.
The gay romance Latter Days, where we're led to believe closetted Mormon Aaron commits suicide after breaking up with Christian and getting excommunicated from his church for being gay.
In The Matrix Revolutions, Agent Smith escapes the Matrix and enters the real world in disguise and attacks the last of the human rebellion. He blinds a defenseless Neo who is really powerless outside of the Matrix, and becomes the biggest threat.
The Darkest Hour looks pretty bleak, what with cities crumbling and weird energy tentacles turning humans into ash. The perfect Christmas film!
The first time comes when the Helicarrier is barely functioning after the Brainwashed and Crazy Hawkeye's attack and the Hulk's rampage; Thor is gone, Banner is gone, Iron Man's armour is a hair's breath from completely crapping out, Black Widow is inches from a Heroic BSOD, Agent Coulson is dead, Loki has escaped, and S.H.I.E.L.D. still has no idea where the Tesseract is.
The Darkest Hour of the Final Battle is when the Avengers, despite having assembled, have been ridiculously outnumbered and outgunned by the Chitauri. Iron Man and Hawkeye are running low on ammo, Thor and Cap are surrounded, the Hulk is being pummelled by laser-fire, and to top it all off, the WSC declare "Screw it" and fire a nuke at Manhattan.
Frostbite: The police are surrounded by the growing horde of vampires and Annika has been turned into a vampire; the night is indeed darkest just before the dawn. The problem is that Frostbite takes place in the northern part of Sweden where the sun is absent for an entire month. Dawn is still several weeks away.
In Oz: The Great and Powerful, Oz, instead of leading the attack, tries to make a getaway, with gold — and Theodora shoots him down, leaving his balloon in flames.
Independence Day: "Negative. Target remains. I repeat, target remains."note This little quote comes after the President has made the painful decision to use the Nuclear Option, resulting in a deserted Houston being wiped off the map — only for the alien ship to emerge unscathed from the blast, revealing that its shields, and that of the other alien ships, can even withstand nuclear attack!
In Pacific Rim, the Kaiju have been increasing in strength and regularity. The Jaeger program, which was really the only effective way of dealing with the Kaiju, has been shut down in light of diminishing success. The Pacific Wall—the "viable alternative"—is quickly shown to be totally ineffective against the stronger Kaiju. And there are only four operational Jaegers left in existence.
In Tremors, the Gummers are the best armed and equipped people in Perfection, but a graboid has headed for their house, attracted to the vibrations of a brass cleaner and the couple moving around in their basement. Val tries to warn them over the radio, but Burt doesn't understand the threat until the graboid is almost upon them. The last thing Val hears on the radio is Burt's scream of surprise as the graboid breaks through the wall. A few seconds later, the sound of gunfire makes it to town. Cue the Gummers unleashing More Dakka on the graboid.
The Crossing starts at the American Revolution's darkest hour, namely winter 1776. The Continental Army has been completely thrashed, forced to retreat from every encounter, out of money, and if Washington can't come up with a winning battle plan before enlistments expire on December 31, the army will dissolve and the Revolution will be over. The end titles state that while the Revolution had many other low points, it never got this bad again.
In The Shawshank Redemption, it's hinted that Andy commits suicide, until...
In The Princess Bride (both the book and the movie), the boy gets a little upset at the part where Westley is dead and Buttercup supposedly marries Humperdinck. What's the point of reading this story? That's not how it's supposed to end! It takes him years to realize just how deeply that moment affected him.
Given the press of events (many of them bad news), these crop up fairly frequently in the Deryni works. A partial list:
Soon after King Brion's death, as he's troubled by vile rumours and worried about the Shadowed One, and having just been acquitted of treason and heresy, Alaric Morgan stands contemplating Brion's new tomb in Deryni Rsiing:
...That the good and gentle Brion should end this way was not fitting. Life had been too short; the good done well, but not enough done, for lack of tiem. Why? Why had it been necessary for him to end this way?
You were father and brother to me, Morgan thought dully. If only I had been at your side that day, I might have spared you this indignity, this useless gasping out of your life's breath! Now, with you gone...
Morgan again, late in Deryni Checkmate. He's barely escaped from men who wanted to burn him at the stake, his people are in revolt against him, the Church Militant has excommunicated him and his cousin (who's radiating his own misery over his threatened priestly vocation), his king and country are facing immenent invasion, his beloved sister Bronwyn and her fiance have died from a badly set love charm. He withdraws to the grotto on his castle grounds and overhears his bard weeping and composing a lament in honour of Bronwyn.
Duncan has one that begins in Dhassa, once he learns his father's army is missing; he stares out the window wracked by guilt over his duty to his father (Duncan is now the elder Duke Jared's only heir) and troubled by conflict between his priestly vocation ("at once held and not held") and his Deryni powers. Then one of his father's pages arrives on a foundering horse and collapses, and Morgan Reads the boy's memories to learn of Jared's betrayal at the hands of Bran Coris. Duncan doesn't entirely snap out of his funk until Richenda asks him to hear her confession two or three days later.
When Derry realizes the extent of Wencit's control over his mind in High Deryni, he tries to kill himself to avoid betraying Morgan and Kelson. His failure (caused by Wencit's implanted psychic compulsion) reduces him to weeping bitterly and stabbing the dirt floor of his cell with the dagger he cannot bring himself to use on himself.
Katie MacAlister's Aisling Gray series ends book three, "Light My Fire", at an incredibly low point.
In James Swallow's Warhammer 40,000Blood Angels novel Deus Sanguinius, Rafen first, under psychic attacks, nearly commits suicide. Fighting against the attacks, and a vision, free him from the compulsion but make his duty clear to him: he tries to blow up the city where his fellow Blood Angels are breaking with their Chapter. It fails, they pursue him. It ends only when they catch him in a factory, and it explodes.
The ending of Soul of the Fire sees Kahlan hanging to life by a fragile thread and having lost the child she was carrying, Richard believing that the Imperial Order is impossible to defeat, and a general lack of anything good having come from the events of the book, with Richard, Kahlan, and Cara quietly leaving in utter defeat.
In Andre Norton's Jargoon Pard, Kethan is Switched at Birth for a woman's daughter, because only a son can inherit. At the climax, this is revealed to the woman and his parents; they reveal that actually, they knew it for a long time, practically from infancy, and still consider her their daughter. Kethan nearly despairs, because his purported mother no longer wants him, because she can no longer use him. After the fight, however, his parents eagerly lay claim both to their biological son and the daughter they raised.
In Chapter 21 of The Pilo Family Circus, Shalice the fortune teller has gotten her crystal ball back, ending the Freedom Movement's attempt to destroy the circus and curtailing any future bids for freedom. For good measure, Kurt Pilo has had Winston tortured as negative reenforcement.
The Alienist: Dr. Kreitzler leaves the team after the shooting at his home. This almost derails the investigation.
