History Series / CrisisOnEarthX

* OutOfFocus: Aside from the leads of their said shows/teams (i.e. Barry, Iris, Kara, Alex, Oliver, Felicity, Sara, Stein, Jax, Mick) none of the other members of Team Flash, Team Arrow, Earth-38 or The Legends are given much focus, constantly involved, or receive nearly as much event long screen time. Downplayed with Team Arrow's B-Squad who actually make an appearance outside of the ''Series/{{Arrow}}'' portion of the crossover and show up at STAR Labs to help fight Oliver-X, while last year they were restricted to their episode of the crossover.

* SpecialEditionTitle: As per the tradition for crossover events, but taken UpToEleven where instead of combining each show's logos for each part, all the Lectcharacters are featured together in a special, unified title for this event.

* ZeroPercentApprovalRating: The Nazis are pretty much a given, since literally everyone at the wedding says in unison "I hate Nazis" when they crash the ceremony, though in a more subtle case shows Adolf Hitler in this light, astonishingly for the place he came from. Even in an alternate Earth where he took over the world and managed to live through a century, it's shown that he isn't even respected by his successors as Overgirl states in a private conversation with Dark Flash that Oliver-X is a superior Fuhrer than Hitler ever was.

* ArcVillain: The Füuhrer, a.k.a. the Dark Arrow, is the one calling all the shots, although he seems to be [[BigBadDuumvirate playing equally]] with Overgirl (which is justified because they're married) and the Dark Flash.

* PowerfulAndHelpless: Behold Overgirl. An Evil Supergirl, she has all of the power of her counterpart and has embraced the fact she's a PhysicalGod fully, which means she fights with even ''less'' restraint...and she's dying of a solar power overload which will make her explode at any moment, and there is nothing she can do to stop it. Most of the actions she and her Oliver take throughout the story are driven by the fact they are running out of time and trying to pull a "Hail Mary" (so to speak) and a lot of their conversations are tinged with the fact that Kara may die soon...and sure enough, once Overgirl finally explodes during the final battle, the evil Oliver Queen, the Fuhrer of Earth-X, pretty much pulls off a SuicideByCop out of despair.

* '''[[Characters/ArrowverseTeamArrow Team Arrow]]:''' Oliver Queen[=/=]ComicBook/GreenArrow (Creator/StephenAmell), Felicity Smoak/Overwatch (Creator/EmilyBettRickards), Curtis Holt[=/=]ComicBook/MisterTerrific (Echo Kellum), Dinah Drake[=/=]ComicBook/BlackCanary (Juliana Harkavy), Rene Ramirez/Wild Dog (Rick Gonzalez), and John Diggle/Spartan (Creator/DavidRamsey)

''Crisis On Earth-X'' is the fourth annual {{crisis crossover}} {{television serial}}, of Creator/TheCW's Series/{{Arrowverse}}, following ''Series/FlashVsArrow'', ''Series/HeroesJoinForces'' and ''Series/{{Invasion|2016}}'', and is told across ''Series/Supergirl2015'', ''Series/{{Arrow}}'', ''Series/{{The Flash|2014}}'', and ''Series/LegendsOfTomorrow'' with characters from ''WesternAnimation/FreedomFightersTheRay'' also appearing.

''Crisis On Earth-X'' is a 2017 {{crisis crossover}} {{television serial}}, told across Creator/TheCW's Series/{{Arrowverse}} franchise of shows based on Creator/DCComics: ''Series/{{Arrow}}'', ''Series/{{The Flash|2014}}'', ''Series/LegendsOfTomorrow'', and ''Series/Supergirl2015'', while characters from ''WesternAnimation/FreedomFightersTheRay'' also appear. It is the Arrowverse's fourth annual crossover, following ''Series/FlashVsArrow'', ''Series/HeroesJoinForces'' and ''Series/{{Invasion|2016}}''.

