!! Fridge pages are Administrivia/SpoilersOff, so all spoilers were removed and all examples folderized. Proceed with caution. Administrivia/YouHaveBeenWarned
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[[folder:Fridge Brilliance]]
* The Foundation X plot, and the series itself, was left hanging to follow ''Double'''s FilmNoir theme. Old [[Creator/RaymondChandler mystery works]] would have many questions unanswered intentionally, and would be [[BittersweetEnding bittersweet]] at best.
** In addition, Wakana served as the FemmeFatale for Shotaro and in the end chose to sacrifice her own life to bring back Ratio/Philip. Similar to most noir fiction where the detective [[DidNotGetTheGirl losing the one woman he had feelings for]].
* Why is the Maximum slot on the right side of Double when most of the time it's for the Joker Memory, a left-sided memory? To discourage Shotaro from pulling a Twin Maximum Drive like he did in "The D Was Seen".
* Double (W) becoming Xtreme (X) while fighting the Beast (B) Dopant. The show's theme is called W-B-X.
** Alternately, Double ('''W''') + Xtreme Memory ('''B'''ird) = '''X'''treme.
* W letting go of half itself (i.e., Philip disappearing) after destroying Utopia (U).
* Shotaro's favored Memory, [[color:purple:Joker]], is said to possess the inherent power of the "trump card". Why should this be considered PersonalityPowers? Shotaro is actually the ''wild'' card, being the outlier in both {{The Chessmaster}}s' plans. What's the wild card in most card games? '''Joker'''. Being the metaphorical Joker is what ''makes'' Shotaro the trump card, as his [[{{Determinator}} sheer determination and devotion to]] [[TrueCompanions his friends]] allowed him to pull off the impossible and shake off the paralyzing fear inflicted upon him by Terror and defeat Utopia single-handedly without transforming, things Shroud's chosen warrior (Ryu) couldn't even do.
** This also extends to the movie: Daido assumed that Shotaro was out of the picture without Phillip or Double, only for him to receive the Lost Driver from Sokichi, gain the T2 Joker thanks to his affinity for its powers, and [[StormingTheCastle storm the castle]] in order to rescue his partner and protect his city.
* Philip's favored Memory, [[color:green:Cyclone]]. The two people capable of accessing the Gaia Library are Philip and Wakana. Wakana's signature Memory, Claydoll, represents [[DishingOutDirt the power of the earth]]. The [[color:green:Cyclone]] Memory represents the exact opposite, namely the power of the sky.
** All three of Philip's base Memories can be associated with the sky. [[color:gold:Luna]] obviously represents the Moon, while [[color:red:Heat]] represents the Sun (compare with Magma, a Memory with [[PlayingWithFire similar powers]] that draws its strength from the heat of ''the earth'').
* Xtreme may look like a silly way to spell extreme but it makes sense when you realize that [=CycloneJokerXtreme=] is the evolution of Double and X is the letter after W.
** It's also a punny name, based off Double's Cyclone Joker finisher, Joker E''xtreme''.
** Xtreme is read in Japanese as ''Ekusutorimu'', which contains the Japanese word for bird (''tori''), hence the Xtreme Memory's bird shape.
** The same logic applies to Accel Booster: B is the letter after A.
* Why is the Prism memory in [=CycloneJokerXtreme=]'s arsenal? Because it allows Double to combine the colorful memories for powerful attacks.
* Why is Mick the cat Ryubee's most trusted hitman? Because as a pet, he is totally loyal to his master unlike the rest of the family and Isaka.
* Claydoll's MagikarpPower may seem like it came out of nowhere, but it's actually a brilliant use of MeaningfulName. ''Gaia'' is the Greek Goddess of Earth. Taken 100% literally, a ''Clay Doll'' is a human figure made out of earth. In other words, Claydoll represents the power to make man one with the earth, turning the user into a literal Gaia.
* From "L on the Lips", Jimmy's "Spik" singing style tends to be pronounced like "speak", which helps to explain how he still manages to win the judges' respect in round 3 despite the cacophony. Yes: he wasn't singing, he was ''speaking'' to them.
