* AbilityOverAppearance:
** The producers had a choice between keeping Slade Wilson as an American, like in the comics, and casting Maori actor Creator/ManuBennett in the role. They took the second option and turned Slade into an Australian spy.
** Creator/StephenAmell is also a case of this - in the present day he looks mid-to-dark brunette as Oliver (like Stephen is in real life), but in flashbacks where he has longer hair and a beard both are clearly dirty-blond (making him resemble the comic's Oliver Queen a lot more). Because it would be hard to die his short-cropped hair (let alone his ''stubble''), and because Amell portrays the character so convincingly, most people treat this as AcceptableBreaksFromReality and are generally not bothered by it... Worth noting is that Oliver's ''probably'' supposed to have a shade of blond in the show as well (that simply looks darker in the present thanks to lighting and shortness), because both his parents are blond and Thea [[spoiler:is really Malcolm Merlyn's biological daughter, thus explaining her own brown hair.]] Further, Amell also has a larger frame compared to the comics' Ollie (who has toned arms but a smaller overall frame than heroes like Batman and Superman - his frame would be more in line with ''Series/{{Smallville}}'''s Justin Hartley in comparison), but overall few people have expressed displeasure with this.
** Creator/CaityLotz taking over for Jacqueline [=Mcinnes=] Wood as Sara Lance is also an example. Season 1 firmly established her as a tall, raven-haired woman and both of those traits became an important plot point for her family's arc late in that season. Caity Lotz's entire appearance is far different from Jacqueline [=Mcinnes=] Wood's, but her excellent portrayal of the character made the fans ignore and look past the major ContinuitySnarl caused by the recasting.
* ActorAllusion:
** At one time, Laurel snarked at Tommy if he's planning to take her to ''Film/MonteCarlo''.
** Creator/WillaHolland (Thea) is pretty much playing her character from ''{{Film/Legion}}'' - a rebellious teenage daughter to an upper-class family.
** Felicity having a DisappearedDad. Creator/EmilyBettRickards' role in Music/{{Nickelback}}'s music video [[https://www.youtube.com/watch?v=Nt2kM0TsubU&NR=1 "Never Gonna Be Alone"]] also has one (albeit in a more TearJerker way).
** Thea describes Roy Harper as 'Abercrombie-looking'. Guess which company his actor modeled for? Revisited in "Broken Dolls", where Sin also keeps calling him ''Abercrombie''. It becomes her AffectionateNickname for him.
** Barry mentions that [[ICantDance he can't dance]]. [[Series/{{Glee}} Some might disagree]].
** A flashback in "Heir to the Demon" reveals that Mrs Lance was a Professor. Creator/AlexKingston has played a Professor [[Series/DoctorWho before]].
** Tatsu is handy with katanas, just like Yukio, the character Creator/RilaFukushima played in ''Film/TheWolverine''. She's also tasked to "babysit" the WhiteMaleLead there, though this time she has her entire family helping her with the "job".
** The ''Series/{{Spartacus}}'' alumnae also get this.
*** Katrina Law's character is still an ArcherArchetype ActionGirl. This time though, ''she'' is the one [[GirlOnGirlIsHot who kisses a girl]].
*** As of Season 3 Episode 8, Creator/ManuBennett and Nick E. Tarbay's characters are [[spoiler: now cellmates. In ''Spartacus'', the gladiator quarters is very much like an "open prison"]], and their characters are bitter enemies.
*** Slade's manner of teaching Oliver how to fight is not unlike Doctore Oenomaus' teaching his own character, Crixus.
** Starting Season 3, Creator/BrandonRouth is [[Film/SupermanReturns once again]] flying around in a red and blue suit. In "Suicidal Tendencies", Oliver calls Ray "Supersuit", and Felicity calls his photo imaging tech "X-Ray vision". In "Broken Arrow", he fights Deathbolt, whose eye beams greatly resemble Franchise/{{Superman}}'s heat vision. He defeats him [[WesternAnimation/SupermanTheAnimatedSeries by using his hands to cover up the eye beams at point blank range, resulting in blowback.]]