''Crisis On Earth-X'' is a 2017 {{crisis crossover}} {{television serial}}, told across Creator/TheCW's Series/{{Arrowverse}} franchise of shows based on Creator/DCComics: ''Series/{{Arrow}}'', ''Series/{{The Flash|2014}}'', ''Series/LegendsOfTomorrow'', and ''Series/Supergirl2015'', while characters from ''WesternAnimation/FreedomFightersTheRay'' also appear. It is the Arrowverse's fourth annual crossover, following ''Series/FlashVsArrow'', ''Series/HeroesJoinForces'' and ''Series/{{Invasion2106}}''.

''Crisis On Earth-X'' is a 2017 {{crisis crossover}} {{television serial}}, told across Creator/TheCW's Series/{{Arrowverse}} franchise of shows based on Creator/DCComics: ''Series/{{Arrow}}'', ''Series/{{The Flash|2014}}'', ''Series/LegendsOfTomorrow'', and ''Series/Supergirl2015'', while characters from ''WesternAnimation/FreedomFightersTheRay'' also appear. It is the Arrowverse's fourth annual crossover, following ''Flash vs. Arrow'', ''Heroes Join Forces'' and ''Invasion!''.

* '''[[Characters/ArrowverseTeamArrow Team Arrow]]:''' Oliver Queen[=/=]ComicBook/GreenArrow (Creator/StephenAmell), Felicity Smoak/Overwatch (Creator/EmilyBettRickards), Curtis Holt/Mister Terrific (Echo Kellum), Dinah Drake[=/=]ComicBook/BlackCanary (Juliana Harkavy), Rene Ramirez/Wild Dog (Rick Gonzalez), and John Diggle/Spartan (Creator/DavidRamsey)
* '''[[Characters/ArrowverseSTARLabs Team Flash]]:''' Barry Allen[=/=]Franchise/TheFlash (Creator/GrantGustin), Iris West (Creator/CandicePatton), Cisco Ramon[=/=]ComicBook/{{Vibe}} (Carlos Valdes), Caitlin Snow/Killer Frost (Creator/DaniellePanabaker), Joe West (Creator/JesseLMartin), Dr. Harrison "Harry" Wells (Creator/TomCavanagh), and Wally West/Kid Flash (Creator/KeiynanLonsdale)
* '''[[Characters/ArrowverseTheLegends The Legends]]:''' Sara Lance/White Canary (Creator/CaityLotz), Martin Stein (Creator/VictorGarber) & Jefferson "Jax" Jackson (Franz Drameh)[=/=]ComicBook/{{Firestorm}}, Mick Rory/Heatwave (Creator/DominicPurcell), Ray Palmer[=/=]ComicBook/TheAtom (Creator/BrandonRouth), Amaya Jiwe[=/=]ComicBook/{{Vixen}} (Maisie Richardson-Sellers), Nate Heywood/Steel (Nick Zano), Zari Tomaz (Tala Ashe), and Gideon (Amy Louise Pemberton)
* '''Kara Danvers[=/=]ComicBook/{{Supergirl}}''' (Creator/MelissaBenoist), DEO Agent Alex Danvers (Creator/ChylerLeigh), James Olsen/Guardian (Creator/MehcadBrooks), J'onn J'onzz[=/=]ComicBook/MartianManhunter (Creator/DavidHarewood), Winnslow "Winn" Schott (Jeremy Jordan) and Mon-El (Chris Wood)

''Crisis On Earth-X'' is a 2017 {{crisis crossover}} {{television serial}}, told across Creator/TheCW's Series/{{Arrowverse}} franchise of shows based on Creator/DCComics: ''Series/{{Arrow}}'', ''Series/{{The Flash|2014}}'', ''Series/LegendsOfTomorrow'', and ''Series/Supergirl2015'', while characters from ''WesternAnimation/FreedomFightersTheRay'' also appear. It is the Arrowverse's fourth-annual crossover, following ''Flash vs. Arrow'', ''Heroes Join Forces'' and ''Invasion!''.

* AllYourBaseAreBelongToUs: The Earth-X invaders occupy S.T.A.R. Labs, and then goes so far as to use its Pipeline to imprison the heroes.