* ''Movie Wars Core'' reveals that Narumi Sokichi was not only a Kamen Rider but had his own heavy equipment like the [=SkullGarry=] on hand. Clearly the detective agency's ElaborateUndergroundBase was built ''well before'' Begins Night, and not within the year between that and ep. 1.
** ''Message For Double'' confirms this, as Shroud did provide Sokichi with said underground base even before he assumed the identity of Skull.
* Isaka absorbed a huge number of Gaia Memories into his body, something that ''should'' be impossible. However, his Weather Memory was apparently used to prevent this (somehow keeping the others in check). All the powers he used were weather-like in nature, so it makes sense. When the Weather Memory finally broke, he was suddenly consumed by Living Connectors. Without the Weather Memory to keep them in check, the Gaia Memories he absorbed killed him.
* From ''Movie Wars Core'', the Spider Dopant's special ability caused the victim to inadvertently kill the person they loved the most. A common term for someone who kills their lover is '''BlackWidow'''.
* At first, Kamen Rider Eternal's rather somber, sad theme seems to not fit him very well. Then it's revealed later that he's actually a FallenHero with a tragic past, one that the song fits very well.
* How come they reuse the Dopant Memories from the beginning of the show in Episode 49 and in one of the spin-offs? Because there's no one to make more Gaia Memories, there's no way to make new ones (since the Sonozaki mansion collapsed onto the area where Gaia Memories are made), and the police began cracking down on Memories some time after the Sonozaki downfall. So you can't have a unique Memory unless you happen to have said Gaia Memory ''before'' the crackdown (like the Commander Dopant); find a rare one ''post-''crackdown (like the Energy Dopant); or, if you don't have either one, you would opt for one of the ''many'' mass-produced Memories, which happen to be the ones seen in the beginning.
* Why does [=CycloneJokerXtreme=] wield the Prism Bicker as their ultimate weapon? Because it's a [[BifurcatedWeapon two-in-one weapon]] for a [[SharingABody two-in-one]] Franchise/KamenRider!
** Moreover, unlike most {{Bifurcated Weapon}}s the Prism Bicker's component parts are completely different from one another. The [[InfinityPlusOneSword Prism Sword]] and [[LuckilyMyShieldWillProtectMe Bicker Shield]] both have their own special abilities, but it's only when they're combined that their true power emerges; just like how Shotaro's and Phillip's different personalities combine to form a Rider that's more than the sum of its parts.
** The weapons can even be related to each character:
*** Shotaro does most of the fighting for the pair, so he gets a warrior's weapon, the Prism Sword, which is always wielded in the ''right'' hand.
*** Phillip's special ability is the reason Double can use two Memories at once, so he gets a weapon which can combine the powers of up to four Memories; the Bicker Shield, which is always held in the ''left'' hand.
* Why is a Dopant that can shapeshift into any person called the Dummy Dopant? It starts with a ''D''. He's supposed to be an EvilCounterpart to Series/KamenRiderDecade.
** Another reason is because a Dummy, or a mannequin, usually wears tons of different clothes made for different people. Or to put an old saying, "going a day in someone else's shoes".
* The way the episodes are numbered makes for a clever development. The odd numbers start off the case (as in something isn't right) and the even numbers end the case (as in it's now fixed).
* What were those Core Medals doing on the Foundation's databanks if they were sealed inside the Greeed? They were actually the King's Core Medals that were owned by Kougami.
* The Cyclone Dopant has that huge yellow rider-esque eye. When you find out who their relationship with Daidou Katsumi, a.k.a. Kamen Rider Eternal, it makes so much sense! [[FamilyEyeResemblance He has his mother's eyes!]]