In Warrior Cats, the darkest hour comes when Scourge kills Tigerstar, who had been the Big Bad up until then and declares that he and his clan are taking over the forest. Points for the book actually being called The Darkest Hour.
Queste: When Septimus is taken away from Jenna and Beetle in the House of Foryx.
Darke: After Jenna has told Septimus about Sarah being trapped in the Darke Domaine, he is completely broken.
Someone Else's War: Matteo and his friends have come up with a clever plan to arrest the ranking officials of the LRA without any violence. And then half his friends are wiped out in a single move when the LRA decides they've got too many mouths to feed.
Trapped on Draconica: After Yusef betrays the Eastern Alliance this trope occurs. The only remaining military threat to Baalaria is gone, Daniar is lethaly poisoned, Ben and Kalak captured, and all their possible allies refused or tapped. Then Rana shows up.
In The Riftwar Cycle by Raymond E. Feist, the most prominent one of these is the ending to A Crown Imperiled, with Pug, Magnus, Miranda and Nakor supposedly being dead, Drakin-Korin has returned, an angel has been killed by a strange creature and the Kingdom of the Isles is seconds away from civil war.
In The Daleks Master Plan the Daleks have got back the last component of the weapon with hwich they hope to conquer the star system and the Doctor doesn't even know if he can get back to their base to stop them.
In The War Games, the Doctor pragmatically summons his people, the Time Lords, knowing that he will then have to face their judgement and even the ever-optimistic Second Doctor knows he cannot run from them any more. By the end of the story, the Time Lords have separated the Doctor from his companions and he faces trial by his own people. This ended up the Second Doctor's tenure and finished off the black and white era of the program.
Logopolis, the final story of the Fourth Doctor (the longest running Doctor on television to date). Most of the universeOne tenth of the universe, to be specific (which is still a hell of a lot), has already gotten destroyed, the situation has gotten so dire that the Doctor's future self had to bail him out, and the Master finally decides to take the remaining universe hostage.
The Trial of a Time Lord has the Doctor's trial suddenly have introduced a charge of genocide.
"The Sound of Drums" (which again features the Master) counts as a Darkest Hour, for the Doctor and for the Earth.
Possibly the darkest hour in not just the show's history, but in the whole of fiction occurs in The Pandorica Opens when it is revealed that the apparently Back from the Dead Rory is actually an Auton duplicate with the original's memories created as part of a huge trap for the Doctor by an alliance of all his enemies, who kills Amy just as she remembers him. The Doctor is shut in the Pandorica, an inescapable prison, despite his pleas for them to listen to his warnings of the impending destruction of space and time. It's in vain, because the TARDIS explodes with River inside of it, creating the cracks that set the season in motion in the first place and causing every star in every universe to explode at every moment in history, making it as if reality never existed in the first place. It all gets better in the finale though.
"A Good Man Goes To War", where the Doctor rose so high, and saw everything taken away, when Melody is taken away from under his nose, so she can be raised to kill him.
The end of the Chuck episode "Chuck Versus Sarah" is arguably the most depressing moment of the series. Not only has Sarah lost her memory, but after seeing her video logs, she starts to realize just how crucial the last five years of her life were and how different she became after falling in love. She sets out for Quinn with the knowledge that killing him won't actually make that any better, and Chuck watches the love of his life walk away from him knowing that she remembers almost nothing of their time together.
Sarah: I just wanted to tell you that I believe you. I believe everything that you told me about us. But the truth is, Chuck, I don't feel it. Everything that you told me about us and our story, I just ... I don't feel it.
For some viewers, depending on how you interpret the last few moments of the series, that doesn't actually get better.
The end of the episode "Spiral" in season 5 of Buffy the Vampire Slayer. Hellgod Glory has kidnapped Buffy's little sister/cosmic MacGuffin Dawn/The Key, and is going to use her to end the world. Plus, Giles is badly injured and the gang are stranded in the middle of nowhere.
In Angel, argubly one of the darkest moments is the end of season three where Wesley has betrayed the team and been abandoned, Cordelia has Ascended to a Higher Plane of Existence, and Angel's been trapped at the bottom of the sea by his own son.
In Star Trek: The Next Generation, the episode "Best of Both Worlds" marks a "darkest hour" for the crew and for the series which was facing cancellation. At the end of Season Three, Enterprise is damaged, the Borg have decimated the forces massed at Wolf 359, and they have captured Captain Picard assimilating his knowledge and their one trick shot with the main deflector dish fails and damages the ship. Riker is forced to take command of the ship and appoint his rival Lt Commander Shelby to be his first officer, as the Borg move to assimilate Earth. That's about as bad as it gets on TNG.
The cliffhanger at the "Best of Both Worlds, Part 1" (the season finale) has Riker order their hastily-assembled Wave Motion Gun fired at the Borg ship, with the assimilated Picard onboard. Part 2, the 4th season premier, has it get even darker in the opening scene, as said Wave Motion Gun, the most powerful weapon the Federation has ever created, hits the Borg ship and does absolutely no damage.
Star Trek: Deep Space Nine has quite a few involving the Dominion. The two most likely candidates occur when the station is abandoned at the end of season 5, and is not recaptured until 6 episodes into the next season, and "In The Pale Moonlight", when it appears that Senator Vreenak has discovered the falsified evidence Sisko and Garak had made to get the Romulans to join the war.
Season 4 ended with such. Teal'c last seen being taken by Apophis' Dragon. Then, because of the effects of the sun blowing up on hyperspace windows, the ship belonging to SG-1 is flung galaxies away, with zillions of years at maximum hyperspace between them and home. Just after that sank in Apophis comes through the same window and is right on top of them, his command ship docking with theirs the way theirs would dock with a pyramid.
Season 5 leads up to this: despite defeating Apophis once and for all at the start of the season, one by one, Earth and its allies are targeted for destruction by Anubis; the Tollan are destroyed, the rebel Jaffa and Tok'ra are scattered, and Earth escapes a Colony Drop unscathed (barely). Anubis turns out to have Ancient technology that can rival the Asgard, and Thor gets his brain sucked out. Oh, and Daniel Jackson is dead. They're screwed, and the next season doesn't give them much more hope.
It starts with Anubis attacking the Earth by using a device that will pump the Earth Stargate with so much energy it will explode, destroying all life on Earth. They manage to defeat his plan by strapping the active gate onto a recently-invented starfighter and blasting it into space, but that still doesn't stop the gate from exploding. Luckily, they have a spare. But Anubis is still out to get them, creating a weapon that blows up planets, and trashes other Goa'uld warships by the dozen without breaking a sweat, and uses it to blow up Abydos. The whole of Seasons 5 and 6 play out like a huge Darkest Hour. Things don't get better until the Season 7 premiere.