* BigDamnKiss: Unsurprisingly, Barry and Iris, and Oliver and Felicity's, first kiss as husband and wife.

* DarkSecret: Earth-X's existence is treated as this -- even Kara was unaware of it, until Harry revealed it.

** [[AcceptableTargets Nazis]]. Even Mick, the least moral of the protagonists, stated several times in his team's series how he hates them, and Oliver has absolutely no issue suspending his ThouShaltNotKill rule for them, something that no one holds against him. According to Harry, this actually extends to the entire multiverse -- as he puts it, no ''sane'' person has ever willingly traveled to Earth-X, because it is that much of a CrapsackWorld.

** Tommy-X plays up the fact that his family is in constant danger due to the Third Reich. Oliver swears he will help protect him and his love ones from the Dark Arrow. Cue [[ILied Tommy's mocking laughter in a confused and pained Oliver's face]] before ingesting a CyanideCapsule, declaring his steadfast allegiance to the Führer.

** Given how Alex was absent when Barry attempted to explain the Multiverse to Kara, James and Winn, she was unaware of the concept of Doppelgängers, and is slightly confused when Harry mentions that there are 53 other versions of Kara.

** When the DEO is first trying to identify the Dominator Supergirl fights, one of Alex's guesses is [[SelfDemonstrating/Lobo Czarnian]].

** Especially the case for Diggle, who as opposed to usual, was left out of the events of the crossover entirely save for the final scene where he's only brought in to marry Barry and Iris. [[JustifiedTrope Justified in that he's still recovering from the nerve damage in his arm.]]

* PowerfulAndHelpless: Behold Overgirl. An Evil Supergirl, she has all of the power of her counterpart and has embraced the fact she's a PhysicalGod fully, which means she fights with even ''less'' restraint... and she's dying of a solar power overload which will make her explode at any moment, and there is nothing she can do to stop it. Most of the actions she and her Oliver take throughout the story are driven by the fact they are running out of time and trying to pull a "Hail Mary" (so to speak) and a lot of their conversations are tinged with the fact that Kara may die soon... and sure enough, once Overgirl finally explodes during the final battle, the evil Oliver Queen, the Fuhrer of Earth-X, pretty much pulls off a SuicideByCop out of despair.

* SomethingWeForgot: The heroes pull an epic LockAndLoadMontage as they [[PowerWalk march off]] to face the invaders...and then MissionControl learn Mick actually just stayed behind.

* SpecialEditionTitle: As per the tradition for crossover events, but taken UpToEleven where instead of combining each show's logos for each part, all the characters are featured together in a special, unified title for this event.

** Professor Martin Stein, having been fatally shot, forces Jax to sever the connection between them so the latter may live, and joins his first partner Ronnie Raymond in death. [[WidowWoman Caitlin]] even asks, while burying Stein, if he could say a hello to Ronnie for her.

* WellIntentionedExtremist: General Schott while [[JerkWithAHeartOfGold sympathetic]] to the Earth-1 refugees, still adamantly refuses to keep the warp gate back to Earth-1 standing long enough for them to return home. At least, at first.

* ZeroPercentApprovalRating: The Nazis are pretty much a given, since literally everyone in the wedding says in union "I hate Nazis" when they crash the ceremony, though in a more subtle case shows Adolf Hitler in this light, astonishingly for the place he came from. Even in an alternate Earth where he took over the world and managed to live through a century, it's shown that he isn't even respected by his successors as Overgirl states in a private conversation with Dark Flash that Oliver-X is a superior Fuhrer than Hitler ever was.

** In a deleted scene, Harry reveals to a very surprised Thawne, who tries to kill him, that after Zoom and Savitar, he has infused his body with nanites programmed to attack any speedster attempting to phase through his body. Thawne looks visibly disturbed at this. Why he doesn't simply snap Harry neck is a different issue.

!!! Episodes

* ArchEnemy: The New Reichsmen quickly become this for their good counterparts. [[spoiler:Except for the Dark Flash, as he's actually the Reverse-Flash, Earth-1 Eobard Thawne, and thus already Barry's ArchEnemy to begin with]].