** During her EarlyBirdCameo in Season 2, [[Series/TheFlash2014 Caitlin Snow]] had a scene where she has to run away from [[Film/FridayThe13Th2009 a blade wielding masked killer.]]
** Creator/NealMcDonough is playing a terrorist in a nice business suit who obtained special powers through implied sacrificial means. Are we sure he's not just playing [[Film/StreetFighterTheLegendOfChunLi M. Bison]] again?
*** He makes a joke about Malcom's hand getting cut off, after suffering this himself in ''Series/{{Justified}}''.
** Tom Amandes as the DeadpanSnarker {{Jerkass}} dad of a clever blonde woman in a Greg Berlanti show? [[Series/{{Everwood}} This rings a bell...]]
* ActorSharedBackground: Creator/NealMcDonough is in fact married to a woman named Ruvé.
* ApprovalOfGod: Creator/StephenAmell has "Meme Monday" on his Facebook page, where he reposts memes of the show that he finds funny. He's also done some bizarre one-offs, such as "Lightsaber Saturday" where he does the same sort of thing only with a specific theme.
* CastingGag:
** Paul Blackthorne [[Series/TheDresdenFiles as a detective]].
** Creator/KatieCassidy, a prominent "[[UsefulNotes/ScreamQueens Scream Queen]]" during the [[TurnOfTheMillennium 2000s]], plays a character who [[MakeMeWannaShout is renowned for being just that]]. The gag is reflected by the fact that majority of the actresses considered for the role (see below) during conceptualization were also "Scream Queens".
** Creator/NealMcDonough previously [[WesternAnimation/DCShowcaseGreenArrow played Green Arrow]]. He joins the show as the villain of the fourth season in an episode titled "Green Arrow." He'll also appear in the second annual {{Crossover}} with ''Series/TheFlash2014''. He also [[VideoGame/InjusticeGodsAmongUs previously voiced The Flash]].
** Kevin Alejandro is a man named Blood who was raised by AbusiveParents. [[Series/TrueBlood Nope, doesn't sound familiar at all.]]
** Cupid's actress, Amy Gumenick, and Creator/StephenAmell were [[https://en.wikipedia.org/wiki/Natalee_Holloway_(film) in a movie before]] where ''he'' played her character's alleged StalkerWithACrush.
** Creator/BrandonRouth's character is wearing a PowerArmor, hence he's now a ''[[StealthPun literal]]'' [[Franchise/{{Superman}} Man of Steel]].
* CreatorBacklash:
** Not regarding the show itself, but Creator/StephenAmell has quite happily voiced his displeasure over how the execs handle promoting the show, namely that the posters highlight the ensemble cast, but leave out Paul Blackthorne and Creator/SusannaThompson. He similarly criticized WB for announcing plans for a ''Flash'' film and a new actor the day after ''The Flash'' posted strong second-week ratings, showing true staying power, feeling it undercut both the show and Creator/GrantGustin.
** Creator/CaityLotz was understandably not pleased with her character's treatment in Season 3, being [[spoiler:killed off in the premiere and then strung along for more appearances anyway]]. She did two (as a fake voice, and a hallucination). However, she was pleased to be resurrected in the fourth season of Arrow and move on to ''Series/LegendsOfTomorrow''.
** Marc Guggenheim and co. admitted "[they] fucked up" with how they forgot about Roy at the end of the Arrow vs. Atom fight in "Suicidal Tendencies". They also wished, in hindsight, to have Oliver [[spoiler:join the League earlier to allow more time to play around with "Al Sah-him"]].
** Creator/EmilyBettRickards admitted she wasn't happy about the writers playing down her character's comedic side in exchange for angst during Season 3, and said she looked forward to having funny and happy Felicity back in Season 4.