Happens frequently in Power Rangers, especially in the post-Zordon era where each season is self-contained. However, the Zordon era had several memorable ones;
First is part 4 of the Green With Evil saga. The Power Rangers suffer their worst defeat at the hands of Goldar, Scorpina and the Green Ranger, the Megazord is catastrophically damaged and Zordon is still missing with barely any chance of returning.
Second is the finale of Power Rangers Turbo. The Megazords, the Rangers' weapons and soon the Turbo powers are completely destroyed. Zordon has been captured by evil forces and the Power Chamber is leveled by a full-scale invasion from Divatox's army with no chance of Dimitria returning. It ends with the now-powerless Rangers blasting off into space with barely any direction of what to do.
Third is the final episode of Power Rangers in Space, Countdown to Destruction. The evil forces have a grip on the whole universe and the Rangers are outnumbered with most of their Megazords destroyed.
In the first episodes of season 3, the New Caprica arc. Most of the insurgency's leaders are held prisoner on the planet. The free ones, Saul, Anders and Galen are increasingly desperate, with Galen getting careless after Cally is arrested and Saul unhinged after being tortured. Starbuck is missing, held prisoner by Leoben and subjected to Mind Rape with no way to reach her husband or allies. On the Fleet, the two Battlestars are undermanned and have no viable means of penetrating the planetary defence. William and Lee are in increasing disagreement on what to do, feeling hopeless and unable to help the people they love.
Starting at the middle of season 4… The Fleet finds Earth after years of searching, but the whole planet is a radioactive wasteland. The friendly cylons have been all but decimated, with only one sheep surviving. Galactica herself is wounded and falls apart with old age. People fall prey to suicidal and auto-destructive behaviors, a situation that culminates in a bloody mutiny. The one child that symbolizes humanity's future is kidnapped by the bad cylons… and it keeps getting worse until the beginning of the Series Finale.
Let us not forget that the ENTIRE SERIES takes place immediately following the deaths of all but 50,000 humans, and the decimation of 12 worlds, each comparable in population to modern Earth.
LOST, season 6, episode 14. The ep is called "The Candidate", but could very well have been called "Darkest Hour" instead. The Man in Black is in full-on Kill 'em All mode, 4 main characters are dead—including the only person capable of piloting the Ajira plane—and the submarine has been destroyed, meaning there's no way of getting off the Island.
Babylon 5 has the episode Hour of the Wolf, where The Hero is dead after his Heroic Sacrifice, but didn't even manage to kill Morden. Garibaldi has been captured by someone, the Vorlons are done with what little diplomacy they did before, the League is taking their cues from Dying Like Animals, Londo sees his premonition of Shadow ships over Centauri Prime become true and Emperor Cartagia is planning on turning the Centauri homeworld into a giant funeral pyre to light his way to godhood. The Vorlons and the Shadows haven't started shooting yet, but they've thrown out the rules of engagement so it's only a matter of time.
The two-part opener of Merlin series four is called "The Darkest Hour." Furthermore, the tagline for the season as displayed on the posters is: "The darkest hour is just before the dawn." It's also a line of dialogue in the first episode, as said by Prince Arthur.
Camlann in the Series 5 finale. If you know the myths, you can guess. Only this time, Merlin breaks out of the cave and performs a Big Damn Heroes, although not in time to save Arthur.
All of the Supernatural season finales feature Darkest Hours, but the fifth season takes the cake. Sam is possessed by Lucifer, their last chance at stopping the Apocalypse failed, and it seems inevitable that Lucifer and Michael will have their showdown and tear the world apart. Even Castiel, a freaking angel, says its hopeless.
The penultimate episode of season eight comes close. Crowley has a list of everyone the Winchesters have saved, and he's going to kill one every twelve hours unless they agree to his terms. He even gives them a head start on the third victim just so they can watch her die. Faced with every scrap of good they've managed to do in eight years being erased, Sam seriously considers giving up.
The Darkest Hour for the Super Sentai franchise was shown in the crossover movie with Kaizoku Sentai Gokaiger and Tensou Sentai Goseiger as Earth is invaded by the Zangyack for the first time. They're beaten back, but the Sentai are left powerless. Near the end of the series, the Gokaigers are dealt their own moment when the Zangyack invade again and their Greater Powers are useless against them.
Warhammer 40,000: The Horus Hersey. Horus has besieged Terra, and the traitor legions have ravaged the entire planet, and the Emperor and only 3 of his Space Marine legions are all that stand against Horus and his 8 traitor legions.
The Dark Age Era in Battletech, the Exarch of the Republic of the Sphere Devlin Stone disappears, and the HPG network collapses from an unknown attacker, this riles every faction to turn on each other.
Arguably, Rock and Roll circa 1960. Elvis had turned to Frank Sinatra-style pop after his Army hitch, Eddie Cochran and Buddy Holly were dead, Carl Perkins had never really recovered from his car accident (and was playing mostly country), Chuck Berry and Jerry Lee Lewis were reeling from sex scandals, and Little Richard had quit to become a minister. It got better.
Explicitly invoked in The Devil Came Back to Georgia.
Johnny did you ever know that time keeps marching on
The coldest hour is the one comes just before the dawn
The Devil's Back in Georgia will you stand up to the test
Oh will you let the Devil be the best.
In choral settings of the Christian Mass, the music often lands in a minor key and slows down in the section of the Credo when Christ is crucified. When, in the next sentence, he is resurrected, the music perks right up into a major key and the tempo moves briskly along.
Without question the absolute darkest hour in Ludo's rock opera The Broken Bride is when the Time Traveller is at the apocalypse and decides to destroy his Time Machine, marooning himself there and severing himself from his beloved wife forever, to release the only things that may have a chance at destroying the zombie-making, soul-devouring Dragon: Pterodactyls.
Shinedown references this in their song, "The Sound of Madness." Potentially subverted, though, as the following line gives a potential Hope Spot:
The darkest hour never comes in the night; When ya gonna wake up and fight?!
The Manual (the Timelords' guide to creating a #1 hit single, no money or talent necessary) tells its user to schedule a week in the recording studio actually creating the single, and warns that Tuesday will be wrecked by depression and self-doubt. The only solution is to press on: by Wednesday, everything should start to make sense again.
The point of Wednesday 13's song, "We All Die:"
No matter what, you always put a smile upon my face
Just know that I love more than anything, just in case
Wicked: "No Good Deed Goes Unpunished! All helpful urges should be circumvented - no good deed goes unpunished! Sure, I meant well, well look at what well-meant did!" Dead little sister, Villain with Good Publicity as powerful as ever, Beloved teacher reduced to bleating, love interest in chains and torment, and best friend is accomplice to all this.
Two in Man of La Mancha: One is for Aldonza, after being gang-raped by the muleteers. Then Don Quixote himself suffers this after the Knight of the Mirrors breaks his spirit.