** [[spoiler:Team Arrow comes to Heatwave and Killer Frost's rescue against Dark Arrow. Subverted in that he takes all of them down singlehandedly.]]
** [[spoiler:Citizen Cold saving several of the Earth-1 heroes from a Nazi firing squad. He was actually there to save Ray Terill, but Ray tells Cold that they should free them as well.]]
** [[spoiler:The remaining Legends finally arriving to rescue the heroes being held hostage at S.T.A.R. Labs, with Ray Palmer in particular being the one to save Kara from being cut open by Thawne.]]
* BigDamnKiss: Unsurprisingly, Barry and Iris, [[spoiler:and Oliver and Felicity's]], first kiss as husband and wife.
* BigNo: Dark Arrow, when [[spoiler:Overgirl explodes]].
* BigRedButton: One is used to [[spoiler:shut off the Earth-X Waverider's shields]].

** When facing off against the teamwork of Sara and Alex, Prometheus-X declares that today's wedding will also be followed by two funerals. The crossover ends [[spoiler:with two weddings after one funeral.]]
** The first battle between Overgirl and Supergirl ends with the former sending the latter plummeting back to the church, and Supergirl retaliated with a ShockwaveClap that disoriented Overgirl, causing Dark Arrow's BigNo. [[spoiler:The way the final battle between the two Kryptonians ends almost literally mirrors the whole thing, where Supergirl carries Overgirl to the ''atmosphere'' before detonating, and was then also followed by Dark Arrow's BigNo.]]
** In the VillainOpeningScene, Dark Arrow finishes off the Freedom Fighters' Guardian with an arrow point-blank to the heart. [[spoiler:The final battle in Central City ends with Oliver sending an arrow point-blank to [[KarmicDeath his Nazi counterpart's]] heart.]]

** The crossover upholds the Arrowverse tradition of cameos from former superhero television with [[Series/TheGreatestAmericanHero William Katt]] as the priest who gives Iris and Barry their vows moments before [[spoiler:[[DeathByCameo he's vaporized by Overgirl]].]]
** Susanna Thompson, who plays Moira Queen, makes a surprise voiceover appearance as [[spoiler:Earth-X's Gideon.]]

** When Oliver-X invades STAR labs, and give a lot of trouble to the heroes, the Team Arrow recruits arrive as reinforcement...[[spoiler:[[SubvertedTrope but don't end up faring any better]].]]
** After the Nazis have completely taken over STAR Labs, Felicity sends an S.O.S. to the rest of the Legends. [[spoiler:They only manage to arrive near the end of the event, but are a lot more helpful against the Nazis with Ray Palmer saving Kara's life.]]

** Part 1: [[spoiler:The leaders of the New Reich unmask themselves...and they are the Earth-X doppelgangers of Kara and Oliver. The third leader shows up, and it's Eobard Thawne.]]
** Part 2: [[spoiler:Iris and Felicity are trapped in a Nazi-occupied S.T.A.R. Labs as they watch the invaders lock Team Arrow, Killer Frost and Heatwave in the Pipeline, and the rest of the heroes find themselves in a concentration camp on Earth-X, with Kara's location unknown.]]
** Part 3: [[spoiler:The heroes on Earth-X fight the Nazis in the hangar with the portal to Earth-1, while Red Tornado-X is flying in ready to blow the place up, Flash and the Ray having failed to stop it. And Martin Stein is shot, to Jax's horror...]]

** The Flash combines his lightning attack with the Ray's energy burst to finally take out [[spoiler:Red Tornado]].
** All the heroes with ranged energy attacks worked together to destroy [[spoiler:Earth-X Metallo]].

** Oliver and Felicity's failed first engagement is constantly brought up as a reason why Felicity [[spoiler:doesn't wish to marry Oliver.]]

* CooldownHug: An inconsolable Jax [[spoiler:breaks down crying in Clarissa and Lily's arms after he reports to them of Martin's death.]]