** Though he doesn't express regret about the part, Creator/ManuBennett of all people [[http://comicbook.com/2015/04/04/manu-bennett-thinks-arrow-took-deathstroke-in-the-wrong-directio/ feels that the show didn't quite do his character justice]], especially with his Season 3 appearance wherein he suffers BadassDecay [[spoiler:being beaten by Oliver and Thea alone]].
*** Comments Bennett has made on social media also seem to indicate he shares the fandom's sentiments regarding the show's SeasonalRot / RomanticPlotTumor and no longer desires to be part of the show, a factor that has likely contributed to Slade's LongBusTrip.
** Both Creator/WillaHolland and Creator/EmilyBettRickards (as well as former FakeGuestStar Creator/CaityLotz) are not fans of the decision to [[spoiler: kill off Laurel]] in Season 4 and have expressed it in cons.
* CreatorsFavoriteEpisode: [[https://mobile.twitter.com/niklauszj/status/751453717048721408 Stephen Amell's favorite episodes]] are the Pilot, "Year's End", "Three Ghosts", "The Promise" and "The Climb".
* TheDanza: In the Japanese dub, Creator/KazukiYao voices '''Yao''' Fei.
* DawsonCasting: Averted for the most part, as most of the young adult characters are portrayed by actors 2-4 years older and so convincingly pass themselves as those ages; Katie Cassidy (Laurel Lance) and Emily Bett Rickards (Felicity Smoak) are in fact ''younger'' than their respective characters. The flashbacks, on the other hand, cannot avoid this pitfall because they also function in chronological order but are always 5 years behind the present-day scenes: 23-year-old Willa Holland stands out when portraying a 15-year-old Thea Queen in Season 3's "The Return".
* DearNegativeReader: Stephen Amell commented on the backlash to the ''Olicity'' pairing on Facebook.
* DuelingShows: With ''Series/AgentsOfShield'', as both series fall under the long-standing Creator/DCComics[=/=]Creator/MarvelComics rivalry.
* DyeingForYourArt: Katie Cassidy lost a significant amount of weight during the production of season two, to better convey Laurel's addictions to painkillers and alcohol. The following season, Katie bulked up in the gym as Laurel suited up as Black Canary.
* EditedForSyndication: On Netflix, Oliver's OpeningNarration and the PreviouslyOn for Season 3 have been cut for some reason.
* ExiledFromContinuity:
** Certain big-name characters such as Franchise/{{Superman}} and Franchise/{{Batman}} cannot appear in this universe as WB has reserved them for exclusive use within the [[Franchise/DCCinematicUniverse emerging movie franchise]].
** Despite him already appearing, ComicBook/{{Deadshot}} was made unavailable for the show for movie franchise reasons, after Creator/WillSmith was confirmed to be playing him in ''Film/SuicideSquad2016''. [[spoiler:It was explicitly confirmed that this is why he was killed off in season 3 episode "Suicidal Tendencies".]]
** Several other characters were made off-limits as well, including Harley Quinn and Ted Kord (as mentioned below).
** As with Deadshot, [[spoiler: Amanda Waller was [[BoomHeadshot taken off the show]] due to the character's role in the same film]].
* FakeMixedRace: American of Indian heritage Janina Gavankar plays the possibly mixed race (judging from the surname) [=McKenna=] Hall.
* FakeNationality:
** Creator/StephenAmell, the Arrow himself, is Canadian.
** As is Creator/EmilyBettRickards (Felicity Smoak).
** As is Jacqueline [=MacIness=] Woods ([[TheOtherDarrin the original]] Sara[[ContinuitySnarl h]] Lance).
** Creator/ManuBennett ([[AussiesWithArtillery ASIS commando]] Slade Wilson) is a New Zealander.
** Jessica de Gouw (ComicBook/{{Huntress}}) is Australian.
** Paul Blackthorne (Quentin), Creator/JohnBarrowman (Malcolm) and Creator/AlexKingston (Dinah) are all British, though all three have extensive US experience, with Barrowman, who normally speaks with an American accent as he was raised in the US, holding dual nationality.