Spring Awakening: Melchior comes home to find his love interest and their unborn child have been killed by a failed abortion, making it all his fault, and he's reminded that best friend committed suicide, and it's also his fault, indirectly. And this is not helped in the original German play, when the ghosts of his friends actually appear to try to make him commit suicide and join them. Some friends.
Les Misérables has a Darkest Hour for each of its main characters, it seems. For instance, Fantine's beg: "I never did no wrong / My daughter's close to dying / If there's a God above / He'd let me die instead." The first act concludes with the Dark Reprisemedley "One Day More", which is the story's overall darkest hour.
"Gentlemen, we are about to brave the storm in a skiff made of paper." While history teachers forevermore would trumpet the signing of the Declaration as the birth of the United States of America, at the time the Founding Fathers knew that that "skiff made of paper" would have been a far safer bet - they faced another decade of war with a third of the Colonies on their side in a ragtag militia facing the might of the British Imperial Navy and knew they faced years of hardship and a charge of treason should they fail. John Adams might have been able to "see the rays of ravishing light and glory... through the gloom," but he also knew what they faced. There was very little joy in Independence Hall that day.
The Darkest Hour was yet to come: the Continental Army was soundly thrashed in the initial engagements at New York, and the broken remnants fled across New Jersey desperately attempting to escape the British. It was this that prompted Tom Paine to write "These are the times that try men's souls...."
In The Magic Flute, when the Queen of the Night asks Tamino to rescue Pamina, she asks him to help in "a mother's darkest hour."
The ending of Dreamfall: The Longest Journey: April Ryan was hit with a spear and tumbled into the water, never to emerge; Kian Alvane, the 'apostle' of a religion that converts by killing, had a crisis of faith and was promptly imprisoned; Zoe Castillo, the main protagonist, was sent into a permanent coma.
The beginning of the third chapter of Hordes of the Underdark, at least until you talk to the Reaper. You've just been imprisoned in Hell, your companions are gone, and Mephistopheles is loose on the Material Plane, currently heading towards the surface world with his undead army.
For that matter, the beginning of the second chapter of Shadows of Undrentide.
The final sequence of the most recent translated module of the Bastard of Kosigan saga, at least for players who chose to ally themselves with Mordred: Modred and Alex are dead, the French are overrunning your city, the Burgundians are too far away to arrive to help in time, and depending on some other choices you made there could be many other things going wrong.
Knights of the Old Republic: The party has been imprisoned by Admiral Karath, the Ebon Hawk locked up in the docking bay, Darth Malak is on his way to take possession of the party, and depending on your choices you may be forced to rely on the skills of a snot-nosed teenaged Twi'lek to survive. Karath uses his last breath to screw with Carth's head, and Malak has a Tomato Surprise. Alternately, if you play Dark Side, you can turn the ending into one of these.
The ending of Dragon Age II: the underlying tension between mage and Templar has finally exploded into open conflict, the Chantry is working on a major schism, and just to put the icing on the cake Orlais is eyeing Ferelden again. There are also hints of Tevinter regaining its power and the Qunari gearing up for another invasion attempt.
Mass Effect 1: The Citadel fleet has been demolished by the Geth, Soverign and Saren are working to open the relay to bring the rest of the Reapers in from dark space, and you have one minute to make it past at least four Geth colossi to get to the Conduit before it closes.
Mass Effect 2 opens with The Herodying, along with the Normandy. You're then brought back to life by a terrorist organization, because another group of advanced enemies is working for the Reapers, and the Council has spent two years convincing themselves that the Reapers aren't real. Oh, and you're on a suicide mission to bring down said group.
Mass Effect 3 is pretty much a game-long example, but the loss of the VI on and subsquent Fall of Thessia in particular is handled as an in-story Darkest Hour. Everyone aboard the Normandy, especially Liara, who also realized on that mission that the entirety of her species' history was a lie, is really devastated after the mission. During the debriefing and talking with crew members after the mission, you see Shepard is just inches from a Heroic BSOD. And while all this is going on, the turians, the most powerful military in the galaxy, have gone into a full-blown retreat from their homeworld Palaven.
In Final Fantasy VI, an insane megalomaniac has massacred the Espers, destroyed the balance between the Warring Triad, ravaged the world irreparably, attained godlike power, obliterated the heroes' airship, and scattered said heroes to the four winds. As a direct result of his actions, magical beasts run rampant over what's left of the world, what little vegetation is left is dying, humankind is dwindling, and, once the player resumes control of Celes, she's told that she (and Cid) is probably the last survivor anyway, with everyone else on the island having thrown themselves off a cliff in sheer despair... while she was in a year-long coma. In a desperate bid for any sort of hope, Cid and Celes adopt each other as grandfather and granddaughter, but he falls ill and is bedridden. Then, if Celes fails to keep him healthy by feeding him strong, quick-moving fish, he dies, at which point Celes loses all will to live and takes a flying leap off the cliff herself, leaving a Sparkling Stream of Tears in her wake.
The one ray of hope that might save the planet can't work because Sephiroth is blocking it, so the heroes have to lay siege to a series of caves in the middle of a frozen wasteland protected by an energy shield to fight a godlike superbeing just for the planet to have a chance at survival.
Two in Final Fantasy X. First, at Bikanel and immediately thereafter in Bevelle: Tidus (and the player) has finally learned just what will happen to Yuna when she performs the Final Summoning while Home has fallen to the Guado; Yuna is kidnapped and forced to marry Seymour, and when the others try to rescue her, not only are they thrown into a subterranean maze to die, but Yuna is put on trial for standing up to the maesters and discovers the truth at the heart of Yevon. The second comes near the end of the game where, after nearly all the Ronso are killed by Seymour and the party has vanquished Yunalesca, Mika passes on to the Farplane and abandons Spira and the party is left not knowing how they will stop Sin without the Final Aeon.
Final Fantasy XIII has several, but probably the most notable one is in Chapter 11. The party escapes Cocoon and lands on Gran Pulse, but can't find any answers or survivors, only ruins and wild beasts. Then, Hope's brand advances another stage, reminding them of just what they face. The last hope lies in Oerba, Vanille and Fang's old village - and when they actually reach Oerba, all they find is ruins and Cie'th.
During the second arc with Queen Elencia. Ludvec kidnaps Lucia, the Greil Mercenaries and Bastian are nowhere to be found, your main army with the most competent warriors are sidetracked and delayed by an enemy ploy and Ludvec surronds your last stronghold with a massive army of traitors and usurpers.
In the Third Chapter, thanks to Skrimir's idiocy, Naesala's treachery and Begnion's bastardry, the Gallian forces are trapped in enemy territory with the world's superpower on one side and Daein, which holds quite a few old friends, closing in on the other. They are forced to stage a full scale retreat losing the territory they gained and some of it they started with.