* DarkestHour: It was in ''The Flash'' episode where everyone is at their most desperate, the situation going FromBadToWorse after a handful of {{Hope Spot}}s. The heroes only pick up their second wind at the start of Part 4. Ironic, since ''The Flash'' is supposed to be going back to its LighterAndSofter roots this season.

* EarlyBirdCameo: The Arrowverse's version of The Ray makes his debut in this story arc, and will be seen again in ''WesternAnimation/FreedomFightersTheRay''. It also features the first appearance of [[spoiler: Barry and Iris' daughter from the future, Nora]].

* EvenEvilHasLovedOnes: They are the leaders of the Third Reich, and yet Dark Arrow and Overgirl are deeply committed and in love with one another. Also, [[spoiler:his version of Gideon has his mother's voice]].

* ExpendableAlternateUniverse: [[spoiler:Earth-X Winn Schott]] hardly cares about endangering Earth-1 or the heroes of alternate earths. He just cares that the Nazis are not in his Earth.
* FairytaleWeddingDress: Iris' [[spoiler:during the first attempt at a Barry and Iris wedding.]]

* ForegoneConclusion: We know from the trailers from ''WesternAnimation/FreedomFightersTheRay'' that Overgirl and Dark Arrow will survive the events of the crossover. [[spoiler:Ends up being a SubvertedTrope when it turns out that they both die in the final fight, and thus revealing the Ray's series is in fact a prequel.]]

* HeroicSacrifice: [[spoiler:Jax had to fuse with a critical Martin Stein to safely bring the latter back to Earth-1 and to the Legends' ''Waverider'', but this causes Jax to also go critical because of their link. Martin decides that he has to take Cisco's [[ChekhovsGun serum]] to sever the link and save Jax's life at the cost of his own.]]

** Dark Arrow mocks Oliver by claiming that caring for others makes you weak. But he clearly cares for [[spoiler:Tommy-X (whom he openly calls his best friend). He also cares for his wife, Overgirl, leading the invasion of Earth-1 so he can save her life, and is shattered when she dies.]]
** Overgirl believes that humans are inferior to her. [[spoiler:But that didn't stop her from marrying one.]]
* IfYoureSoEvilEatThisKitten: [[spoiler:Quentin-X]] asks a disguised Earth-1 Oliver to prove he's Oliver-X by asking him to shoot a bound up Felicity-X. Played with as this is disguised as a present for sadistic Oliver-X. [[spoiler:He fails. [[ItWorksBetterWithBullets And the gun wasn't loaded.]]]]

* InsultFriendlyFire: Kara reacts with a "Gross!" [[spoiler:after learning that her and Oliver's doppelgängers [[UnholyMatrimony are married]]]] only to quickly apologize to Oliver.
* InTheBack: Averted. Oliver has a perfect opportunity to shoot Dark Arrow in the back after [[spoiler:Overgirl explodes]], but can't go through with it. [[spoiler:When Dark Arrow turns to attack him, Oliver drops him then and there.]]
* IronicEcho: Dark Arrow laughs at [[IllKillYou a threat]] from Oliver, saying he's too weak to do it. Dark Arrow later says the exact thing [[spoiler:right before Oliver offs him with an arrow to the heart before he can retaliate.]]

** Overgirl revels in her strength, believing it makes her superior to others. [[spoiler:In the end, she is helpless to prevent her own death.]]

** [[spoiler:Tommy-X plays up the fact that his family is in constant danger due to the Third Reich. Oliver swears he will help protect him and his love ones from the Dark Arrow. Cue [[ILied Tommy's mocking laughter in a confused and pained Oliver's face]] before ingesting a CyanideCapsule, declaring his steadfast allegiance to the Führer.]]

* KryptoniteFactor: As per usual for a story with Kryptonians, it plays a part. Aside from [[spoiler:Earth-X's Metallo]], apparently Oliver has some...[[NoodleIncident somehow]].

* {{Leitmotif}}: All of the characters' themes are present and usually blended seamlessly together. In addition, the Flash's theme plays during the meeting between Barry and the awkward waitress who talks to him during his wedding, hinting that she is [[spoiler:Dawn Allen, their daughter from the future, or Dawn's own daughter, Jenni Ognats.]]