** American of German and Scotch-Irish descent Creator/SummerGlau plays Isabel Rochev, a Russian who was later naturalized as an American.
** Speaking of Aussies, Digger Harkness is Australian in the comics, but here played by Lebanese-American NickTarabay.
** Eugene Lipinski (Alexei) is from England, playing a Russian character.
** The late Darren Shahlavi was Iranian-English, but played the American Constantine Drakon.
* FanNickname:
** Fans have started calling [[http://www.greenarrowtv.com/first-look-at-arrows-huntress/12378 The Huntress]] of this show "ComicBook/{{Catwoman}} with a Crossbow."
** Diggle's unborn child has already been named [[Anime/{{Pokemon}} Diglett.]]
** Sally the Salmon Ladder.
** Deathstroke and Brother Blood's Mirikuru-empowered minions are referred to as the Deathstrokes, or some variant of, by many fans, though aren't actually named in the show itself. One of the alternative names is 'The Blood Cult'.
** Laurel has been given nicknames such as {{Blackmail}} Canary (due to her habit to use blackmail on Kate Spencer during the latter half of Season 2) or Fakanary (thanks to some people considering that Sara is the show's true ComicBook/BlackCanary) and now Buckles (thanks to the endless straps on her Black Canary costume).
** Creator/StephenAmell himself has been nicknamed 'Captain Amell' or 'The Captain' by Olicity supporters, thanks to his enthusiasm for Oliver and Felicity's relationship. Other parts of the fandom are now picking it up out of pure affection.
** [[TheVerse The universe or continuity]] itself which also includes Series/TheFlash2014 has been nicknamed "the Arrowverse", in similar vein to the "[[Film/TheDarkKnightSaga Nolanverse]]".
*** Both "the DCCWU" and the "DCW" are also used.
** Brother Eye, a hacktivist group using a flaming eye for a symbol, is [[TheLordOfTheRings "Sauron]][[{{Anonymous}} ymous"]]
** [[spoiler: Ra's Amell]] for Oliver [[spoiler: wearing the League of Assassins attire that was [[TrailersAlwaysSpoil spoiled by ''Flash's'' PaleyFest trailer]]]].
** In some countries, Quentin Lance and (his ex-wife) Dinah Drake are called "Papa Canary" and "Mama Canary" for obvious reasons.
** The PowerTrio of Oliver, Diggle and Felicity have been labelled 'Original Team Arrow' - a lot of the cast have picked it up as well and they writers made the phrase canon in Season 4.
* FollowTheLeader: The success of ''Arrow'' not only spawned a [[Series/TheFlash2014 spin-off]], but prompted [[Series/{{Gotham}} Fox]] and [[Series/{{Constantine}} NBC]] to launch their own shows based on Creator/DCComics characters, and Creator/{{Netflix}} to partner with Marvel on a series of shows about street level heroes in the Franchise/MarvelCinematicUniverse. It can even be argued that ''Arrow'''s success is what led to NBC finally going ahead with the revival of ''Series/{{Heroes}}''. And with ''Series/{{Supergirl 2015}}'' coming to CBS, we'll have gone from no comic-book shows to one on every single broadcast network.
* FunWithSubtitles: A minor example, but the DVDs on Season 1 labels Oliver's dialogue when he's investigating as coming from "Arrow" or "Green Arrow", regardless of whether he's in costume, in his bike jacket and helmet or in ''civilian attire''. He didn't even take either names until season 2 and 4, respectively.
* HeyItsThatPlace: The house that is used for the Queen Mansion is [[http://en.wikipedia.org/wiki/Hatley_Park_National_Historic_Site Hatley Castle]] in Victoria, British Columbia. It was used for the Luthor Mansion on ''Series/{{Smallville}}'' and Xavier's school in the ''Film/XMen'' movies.