The game counts as one for Daein. It opens with them under a positively brutal occupation in which Begnion commits multiple atrocities including labor camps and murdering the citizenry. When that's over, Lord of the Incompetent, Pelleas, gets looped into a Deal with the Devil to serve Begnion which, in short, reads if you disobey every single Daein citizen will die of an magical incurable plague. Then they get wrapped in the the Gallian-Begnion war in which the Greil Mercenaries proceed to beat the crap out of them. THEN the an alliance of Crimea, Gallia and the bird tribes proceeds to march through Daein to Begnion with Daein losing every battle. Their bad luck doesn't end until the event that, strangely, is the world's Darkest Hour which Daein's Hope Spot.
The last and biggest occurs when members of the dragon tribe side with Micaiah and Daein. This means that the world is at war and that Yune, Goddess of Chaos is going to awaken. By sheer luck, the heros manage to find out the secret to awakening her peacefully just in time. Unfortunately, this also awakens Ashera, the Goddess of Order who proceeds to turn every single person, warrior, peasant, or little child, into stone.
Chrono Trigger has this just after you confront Queen Zeal in the Ocean Palace. Lavos woke up, knocked out the entire party with one attack, obliterated Crono, and destroyed Zeal. Schala teleported the party out with her magic, but she was caught in the Ocean Palace as it collapsed. The Epoch is gone, the time gate out of 12,000 BC is still sealed (and without Schala, there's no hope of breaking the seal), and Dalton and his troops are declaring sovereignty over what's left of the world. Just to add to that, the closest thing the party has to an ally is the person they've spent the first part of the game trying to kill.
In Chrono Cross, after the visit to Fort Dragonia. Lynx pulls a Grand Theft Me on Serge, turns his party against him, stabs Kid when she figures out what's going on, and throws Serge into a dimensional void. Even after Harle helps Serge out, he's still stuck in Home World, separated from all his friends, stuck in Lynx's body, while Dark Serge is doing god-knows-what in Another World.
Metal Gear Solid 4 has the microwave tunnel scene. As you continue to hammer the triangle button, the screen is split between Snake moving down the hallway, falling to his knees as his equipment explodes, having to crawl to the end, while the top portion shows his allies about to lose their respective battles. Raiden gets surrounded and stabbed by FROGs, Johnny and Meryl run out of ammo as an endless wave of enemies continues to charge them, and Metal Gear RAY mounts the battleship and prepares to fire on the bridge. This continues into the next scene and gets even worse, with Snake being overwhelmed by Mini-GEKKO and screaming Otacon's name as Otacon practically has a breakdown when it looks like he's not going to be able to upload the virus in time. All played to an absolutely heartrending soundtrack. Things looked pretty bleak before, but that sequence has players nearly breaking the controller from bashing the button so hard, praying that everything will turn out okay.
The programmers even made it more tense for the player. As Snake progressed through the tunnel, the speed at which the button had to be pressed slowly increases, to the point of using both hands for rapid fire button annihilation.
MediEvil 2 has this at the end of the Whitechapel level.
In the Spyro the Dragon game Dawn of the Dragon, the climax has a type three one of these. Ignitus performs a Heroic Sacrifice, Malefor takes over Cynder's mind and turns her on Spyro, this causes Spyro to go over the Despair Event Horizon. A Hope Spot occurs when Spyro saves Cynder with the Power of Love, but is quickly crushed when, while battling Malefor, the Great Destroyer finishes its path, beginning the planet's destruction and forcing the two heroes to battle Malefor as they plummet to the planet's core. They after a long brutal battle they overcome Malefor, causing him to be sealed away and Spyro saves the planet, almost killing them both in the process.
The submarine in Ghost Trick. After saving so many lives so many times, Sissel and his friends are left in a leaking metal coffin slowly falling to the bottom of the cold sea. They are utterly alone, without so much as a telephone line as a way out, and those of them that can't die will be left alone in the dark ocean forever.
In Super Paper Mario,Sammer's Kingdom gets destroyed by the Void, you're forced to fight your own Brainwashed and Crazy brother, then find that the Pure Heart that was located in the world that just got obliterated has been stripped of its power, no one has any idea of how to fix it... and then The Dragon shows up in between chapters to off your entire party in one go.
The Darkest Hour in the last GDI mission of Command & Conquer - Tiberian Sun - Kane's World Altering Missile is set to launch in 3 hours. And ICBM launchers will destroy the GDI orbital command center Philidelphia to boot.
Homeworld has a Darkest Hour of its own. It's not during the third level, but the last, where you have finally found your Homeworld. Unfortunately you've got several enemy fleets between you and it, out for your blood and Fleet Command is not responding...
Super Metroid. A giant Metroid appears. You can't kill it with any of your weapons. It latches onto you, and drains your health faster than you being submerged in the acid in Ridley's lair with the Power Suit and nothing more. No weapons can repel that monster. When you're in your very last HP point, it stops, gets off and starts vocalizing. Do you recognize those squeaks? It's Baby! It then flies off, leaving a clear way to a recharge station.
Another comes in the battle against Mother Brain. It uses a beam that not only presses Samus to the wall, it disintegrates her ammo as well. No matter how much you fight, it'll keep doing it until you can't stand anymore, then it batters you up with a few more shots and charges the death beam again. And then Baby latches onto its face.
Tales of Monkey Island has one: In Chapter 4, Guybrush watches Morgan die from a stab wound (which had been inflicted by LeChuck). As if that wasn't enough, he and Elaine get caught in clamshell traps set up by De Singe just as the former is finishing the Feast for the Senses for La Esponja Grande; and after he destroys De Singe and cures everyone of the Pox of LeChuck, the villain himself breaks free, creates a bit of a Hope Spot for Guybrush and Elaine by temporarily freeing them, and then erases it by killing the former and capturing both the latter and the sponge. While Guybrush is thinking up some means of escape in the Crossroads of the afterlife, LeChuck knocks Winslow off the Screaming Narwhal and sets it adrift at sea, damages Flotsam Island, by destroying many of its inhabitants, destroys Spinner Cay and its many Vaycaylians, damages the entire Gulf of Melange and makes it his own Villain World. Right after Guybrush creates another Hope Spot and opens the rips in the Crossroads, the villain gets his chance to erase it again by tossing the sponge into the rip and drawing voodoo power from the Crossroads. And to make matters worse, Elaine agrees to be turned into his demon bride who then sprays Guybrush with voodoo root beer, zapping him back to the Crossroads! A truly dark hour indeed!
Chapter 6 of The Reconstruction. The Watchers are dead, the world is in ruins, and an all-powerful "Lord-God" is sweeping up what little remains. The main characters are the only remaining hope for reconstruction.