* LoveIsAWeakness: The New Reichsmen are strong proponents of this, which is why they are so disgusted by their Earth-1 counterparts, who are driven to fight to protect the ones they love. [[spoiler:It also makes them hypocritical -- the main motivation of Oliver-X's decision to invade Earth-1 is not to conquer it, but to save his wife, Kara-X. When she dies, he becomes distracted in his grief, and is killed by his counterpart for it.]]

** The whole cast when they learn the Earth-X invaders are [[spoiler:gathering materials for a neutron bomb.]]

* MirroredConfrontationShot: In part 2, between Oliver, Barry and Kara vs. their Earth-X counterparts (just as they unmasked themselves in front of them, conveniently enough) [[spoiler:and Eobard Thawne.]]

* MissionControl: Iris, Caitlin, Harry and Felicity choose to serve as this, with Curtis and Team Arrow following suit from Star City, [[spoiler:only for Team Arrow [[BigDamnHeroes to come to]] Heatwave and Killer Frost's aid against Dark Arrow.]]

** Overgirl's SuperpowerMeltdown; [[spoiler:Superman had a similar terminal condition from ''ComicBook/AllStarSuperman''.]]
** The awkward waitress at Barry and Iris' wedding is heavily implied to be [[spoiler:either Dawn Allen, their daughter from the future, or Dawn's own daughter, Jenni Ognats.]]
** [[spoiler:Citizen Cold/Earth-X Snart's goggles]] are the same design as they are in the comics.
** ComicBook/{{Supergirl}} taunting Overgirl to come out and fight her while hovering outside the window of the [[spoiler:Earth-X Waverider]] is intentionally styled after Superman's confrontation with Zod in ''Film/SupermanII'', down to an identical line.

* NiceJobFixingItVillain: [[spoiler:In Part 3, the Kommandant's idea of executing the captive heroes and another prisoner simultaneously seems to be his idea of hitting two birds with one stone, except he didn't really anticipate a fellow Freedom Fighter coming to the rescue of said prisoner? Because of this, the Freedom Fighters now have half a dozen new allies to help take down the New Reich. Especially jarring when the Kommandant was portrayed as virtually competent for the rest of the episode.]]

* NotHisSled: The opening scene of the event had the Freedom Fighters readying a portal, with the scientist in charge explicitly stating that this may be their last hope; it's implied they are finally planning to send an SOS to other Earths, just like how the heroes of Earth-X in the comics were also requesting aid. And then Dark Arrow arrives and takes out the resistance unit, claiming the portal for himself and his army. [[spoiler:At the end of the event, however, the Freedom Fighters ''do'' manage to get their new allies anyway, and conveniently find a way to open breaches to other Earths (specifically, Cisco) if they're ever in need of assistance again.]]

** Harry, when [[spoiler:Dark Arrow]] breaks into S.T.A.R. Labs.
** Kara, when the Earth-X version of [[spoiler:Metallo]] shows up.

* ThePsychoRangers: The Nazi leaders are the evil counterparts of the Arrowverse "Trinity": Overgirl for Kara, Dark Arrow for Oliver, and the Dark Flash for Barry, [[spoiler:who turns out to be actually Earth-1 Eobard Thawne.]]

** [[spoiler:Prometheus-X is Tommy Merlyn and the Dark Flash is actually [[HesBack Earth-1 Reverse-Flash]] working with the New Reichsmen just for kicks.]]

** When rescuing Kara, Iris tells her [[Franchise/TheTerminator "Come with us if you want to live."]] Who do they quickly run into? [[spoiler:Metallo]], who as a SkeleBot9000 looks like a de-fleshed Terminator (and is explicitly called that [[BrickJoke later]]).

* SkeleBot9000: [[spoiler:Similar to the classic comic look, Metallo-X looks like this.]]

** When Dinah and Cisco are taking cover from [[spoiler:Earth-X Metallo]], Cisco is more focused on Dinah's pop culture reference.