* IKnewIt:
** Sebastian Blood is [[spoiler:Brother Blood]].
** [[spoiler:Sara Lance survived [[NeverFoundTheBody the sinking of the Queen's Gambit]]. Her being Black Canary was also a popular crack-theory not even five episodes into season 1.]]
** A number of people suggested that due to her brown hair not being a trait inherited from two blonde parents, [[spoiler: Thea wasn't Robert and Moira Queen's daughter. It was revealed in "State v. Queen" that Thea was conceived after an affair between Moira and Malcolm Merlyn]].
** [[spoiler: Malcolm is BackFromTheDead. Okay, technically he never died in the first place, but the point stands.]]
** As soon as [[spoiler:Sara]] asked Oliver "What happened to [[spoiler:Slade]]?" without mentioning [[spoiler:Shado]], people correctly assumed she was killed.
** [[spoiler:Slade's return.]] Given the character's popularity, [[LikeYouWouldReallyDoIt most fans knew he wouldn't be killed like he was]]. Also, since the character is known for being a ''villain'', as soon as they mentioned [[spoiler:what Ivo was looking for and what Brother Blood was doing, many worked out he would be used on Slade and that he was the BigBad]] well ahead of the reveal.
** Malcolm Merlyn being involved in [[spoiler:Sara's death]] in Season 3; not as obvious and many had their doubts, but some still expected TheReveal just the same.
** [[spoiler:Akio, Maseo and Tatu's son,]] dies.
** When Marc Guggenheim revealed a second wedding in Season 3, a lot of people accurately predicted that it would be between [[spoiler:Oliver and Nyssa]].
** Thea Dearden Queen being the show's version of [[spoiler: Mia Dearden was accurately predicted by majority of the fans as early as the pilot]].
** Pretty much everyone figured out that Nyssa will be the one who will complete Laurel's training to be Black Canary the moment [[spoiler: Sara [[DeathIsCheap dies]] in the Season 3 premiere]].
** A lot a people figured out that the Calculator was [[spoiler:Felicity's father]].
* IronyAsSheIsCast: It's worth noting that Paul Blackthorne's best-known role is magician Harry Dresden, and he plays a cop. John Barrowman's most famous role is him playing a sort of secret agent-slash-cop, and he plays a man whose codename is "Magician".
* IWantYouToMeetAnOldFriendOfMine:
** It's been a RunningGag among ''Series/{{Spartacus}}'' fans on whose alumnae will appear next on the show, or on ''Series/TheFlash2014'' for that matter. [[note]]Creator/ManuBennett, Cynthia Addai-Robinson, Katrina Law and Nick Tarabay here, and Liam [=McIntyre=] on ''Series/TheFlash2014''.[[/note]]
** Much like ''Series/{{Spartacus}}'', the show and its SpinOff have a knack on casting ''Series/PrisonBreak'' alumnae. [[note]]Creator/RobertKnepper and Creator/PeterStormare here, Creator/WentworthMiller and Dominic Purcell on ''Series/TheFlash2014''.[[/note]]
** The ''Series/{{Firefly}}'' alumnae are also prominent. Then again, the cast are known for being one of, if not, ''the'' most prominent members of Creator/DCComics' ProductionPosse. [[note]]Creator/SeanMaher and Creator/SummerGlau here, Creator/MorenaBaccarin, the voice of Gideon on ''Series/TheFlash2014'', and Creator/JewelStaite on ''Series/LegendsOfTomorrow''.[[/note]].