After the Lava Caves in Baten Kaitos: Eternal Wings and the Lost Ocean. Geldoblame is dead, the five End Magnus are in the hands of The Chessmaster, and Kalas has gone to The Dark Side. The party is scattered, with Xelha being locked up in the Imperial Fortress, the others are who-knows-where, and Kalas has disowned the Guardian Spirit. It's ultimately an example of the third type of this trope, as there's several hope spots before the happy ending.
A bit early into Dawn of War II, you have been facing an Ork invasion and have only recently found the Eldar mucking around the Blood Ravens' recruiting worlds. Then, Tyranids arrive and Captain Thule, who was in command of the whole affair, is mostly killed by a Tyranid Warrior that gets away. So at that point, you've got an Ork Waaagh!, an Eldar strike force and a Tyranid tendril creeping on your recruiting worlds and only two Space Marine Companies (IV and X), bereft of a leader to fight them back with. Sergeant Tarkus even uses the exact words of the trope to describe the situation.
And the Chapter is terribly, terribly understrength after a botched campaign in Kauvara, in Dawn of War : Soulstorm.
Battlefield 3. Campo and Matkovich are dead. You killed Cole. Dima failed to stop the destruction of Paris via suitcase nuke. The OGA refuses to believe that Solomon is the Big Bad, and moves to lock Blackburn away in Leavenworth for a long time. And there's still one missing nuke.
H.A.W.X. 2, at the end. Most of the squad is dead, the Russian general has access to the laser satellites, and nukes are launching all over the place.
The beginning of the final day of Phoenix Wright: Ace Attorney: Justice for All, case 2-4. Maya's been kidnapped by a professional assassin, who wants him to get an acquittal for the client-of-the-week in exchange for Maya's life. Phoenix then has to spend the first day breaking one of the biggest woobies in the series to achieve his goal, only to find out that his client is guilty. On top of that, just when the player thinks they found out where Maya is being kept, the assassin slipped right out of the police's grasp, leaving them back to square one on where to find her, the player is given a You Bastard moment by said woobie, and now Phoenix has to decide between proving his client guilty or saving Maya's life. All while the client is standing there and mocking you.
In Dark Souls before the player character escapes the northern undead prison. The First Flame is dying, and when it does all light and fire shall go out with it. As a result much of the world is suffering through endless nights. The world has also be devastated by a curse of undeath called the Dark Sign and many, many civilizations have collapsed as a result. In a twist, there is some doubt (in-universe and out) over just how bad this Darkest Hour really is. Darkstalker Kaathe believes the Age of Dark is not only inevitable, but that it could be a good thing in the long run. Kingseeker Frampt believes the Age of Fire is worth preserving at any cost. Ultimately it's the player character's choice who to believe.
Paula: I can't think of anyone else... someone... anyone... please help us.
Paula's call was absorbed by the darkness.
X Rebirth combines this with After the End. One year after the events of Albion Prelude, the Argons' attempts at creating AGI ships caused the Xenon to become so powerful that the Ancients are forced to shut down the portal network just to keep them from overrunning the galaxy. Fast forward a thousand years, and the Community of United Planets has collapsed into complete anarchy, everyone is forced to scavenge old tech for resources, conflict is omnipresent, and all the while, both the Xenon and the Kha'ak have been biding their time and strengthening their forces, waiting for the perfect opportunity to strike...
Call of Duty: Black Ops near the end Dragovich was almost ready to signal hundreds of sleeper agents in the USA to release Nova 6, and President Kennedy will launch a nuclear strike should things get worse.
Resistance 3 opens in this manner. The Chimera have wiped out all organized opposition. All human governments have collapsed. 90% of humanity is either dead or converted. The remainder has been forced into small enclaves relying on Hit-and-Run Tactics to survive. And the Chimera are working on terraforming Earth to make it more suited to their physiology, which would render the planet inhospitable for the surviving humans.
This tends to happen in Kingdom Hearts due to the practice of bringing the protagonist close to death (or the metaphysical equivalent thereof) between games to create in-universe justification for his being reset to level one. Naturally, while the hero is thus incapacitated, the villain has near-free reign to accomplish his goals as the hero's allies try and fail to cover for his absence.
Baldurs Gate 2 has this when the party finally arrives at Spellhold. It doesn't take long before both people who can bring you to the island betray you: Saemon Havarian turns out to be working with the vampires, and the vampire's leader, Bodhi, turns out to be working for Big Bad Irenicus. And then party member Yoshimo (again, if you brought him with you) betrays you as well, and the entire party is captured by Irenicus, who's taken control of Spellhold. He then proceeds to rip out your soul and leave you for dead. If there's any consolation, the party is finally reunited with Imoen, and Bodhi disobeys her orders to execute you because she wants to toy with you a bit more.
Even Rosenkreuzstilette gets one of these awful moments. To start things off, while Tia's pleading for Count Michael Zeppelin to stop doing the wrong thing and return to the path of righteousness, he gets suddenly and deliberately obliterated into a burst of flames from behind by a lightning bolt. Then his daughter Iris appears calling him a useless old man without remorse and then proceeds to kick off Tia's Heroic BSOD by attacking and fatally injuring her with another attack. When Tia desperately wants to know what the hell is going on, she gives off a lecture revealing the Awful Truth to both her and Lilli to both of their horrors, throwing Tia even further into her Blue Screen of Death mode; the fact that she started RKS's coup against the empirefor kicks, and that she killed her own father to make his adoptive daughter Zorne suffer without regret. And after that, she decides she doesn't need Tia any further so she's about to finish her off and kill her with one last attack. Had it not been for Freu coming in with her Big Damn Heroes moment, her attack would've done so and Iris would've been free to continue doing as she pleased with no one to stop her and therefore made it all result in a Downer Ending for everyone else.
The start of the final act of Diablo III is one of these in spades. To recap: Diablo is back courtesy of Adria pulling the mother of all betrayals. Leah is no more thanks to Adria using her as the vessel of said rebirth. Diablo has become the Prime Evil, the sum total of all Seven Great Evils in one being, thanks to the Black Soulstone that you so helpfully put the Evils into for Adria. And Diablo and all his forces are now running roughshod over the High Heavens themselves, with extra despair points due to Auriel, the Archangel of Hope, being taken prisoner by Rakanoth, the Lord of Despair. Only when you free her do things begin to look up, though you still have a lot of demonslaying to do!
Pokémon Ruby and Sapphire and Emerald'': You tried to stop Archie/Maxie, but Kyogre/Groudon woke up anyway and is trying to flood/bake the entire Hoenn region. And in 'Emerald', they're going at it with each other and the sun and rain are both going on. Better go wake up Rayquaza before they desroy everything...
The final chapter of Socrates Jones Pro Philosopher begins this way. Socrates accidentally gives a badly-thought-out answer to the question of the nature of morality— and he only had the one chance to do so. His only remaining hope is to convince the Arbiter that his accidental answer is correct...