** Part of the FinalBattle in Part 4 sees Killer Frost, Amaya, and Zari board the [[spoiler:Earth-X Waverider]].
* SuperiorSuccessor: Overgirl certainly believes [[spoiler:her husband]] to be Hitler's in regards as the current Führer of the Third Reich.
* SuperpowerMeltdown: [[spoiler:One of the reasons for the invasion is because Overgirl is dying from being supercharged with solar energy, and needs Kara's heart as a replacement to save her. Without it, the charge builds until her body can no longer keep it at bay and she ''literally'' goes nuclear]].

* TerribleTrio: [[spoiler:Since Prometheus dies at the start of Part 2, Thawne, Overgirl and Dark Arrow form this.]]

* TimeyWimeyBall: [[spoiler:Thawne, possibly from some point in time when he was disguised as Wells, working with Earth-X. When called out on the oddity of this, he merely states "[[LampshadeHanging time travel's confusing]]".]]

** [[spoiler:Oliver-X is killed by his Earth-1 counterpart not long after his wife completes her SuperpowerMeltdown, goes nuclear, and blows up in the atmosphere]].
** [[spoiler:Professor Martin Stein, having been fatally shot, forces Jax to sever the connection between them so the latter may live, and joins his first partner Ronnie Raymond in death. [[WidowWoman Caitlin]] even asks, while burying Stein, if he could say a hello to Ronnie for her.]]

* ViolentlyProtectiveGirlfriend: Or wife in this case, [[spoiler:Overgirl does not take kindly to Reverse-Flash threatening her husband.]]

* WellIntentionedExtremist: [[spoiler:General Schott]] while [[JerkWithAHeartOfGold sympathetic]] to the Earth-1 refugees, still adamantly refuses to keep the warp gate back to Earth-1 standing long enough for them to return home. [[spoiler:At least, at first.]]

** Given the state of emergency Central City is in, you'd think someone on Team Flash would have tried contacting [[RubberMan Ralph Dibny]], particularly when Iris and Felicity [[spoiler:are trapped in Nazi-occupied S.T.A.R. Labs, after Dark Arrow dispatched of Heatwave, Killer Frost, Black Canary, Mr. Terrific and Wild Dog.]]

** Cisco goes comatose (but not too serious, they believe he'll eventually recover from it soon enough) during the first battle against the Earth-X invaders. The significance of creating this "absence" is only explained in Part 2, where [[spoiler:the heroes are now trapped in Earth-X. Surely, even if he's not completely 100%, Cisco could have easily broken them out.]]

* MeaningfulEcho: Kara sings "Running Home to You", as Iris walks down the aisle. The song Barry sang when he proposed to her.

* IfYoureSoEvilEatThisKitten: [[spoiler:Quentin-X]] asks a disguised Earth-1 Oliver to prove he's Oliver-X by asking him to shoot a bound up Felicity-X. Played with as this is disguised as a present for sadistic Oliver-X. [[spoiler:He fails. And the gun wasn't loaded.]]

* InTheBack: Averted. Oliver has a perfect opportunity to shoot Dark Arrow in the back after [[spoiler:Overgirl explodes]], but can't go through with it. [[spoiler:When Darkk Arrow turns to attack him, Oliver drops him then and there.]]

* EarlyBirdCameo: The Arrowverse's version of The Ray makes his debut in this story arc, and will be seen again in ''WesternAnimation/FreedomFightersTheRay''.

** Cisco and Wells use quark spheres to trick the Firestorm Matrix into thinking Martin and Jax are still linked, just as Cisco did in "The Flash Reborn" to trick the Speed Force into releasing Barry.
** Mick recalls having kidnapped Caitlin back in Season 1, to which he advises him not to try it again.

*** Leo lampshades this by [[NotSoSimilar admitting that's a terrible idea,]] and that he always has a plan, [[CrazyPrepared down to the last detail.]]