** ''Series/{{Glee}}'' alums are also prominent. [[note]]Bex Taylor-Klaus, Charlotte Ross and Nolan Funk here, Creator/GrantGustin and Victor Garber on ''Series/TheFlash2014''.[[/note]]
** Creator/StephenAmell and Janina Gavankar were both on ''Series/TheVampireDiaries''. [[note]]Ditto Creator/RickCosnett and Creator/MaleseJow on ''Series/TheFlash2014''.[[/note]]
** Colin Salmon, Creator/AlexKingston, and Creator/JohnBarrowman were all on ''Series/DoctorWho'', with the former two debuting in the same ''Who'' episode. [[note]]Creator/ArthurDarvill will be Rip Hunter in ''Series/LegendsOfTomorrow''[[/note]] Somewhat subverted in Barrowman's case, as he never acted with the other two before ''Arrow''.
** Jacqueline [=McInnes=] Wood and Emma were previously on ''Film/FinalDestination5'' together. [[note]] Creator/TonyTodd, the voice of Zoom on ''Series/TheFlash2014'', as well and Shantel [=VanSanten=], who plays Patty Spivot, were also alumnae of the ''Franchise/FinalDestination'' film series[[/note]].
** Creator/KatieCassidy and Creator/WillaHolland were {{Recurring Character}}s on ''Series/GossipGirl''.
* RealLife/MeanCharacterNiceActor:
** Creator/JohnBarrowman as Malcolm Merlyn. Hold most of the [[AffablyEvil mean]], though. He has said it's fun to play a bad guy for a change.
** Oliver Queen, at least early on, was cold, distant, and secretive. Creator/StephenAmell, on the other hand, is incredibly friendly and interactive with fans.
** Nyssa al Ghul is a rather cold, merciless assassin loyal to her father, but Katrina Law is anything but and is very friendly and talkative to her fans.
* NoStuntDouble: ZigZagged - Creator/StephenAmell does as much of his own stunts as he's allowed, including the infamous salmon ladder which Amell can pull off in real life, with some of the more complicated[=/=]dangerous stuff being done by a stunt double. Same goes for Creator/CaityLotz.
* OneOfUs: Head writers Guggenheim and Kreisberg are big comic fans and love continuity gags.
* TheOtherDarrin: Creator/CaityLotz as Sara Lance, replacing Jacqueline [=MacInnes=] Wood from the Pilot. There's even a FlashbackWithTheOtherDarrin.
* TheOtherMarty: Devon Aoki was set to play Tatsu Yamashiro in Season 3. However, she dropped out during filming and her scenes were re-shot with Creator/RilaFukushima in the role.
* ThePeteBest: Creator/CaityLotz is much more remembered as Sara Lance than Sara's original actress, Jacqueline [=MacInnes=] Wood. Notable because their differing depictions look ''nothing'' alike, yet the fandom is quite happy to [[CanonDiscontinuity blot Wood's dark-haired iteration of Sara]] [[FanonDiscontinuity out of their collective memory]].
* PlayingAgainstType:
** Before this series, Creator/StephenAmell was frequently cast as a villain or/and TheRival.
** The [[IceQueen cold-hearted]] Isabel Rochev is well outside of Creator/SummerGlau's usual repertoire, even moreso [[spoiler:now that it's known she's a flat-out villain]].
** The [[MadBomber bomb-happy]], [[StrawNihilist nihilistic]] Shrapnel is a far cry from Creator/SeanMaher's previous roles.
** Seth Gabel, famous for his role as [[TheStoic stoic]] Lincoln Lee in ''Series/{{Fringe}}'', plays [[EvilIsHammy The Count]], who rarely leaves [[ChewingTheScenery scenery uneaten]].
* PlayingGertrude:
** Creator/JohnBarrowman, playing Malcolm Merlyn, and Colin Donnell, playing his son, are only 15 years apart in age - Barrowman, born 1967, is about 7 years younger than Malcolm (b. 1960). At times they look more like brothers than father and son, which is further fuelled by Colin Donnell's own DawsonCasting (being two-and-a-half years older than his character). [[AllThereInTheManual Supplementary materials]] then reveals that he had Tommy at 19.