Sluggy Freelance, as might be expected from such a plot-heavy series of its length, has at least three examples.
The first is at the end of Chapter 12, when Gwynn is in an apparently irreversible coma, and Torg and Zoë are trapped in pre-Norman Britain in an Army of Darkness parody.
The second, a pastiche of such moments in horror films, in chapter 32, after a group consisting of the majority of the storyline's surviving cast, including Torg and Bert, are ambushed and apparently killed in the space of a single strip. It would be just a one-strip fake out like the one two chapters later, except that only Torg and Flaky - and not Bert - actually did survive.
The Order of the Stick: Azure City, a major bastion of Good, is overrun by an army of hobgoblins. The goblin cleric and evil lich that command them thus get access to a gate holding a universe-devouring monstrosity. Most of the paladins are wiped out, and the strongest is taken prisoner. The survivors from the city are living on boats while trying to find a new place to settle. The leader of the heroes has been killed during the battle. The surviving team is separated and unable to contact each other and the wizard of the party has now defected at the urging of his/her personal demons and is manipulated into accepting a Deal with the Devil and is now teetering on the brink between heroism and villainhood.
Oh, and that Gate? It gets destroyed during the battle. And while that may mean that the villains can't harness its powers, it now means that there's a gaping hole in reality and the seal containing the Snarl has been significantly weakened. Oh, and while Vaarsuvius may have come to his/her senses, he/she still owes his/her soul to the IFCC, who still seem interested in using him/her as a pawn. On the bright side, however, O-Chul's capture allowed him to befriend the Monster in the Darkness, and seems to have started it down the path to a Heel-Face Turn, so some good came of this mess.
The trolls are first introduced right in the middle of their Darkest Hour. They finally beat the game, and are going to claim their reward...when Jack shows up and starts killing everything, forcing the trolls to hide out on an asteroid and wait for death.
Another one happens towards the end of Act Six Act Three. Three of the characters are on Derse, which initially seems fine... untile Draconian Dignitary activates the Red Miles, which end up killing Jane (who was doomed to be stuck on the moon anyway) and Roxy (who was seconds away from starting a new session). Lil' Sebastian manages to get Jake back to his island and sinks to the bottom of the ocean, leaving the boy unconscious. Dirk's dreamself loses consciousness in the process of saving Jake, and was scant seconds away from corpsesmooching Jane. Luckily, Dirk manages to activate Jane and Roxy's dreamselves while permanently becoming his own dreamself, and he and his robots ender the Medium. Seems fine, right? Too bad Caliborn wakes up, frees himself, and starts up his session while Lord English destroys an entire dreambubble full of dead Trolls and Humans.
El Goonish Shive: In the ninth part of the Sister II arc Nanase futilely tries to talk to Abraham to convince him to spare Ellen's life but he cuts her fairy doll avatar down. This hurts her unimaginably as she can feel everything but she creates another avatar and tries again. Abraham thinks he is fighting puppets controlled by the elf he defeated earlier and refuses to even acknowledge what she is trying to tell him believing it to be trickery. Instead, he cuts the avatars down as fast as Nanase can create them each time causing her physical pain but she keeps trying over and over again. All this while every mortal being in the area who could possibly help her has either been put into a deep sleep by Abraham or is unaware of her plight.
Bittersweet Candy Bowl has December, when Mike tells Lucy just how he feels about her. Or does he? At the same time, Paulo is worried he is going to hurt his girlfriend due to his longtime crush on the now-free Lucy and Abbey finds out that his mother died years ago, after a brutal beating she received from his father. And then hid that she had died from her children, making Abbey feel like she had abandoned them instead.
Romantically Apocalyptic: There’s a pretty long period of time that functions as this, with many events making it worse. The biomass integrates Snippy, so now he’s mentally trapped in his past, and physically trapped in this monstrosity http://romanticallyapocalyptic.com/57. The biomass then finds Pilot, who Captain tells to rescue Snippy. He tries, and fails, and is integrated into the biomass too. So he’s also trapped in his mind. Then, a Hope Spot as the being known as the lifealope forms… but nope, it looks like the biomass is going to integrate or destroy it. And ANNET found Engineer and is going to kill him. For a comic that was previously just wacky humor, it takes a pretty dark turn.
There Will Be Brawl - the butchers are still on the loose, Princess Peach is still missing, and to make matters worse, Kirby has escaped from jail.
Whateley Universe example: the story "Christmas Elves". One chapter ends with Fey trapped and powerless in a magical circle so she can be mindslaved, Shroud gone, and Generator locked to a table and stabbed through the heart so hard that the athame goes through her and is stuck in the table.
The 9/11 attacks in the Global Guardians PBEM Universe. While rescuing people from the World Trade Center, four Guardians members were seriously injured (one to the point of being permanently paralyzed) and another killed when the towers collapsed.
The Powerpuff Girls - The Movie: The city's being destroyed by mutated monkeys, the entire city of Townsville hates them, and Mojo Jojo is holding their father hostage.
Weapons Factory: Outside the factory, Ray-Shielded Separatist super tanks are tearing through Anakin and Luminara's troops and blowing them to kingdom come, and inside the factory, Ahsoka is knocked out (again), and the Geonosians steal the explosives that were going to be used to blow the reactor, throwing a monkey wrench into Ahsoka and Barriss's operation.
At the end of Gungan Attack, Riff Tamson and his Sepratist forces have defeated and captured the Republic/Mon Calamari/Gungan Army and stands victorious on Mon Calamari, with only Ahsoka and Prince Lee-Char uncaptured.
At the end of the first half of Season Four, Slaves of the Republic, our heroes are all captured and enslaved by the Zygerrians and have no hope of escape, with Anakin as the Zygerrian queen's personal servant, Ahsoka caged above the queen's palace and being tortured without pity or mercy by the prime minister of Zygerria, and Obi-Wan and Rex broken by the keeper of the Zygerrian slave hub on Kadavo. It carries over to the next episode, Escape from Kadavo.
In Escape From Kadavo, during the rescue mission, Keeper Arguss activates the floor trap to the Togruta slaves' cell and breaks the controls to prevent Obi-Wan and Rex from turning it off, and Plo Koon can't move his ship for the rescue mission until the ray-shielded enemy cannons are destroyed, which are shooting at Plo Koon's fighter and gunship squadron.
One is the "Crossroads of Destiny" where Zuko does not complete his Heel-Face Turn, Azula backshoots Aang with lightning, nearly killing him, and the previously impenetrable Earth Kingdom Capital Ba Sing Se falls to the Fire Nation.
Another is the "Day of the Black Sun" where Sokka tries to lead an invasion of the Fire Nation during a solar eclipse. Instead, we learn that Azula knew about the invasion all along and the Fire Nation was ready. The end result was that the invasion failed, virtually all the troops were sent to prison, and the few remaining children had to hide out in the Western Air Temple. But it wasn't all bad—the thing keeping it from being a total downer was Zuko's long-awaited real Heel-Face Turn, heralded by an epic Calling the Old Man Out scene and badass lightning redirection.