* It is possible that every single thing done by Shroud was to prepare Philip and Ryu for [=CycloneAccelXtreme=]. Philip's body was weak and he did not know how to fight, so he is paired with someone who can fight and look after him (possibly meant to be Sokichi). In theory, CAX runs on rage, and so Fang uses Philip's body and sends him berserk so he can learn to deal with this rage in combat first. Ryu is given Trial to get him used to increased power, and the Engine Blade because he will use a sword as CAX. The Prism Bicker takes up 4 memories, despite Philip and Shotaro having six because out of the normal shape ones they would have 4 between Philip and Ryu. Last, Philip's memories can be considered to match up with the modes of the Engine Blade; Cyclone=Jet, Luna=Electric and Heat=Steam. CAX was not just the latest idea Shroud had. She had been planning for it from when she first met Ryu and hired Sokichi.
** As for why she doesn't say [=FangAccelXtreme=] is the strongest form of Double, despite the Fang memory being more powerful than the Cyclone memory? As we see in TheMovie, the T2 Accel memory doesn't go to Ryu Terui--suggesting that while his synchronization rate with the regular Accel memory might be strong enough for regular [=FangAccel=] or [=CycloneAccelXtreme=], it's ''not'' strong enough for [=FangAccelXtreme=].
* The ''[[Series/KamenRiderDenO Cho Den-O Trilogy]]'' comprises Episodes Red, Blue and Yellow, starting at the same time that Accel Trial debuted. So Accel, already red, turns blue, referencing two parts of the trilogy--so what about Yellow? Well, Accel in yellow was teased for some time since he turned yellow before going Trial for no real reason (until ''Double Returns: Accel''), which is quite appropriate as Episode Yellow is about [[Series/KamenRiderDecade Kaito/Diend]], who ISN'T EVEN YELLOW, and ends with Kaito [[{{Troll}} going right back to his old ways]], with none of the resolution in Red and Blue.
* In ''Double Forever'', the T2 Ice Age and Violence Dopants turning out to be Santa-chan and Watcherman respectively makes a funny kind of sense if you think about it - which season is Santa always connected to? ''The winter''. And in the previous movie event, ''Movie Wars 2010'', Watcherman brings up his taste for chicken breast early on, which seems like a throwaway comment...until you notice that Violence Dopant ''has the most massive pectorals of 'em all.''
* It's been stated back in [[Recap/KamenRiderDoubleE3E4DontLayAFingerOnM Don't Lay A Finger On M]] that Phillip can gamble effectively to the point where he and Shotaro can clean the house. So how come they're wasting their time with missing pet cases and not gambling? Well, finding missing cats is a really simple task when you have a know-it-all who can just look up where they're at with about three keywords. And it's much safer and moral than gambling is.
* The side characters come in pairs: 2 teenage girl informants (Queen and Elizabeth), 2 middle-age guy informants (Watcherman and Santa-chan), 2 antagonist sisters (Wakana and Saeko). One could even count Akiko and Terui and Shroud and Ryubee as pairs.
** Going further with this, the two Movie Riders (discounting Joker) are paired as well, as they both serve to be foils for the heroes, or rather, their fulfillment of goals. Narumi's everything Shotaro wanted to be, but with the cost of having to run away from the people he loves, while Daido, brought up in the same manner of Phillip (right down to his mom cribbing notes off how Phillip was revived) had something Phillip wanted (a family in both [[TrueCompanions figurative]] and literal manners), but treated it more like a toy than anything else.
* Despite how powerful he was, Terror felt out of place as a Gaia Memory. "Terror" sounds a lot like "Terra" when pronounced in Japanese. Terra, another word for earth.
** Wakana's [=ClayDoll=] Gaia Memory foreshadowed her eventual role in the plan. When spoken in Japanese phonetics, [=ClayDoll=] shares pronunciation with "''cradle''".
* Keeping with the theme of pairs, the two Kamen Rider Double Returns movies are essentially two sides of the same coin, or in this case, plot, in which the villain tries to break the hero. One side shows the villain failing (Accel's movie) and the other side shows the villain succeeding (Eternal's movie).
* Why is the weapon for the Metal Memory a shaft? It has something to do with metal pipes and steel beams used in construction work.