** The crossover upholds the Arrowverse tradition of cameos from former superhero television with [[Series/TheGreatestAmericanHero William Katt]] as the priest who gives Iris and Barry their vows moments before [[spoiler:[[DeathByCameo he's vaporized by Overgirl.]]]]
** Susanna Thompson, who plays Moira Queen, makes a surprise voiceover appearance as [[spoiler:Earth-X's Gideon]].

** When Oliver-X invades STAR labs, and give a lot of trouble to the heroes, the Team Arrow recruits arrive as reinforcement...[[spoiler: [[SubvertedTrope but don't end up faring any better]].]]

** Part 2: [[spoiler:Iris and Felicity are trapped in a Nazi-occupied S.T.A.R. Labs as they watch the invaders lock Team Arrow, Killer Frost and Heatwave in the pipeline, and the rest of the heroes find themselves in a concentration camp on Earth-X, with Kara's location unknown.]]

* EarnYourHappyEnding: Not exactly an ending per se, but after all the shit they've been through, and the many obstacles, including death itself, the two had to overcome, Barry and Iris can finally call each other [[HappilyMarried husband and wife.]]

* LiteralMetaphor: When Harry and Caitlin bring up that they can use technology on the Waverider to find out the location of the Earth-X invaders, Jax denies it because the Waverider is "in the Stone Age." He then clarifies that he means that [[TimeTravel literally]].

** A funnier version happens when the girls quickly search for an excuse as to why Kara's alien fingernails breaks the manicurist's blade.

** When the DEO is first trying to identify the Dominator Supergirl fights, one of Alex's guesses is [[SelfDemonstrating/Lobo Czarnian.]]

* VillainForgotToLevelGrind: Downplayed, but in the final battle, Barry is able to fight Reverse-Flash on equal footing, and win. In all their previous encounters (save for those that involved a younger, less experienced Thawne), Barry was sorely outclassed, but due to a combination of experience and a [[Recap/TheFlash2014S4E1TheFlashReborn recent upgrade to his speed]], he can finally match his nemesis move for move.

** After the Nazis have completely taken over STAR Labs, Felicity sends an S.O.S. to the rest of the Legends. [[spoiler:They only manage to arrive near the end of the event, but are a lot more helpful against the Nazis with Ray Palmer saving Kara's life.

* ThePsychoRangers: The Nazi leaders are the evil counterparts of the Arrowverse "Trinity": Overgirl for Kara, Dark Arrow for Oliver, and meanwhile the Dark Flash is Barry's fellow speedster nemesis Eobard Thawne.

* SerialEscalation: The first big multi-hero crossover (the fight against Vandal Savage) had 9 heroes and MissionControl backups involved fighting on the side of the good guys. The second against the Dominators had 17 ([[MyFriendsAndZoidberg including Mick]]). This one has 25, not counting most of the Earth-X resistance. [[RunningGag But including Mick.]]

* TakeThat: Before anyone realizes that the Nazis are from Earth-X, everyone wonders why anyone would want to follow an ideology that failed seventy years ago. Clearly a reference to the current rise of Neo-Nazis and fascist apologists, with a specific one in Jax uttering his disgust with Nazis with the quip [[UsefulNotes/DonaldTrump "Make America Aryan Again"]].

'''Harry:''' There's a ''53rd'' Earth and it's called Earth-X. Basically our Earth with one difference: the Nazis ''won'' the War.

* KryptoniteFactor: As per usual for a story with Kryptonians, it plays a part. Aside from [[spoiler:Earth-X's Metallo]], apparently Oliver has some... [[NoodleIncident somehow]].

** Half of the Legends apparently spent the majority of the event on a mission in the Stone Age. They make it back just in time to save everyone... and also just in time for Part 4, a.k.a. ''their'' Earth-X tie-in.

'''Oliver:''' ''[[[NotSoAboveItAll defensively]]]'' Just a quick reminder. SuperSpeed... I don't have it!

** Wally whisks Joe and Cecile out of Central City after the New Reich's attack... and doesn't appear again.

** Especially the case for Diggle, who as opposed to usual, was left out of the events of the crossover entirely save for the final scene where he's only brought in to marry Barry and Iris.