** To a lesser extent, Paul Blackthorne as Quentin Lance - the actor is canonically over 6 years younger than his character (Lance is born January 1963, Blackthorne in March 1969), and this stands out when acting against his on-screen wife Alex Kingston (born March, 1963).
** Both Creator/KatieCassidy (b. 1986) and Creator/EmilyBettRickards (b. 1991, actually the youngest of the cast) are a few years younger than their respective characters Laurel Lance (b. 1985) and Felicity Smoak (b. 1989).
* PlayingTheirOwnTwin: [[spoiler: Celina Jade as Shado and her twin sister Mei.]]
* ProductionPosse: Creator/PaulBlackthorne, Creator/ByronMann, Creator/KellyHu, Creator/SummerGlau, Creator/MichaelJaiWhite, Creator/SeanMaher, Creator/PeterStormare, Creator/BrandonRouth, Creator/MarcSinger and Creator/NealMcDonough were all Creator/DCComics adaptation veterans.
* ProductPlacement:
** For Windows 8 and Windows Phone, everywhere.
** All of the laptops are made by Asus.
* RealLifeWritesThePlot [=/=] TheCastShowoff: [[Creator/SummerGlau Summer Glau's]] character, Isabel Rochev, was not initially going to be a villain, rather a red herring. However, Summer was dissatisfied about being in a superhero series without getting in on the action, so Isabel Rochev became the Ravager.
* RealitySubtext:
** Much like Laurel, Creator/KatieCassidy has a father with drinking problems.
** Much like Thea, Creator/WillaHolland's mother is a SerialSpouse.
* RoleReprisal: Played with in the Japanese dub, as Creator/SanaeKobayashi also voiced the Dinah Laurel Lance version of the ComicBook/BlackCanary in the short-lived ''Series/BirdsOfPrey'' TV Series.
* RelationshipVoiceActor: Somebody on ''Arrow'' must '''really''' have liked ''Series/{{Spartacus}}'', no less than three actors from that show have shown up. Creator/ManuBennett, Cynthia Addai-Robinson, Katrina Law, and now Nick Tarabay all appeared on ''Spartacus'' before moving here (Liam [=McIntyre=] will also be appearing on ''Series/TheFlash2014''). Especially interesting is the fact that, unlike [[OnlySoManyCanadianActors other examples of actor-overlap,]] ''Spartacus'' was filmed half a world away in New Zealand.
* ScrewedByTheLawyers: The agreement to bring Series/{{Constantine}} on the show in Season 4 stated his appearance was a one time deal. This is lampshaded later when Thea asks why Ollie doesn't ask Constantine for help, only for him to reply that he's in Hell. Literally.
* ThoseTwoActors:
** Sadly averted as the above mentioned Sean Maher and Summer Glau ''played brother and sister'' in ''{{Series/Firefly}}'' but never even meet here.
** Creator/JohnBarrowman and Creator/AlexKingston both have recurring roles on ''Series/DoctorWho,'' though their characters on that show (Jack Harkness and River Song) never met. The announcement of Kingston's appearance here led to excitement that Jack and River might ''finally'' meet, but alas, the two actors ''still'' haven't appeared on-screen together.
* ThrowItIn: Every time that Ra's refers to Oliver as "boy", it's because Matt Nable went off-script. The producers left it in because they felt it worked with the character.
* WhatCouldHaveBeen:
** Justin Hartley, ''Series/{{Smallville}}''[='s=] ComicBook/GreenArrow, was considered to reprise his role back when the show was still being pitched. The higher-ups then decided that his rendition won't fit the DarkerAndEdgier tone of the series and amicably parted ways. During this time, former Black Canaries [[Series/{{Smallville}} Alaina Huffman]] and [[Series/BirdsOfPrey Rachel Skarsten]] were also considered to reprise their roles as his female lead.