* One interpretation of the hands in prayer in Buddhism is that the left hand represents the person praying, and the right hand represents Buddha or the spirit. Now look at Double's default form: Shotaro's side (the body) is the ''left'', while Philip's side (the spirit) is on the ''right''. With this in mind, [=FangJoker=] makes sense as a ''reversal'' of Double and the "hands-in-prayer" symbolism. Philip takes over as the body (right), while Shotaro becomes the spirit (left).
* Ryu uses the same sort of purified Gaia Memory as Shotaro and Philip, and yet he seems to have a lot more to play with as a Rider--transforming into a motorcycle notwithstanding, his weapon comes with a multi-purpose Pseudo-Memory, something only seen with CycloneJokerXtreme. This is because the Accel Driver is third-generation, not only more advanced but seemingly tailored to use one specific Memory or category of Memories. It's like comparing a GP to a cardiosurgeon.
** This might also explain why the Accel Driver is the ''only'' third-generation driver we see; the time and cost of building a specialty TransformationTrinket would exceed the average budget. Not to mention that if each one is tailored to a subset of Gaia Memory, then any demand for such a device would be minimal over a multi-purpose second-generation driver or simply sticking the Memory in your arm.
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[[folder:Fridge Horror]]
* How did both Shotaro and Philip have the knowledge of doing a Twin Maximum drive, and it's consequences? They tried it before.
** Shroud warned them at some point... Though why she'd bother to warn ''Shotaro'' is anyone's guess.
** Philip may have looked up "Twin Maximum" one time and thought, "Better keep Shotaro from trying this."
* Isaka killed off other people to evolve Gaia Memories, which he then absorbed himself. He has dozens of Living Connectors all over him. If each of those is from a Gaia Memory he's absorbed...
* It's easy to imagine Ryu becoming just like the Commander Dopant if Philip and Shotaro weren't there for him. Raises questions about what in the world was Commander planning to do with his upgraded powers.
** Even more easier if he partnered up with Phillip to begin with as Shroud wanted.
* Take the Spider Dopant's curse into consideration (in which if you touch the ones you loved, they'll explode) and how Narumi had this curse, even when the Spider Memory is broken. There's a scene in Begin's Night where Narumi slaps Shotaro. Notice how he didn't blow up after that? With this in mind, the conclusion soon becomes clear: Narumi never really loved Shotaro, or at least as much as he loved Akiko.
* Ever wonder why you hear a sort of military motif in ''Stay The Ride Alive'', as well as see a bunch of soldiers in the music video? Well, consider how the movie this song was made for dug into more of the event that cost Shotaro's mentor his life. Couple this with Tsukasa's death in his portion, and it makes sense that this gives off vibes of a soldier's funeral.
* In "Forever A to Z", all the T2 Drivers seek out the people in the city they're most compatible with. Raises questions about what it says about Watcherman, considering that he's singled out by the Violence Memory.
** Given that quite a few times he's the ''victim'' of slapstick violence during the course of the series, it could be a reflection upon that rather than his own possible violent tendencies.
* To prevent the problems of Gaia Memory addiction, the Sonozakis use Memory Drivers to transform into Dopants. This comes with weakening the Dopants powers as well, so they compensate by using the strongest Memories created... Which begs the question of what would happen if the memories were inserted the normal way, thus allowing the memories to show their full untapped power...
** This can sort of be seen with Nasca R and Isaka performing experiments on Wakana to try and get her to use Claydoll without the need for the Driver.
* Masquerade Dopants, the mooks of the season, unlike the next combatants (Waste Yummies, Dustards, Ghouls) ARE human and, unlike most Memory users, end up disintegrated when defeated. Furthermore, in massive crossovers, they end up becoming some of the multiple types of mooks that, of course, get regularly beaten down. Here's hoping those Masquerade Dopants were NOT WasOnceAMan...
** It was likely that Ryubee uses the Gaia Library to create clones similar to Philip but specialized for combat and being easily controlled.
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