Every season of Teen Titans has one of these occur during the season finale.
Season 1: The Teen Titans are infected with nanobots that will kill them upon Slade's command. To save their lives, Robin swears to serve Slade as his apprentice.
Season 2: Terra casts aside all compassion she once felt for the Teen Titans, ruthlessly attacks and attempts to kill them, and helps Slade conquer the city.
Season 3: Cyborg quits the Teen Titans so he can be leader of Titans East. Titans East, however, are under Brother Blood's psychic control.
Season 5: Though not technically the season finale, the culmination of the story arc involved the Brotherhood of Evil kidnapping every teenage superhero on the planet (with only five or six exceptions). The actual season finale also fulfilled this trope, at least if you were a Beast Boy/Terra shipper.
The last episode(s) of Danny Phantom where an asteroid is about to come hurtling towards Earth. Several attempts to create a Hope Spot occurs when the world sends missiles towards it, but they ultimately fail and the planet is left to bide their time till their doom. The protagonist and titular character has gotten rid of his ghost powers and the villain offers everyone another hope spot...in return for being named ruler of the world.
The concept of the "Darkest Hour" is a major part of Transformers philosophy, signifying a threat that seems to blot out all hope in the universe. The way to avert it is to bring all Transformers together against whatever threatens them - thus the phrase "Till All Are One". The animated movie is the example of this, but it recurs throughout different continuities.
ReBoot: The city is completely ruined, only the principal office has any power, and it's impossible to repair the city. The remaining population is holed up in the principal office and doesn't have the supplies to last very long. And to make matters worse a game has landed which will crash the entire system when the User wins. The only way out of this mess is to invoke a Deus ex Machina and pray for the User to intervene as the system crashes and everything fades to black. A couple of key strokes from the User and everything is fixed, including bringing back the dead.
In the season 2 finale, the Changeling Queen Chrysalis manages to defeat both the Mane Six and Princess Celestia, and take over Canterlot in a preparation for her horde to conquer Equestria. She's only defeated when Cadence uses The Power of Love to supercharge Shining Armor's shield spell, which banishes the changelings from the city.
The season 3 series finale: Darkseid has been resurrected and leads his armies in an all out attack on Earth, forcing all the superheroes and supervillains to join forces to save Earth.
The Season 2 finale is even more bleak: Braniac and Luthor are merged together, and the reserve League is occupied, dealing with the aftermath of Cadmus' attack on the Watchtower, leaving just the original seven* (Superman, Batman, Wonder Woman, Green Lantern, Flash, Martian Manhunter, and Hawkgirl) to fight him. Near the end, Braniac!Luthor is about to destroy Earth and has knocked out everyone but the Flash, who gets scared and runs away -or so the evil duo thought.
The first season premier has the massive breakout of the 4 super villain prisons, forcing all of the superheroes to unite against them.
Then Kang's massive invasion forces has swarmed all over the Earth, which forces Ant-Man to use his Ultron army.
After that Ultron nearly succeeds in a global nuclear apocalypse. Whew!
Happens to the titular Motorcity in the first part of the finale "Vega": Mike Chilton has been arrested and is to be executed, KaneCo bots are running amok and the Genesis Pod has been planted, the latter of which is set to wipe out the entire city and its people.
In the Futurama movie "Bender's Big Score", the Darkest Hour comes when the scammer aliens manage to buy out the Earth and exile its inhabitants to the moons of Neptune. The Earthicans end up teaming up with Robot Santa to take back their home.
The Black Death, so far the most horrific plague Europe ever had to face. In a span of three to four years, the population of Europe was reduced of one third. The general perception was that the Apocalypse was coming.
The Other Wiki attributes Winston Churchill as the Trope Namer for this phrase, having used it in speeches for the period of World War II where France had just fallen to the Nazis, they had turned against Soviet Union to the east and were launching The Blitz against Britain.
In Asia Imperial Japan has already conquered most of Southeast Asia, a major sign of this was the Fall of Singapore, which was the British stronghold on Asia. Then was the attack on Pearl Harbor, and the Japanese fleet was on its way to Australia.
The Cold War, for humanity as a whole. In a reversal of all indications from history, two powerful nations in an arms race, itching to defeat the other, did not go to war in a period of 40 years. With enough nuclear weapons to render the Earth uninhabitable many times over, and events like the Cuban Missile Crisis bringing tensions to alarming levels, where the public kept track of something called The Doomsday Clock, the Cold War ended peacefully.
The Cuban Missile Crisis deserves further special mention, here. It's one of the closest instances of nuclear war to date. Kennedy himself estimated the odds of nuclear war at somewhere between 1/3 and 1/2. The solution that prevented nuclear war was not even possible at first, and was a longshot from the beginning, relying on military and political leaders, as well as the personnel up and down the line on both sides, to put their faith in the hope that the other side (and their own) would avoid nuclear war at all costs. Leaders on both sides, especially at the worst parts of the crisis, were well aware that The End of the World as We Know It was likely if they didn't pull through.
Further, two out of the three Russian leaders whose approval was needed to launch their nuclear weapons had already given the OK. The only one who did not approve of opening fire was the captain of the submarine from where the missile was to be be fired. Thankfully, that was enough.
If life can be considered a story, the Permian-Triassic extinction needs to be mentioned here. 70% of land creatures died, and in the water, it may have been as high as 95%. The freaking trilobytes, survivors that they were, all went extinct. It took something that severe for the ancestors of dinosaurs to step up.
During the Libyan Civil War, Gaddafi's assault on Benghazi was this for the rebels. He had the superior forces, the rebel capital was certain to fall, and the promised Western support was nowhere to be seen. CuetheFrenchairforce, followed by 120+Tomahawkmissiles.
In late 2012, this began for The BBC — one of the world's most respected broadcasters — when an ITV documentary claimed that their legendary youth/children's show presenter Jimmy Savile, who had died the previous year to nationwide mourning, was actually a serial sexual offender who used his showbusiness clout and charity work to sexually assault children and young women while avoiding scrutiny from everyone from fellow BBC employees to authorities to the National Health Service. Worse, the initial testimonials from victims had been made for a BBC documentary that was quashed by higher-ups. After the documentary aired, hundreds of additional claims of wrongdoing by Savile were made, resulting in a Scotland Yard investigation and criticism from Parliament. (Between this and a separate report that falsely accused a British politician of pedophilia, the just-elected Director-General of the BBC resigned after less than three months at his post.) How The BBC can live this disaster down remains to be seen, especially when Savile himself can never be brought to justice.
Remember, dear tropers; the darkest hour is always before the dawn.