** Creator/BlakeLively, Hilarie Burton, Creator/KatherineIsabelle, Shantel [=VanSanten=], Creator/RachaelTaylor, Minka Kelly, Creator/AlexandraBreckenridge, Creator/MaggieGrace and Creator/BrittanySnow were some of the names considered to play Laurel when the show was still being conceptualized. [=VanSanten=] was eventually cast as Patty Spivot on ''Series/TheFlash2014'' during its second season.
** Creator/LaurenCohan was the top choice to play Helena Bertinelli but is already committed to ''Series/TheWalkingDead'' when production began. Janet Montgomery, Creator/ShelleyHennig, Jessica Szohr and Anna Skellern were also considered.
** Mr. Blank was originally supposed to be the DC Comics villain Onomatopoeia. However, as Onomatopoeia only speaks in, well, [[ExactlyWhatItSaysOnTheTin onomatopoeia]], they couldn't make it work without him coming across as mentally disabled (since sound effects sound far different in real life compared to comic books).
** [[spoiler: Malcolm was originally considered to be Oliver's actual father. The showrunners ultimately decided against it since it's too [[Franchise/StarWars "Darth Vader and Luke"]] so they gave the StoryArc to Thea instead. Still, this was given a DiscontinuityNod in the Season 3 finale when Malcolm tells Oliver that he always viewed him "as a son".]]
** The twentieth episode of Season Two was originally going to be a BackDoorPilot for a potential spin-off focusing on Franchise/TheFlash. Based on both the strength of Creator/GrantGustin's portrayal of Barry Allen in "[[Recap/ArrowS2E8TheScientist The Scientist]]" and "[[Recap/ArrowS2E9ThreeGhosts Three Ghosts]]" and the fact that using the twentieth episode as a BackDoorPilot would interrupt the show's momentum as it built up to the season finale, the decision was made to make it a standalone pilot.
** [[spoiler: In early drafts of Season Two, Sara was originally going to take the role of Ravager, but eventually ended up as the [[ComicBook/BlackCanary Canary]]. Instead, the role of Ravager was given to Isabel Rochev]].
** The character who was going to buy out Queen Consolidated was originally going to be [[ComicBook/BlueBeetle Ted Kord]], a character whose existence was already implied through the appearance of Kord Industries. However, DC enacted an embargo on him due to "other plans", so the creators instead went with [[ComicBook/TheAtom Ray Palmer]]. This means that [[spoiler:the A.T.O.M. suit functions more like the Blue Beetle or Iron Man suits than it does its comic counterpart]]. This received an amusing DevelopmentGag the following season, when the team needs to steal a piece of tech from Kordís company to bring Ray back to normal size.
** Before Matt Nable was cast, Creator/LiamNeeson said he'd play the show's version of Ra's Al-Ghul "in a heartbeat". WordOfGod states that after learning this, the network approached Neeson on the off chance he had the time, but they were unable to reconcile their schedules.
** There were plans to use ComicBook/HarleyQuinn past her initial unnamed cameo, but WB/DC put the kibosh on this after the ''Film/SuicideSquad2016'' movie was greenlit. Presumably this was due to the same reason shows like ''Series/{{Smallville}}'' and ''WesternAnimation/JusticeLeagueUnlimited'' were [[ExiledFromContinuity barred from using certain characters who were being highlighted in movies at the time]]. Willa Holland later commented on this, confirming that had Harley been allowed, she would have played a significant role in Season 4.
** Season 3 Episode 5 is supposed to be titled "Oracle", but ComicBook/{{Batgirl}} was also ExiledFromContinuity, hence why it's titled "The Secret Origins of Felicity Smoak" instead.
** A.R.G.U.S. and the Suicide Squad were originally planned to be a major part of Season 3 but was scrapped by ExecutiveMeddling.
* TheWikiRule: [[http://arrow.wikia.com/wiki/Arrow_Wiki Naturally]].
* WritingByTheSeatOfYourPants: The flashforward to the grave at the start of Season 4 was made with no idea who was in it.
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