History Fridge / KamenRiderDecade

* The finale has Super Apollo Geist bring back 6 of Tsukasa's adversaries from the Nine Worlds. Notably, the Gurongi, Mirror Monsters, and Makamou have no representation whatsoever. One possibiity is that, with the Gurongi, it already happened back in #3, where Gamio absorbed his sired Gurongi to give himself more power against Decade and Kuuga, while most (if not all) Mirror Monsters and Makamou behave like feral animals in general.

** Kabuki and Rey were [[spoiler: both good guys with dark, if [[AntiVillain somewhat good]] intentions that eventually made them side with the villains]]. [[spoiler: They might be to foreshadow Kaito's stance in the show]].

** Scissors and Raia are based off sea life, ironic since they are fighting a sushi maker. Also, The two riders are from a show that the same writer from Shinkenger wrote.
** G3, Caucasus, and Ohja share the same colors as the Taros sans Momotaros.
*** Coincidentally, there's also a bit of brilliance in the order the Taros' react to Momo possessing Decade - not only is it the airing order as the series the 3 riders were summoned from came from (Agito, Ryuki, Kabuto - Urataros, Ryutaros, Kintaros), but the order they reacted was also the same as the order all 3 types of riders other than the main rider (heroic secondary rider, villainous secondary rider, movie exclusive rider) would appear in.
** Punch Hopper, Raia and Gai [[spoiler: were killed by Kick Hopper and Ohja respectively.]]
*** It turns into Fridge Sorrow when you notice that [[spoiler:Kick Hopper didn't murder Punch Hopper in cold blood like Ohja. He did it as a MercyKill]].

** And WhatCouldHaveBeen indicates that there were plans for a legitimate EvilCounterpart, one that even received some {{Foreshadowing}}. Remember how in the first episode he was in Kabuto's World, he encountered a Worm that took his form? This was likely meant to foreshadow that in ''The Last Story'', [[spoiler: he would be fighting against [[EvilCounterpart Dark Decade]]. Of course, because this was ScrewedByTheNetwork, it wound up being [[DemotedToExtra Demoted To]] BigLippedAlligatorMoment, instead, but it's the thought that counts.]]

*** And by extension: Why didn't Diend find anything worth taking in the World of Blade? Because he's ''from'' the world based on ''Blade'''s summer movie - odds are that what would have interested him is in the world he's from! Odds are that if ''Paradise Lost'' had an AR world similar to ''Missing Link'' being the basis for the "World of Diend", he wouldn't have found anything worth taking in the World of Faiz, either!

* Tsukasa's catchphrase makes sense when you realize what he was supposed to do. "I'm just a passing-through Kamen Rider. ''Remember that''." [[spoiler: His mission was to make people remember Kamen Rider and thus save their worlds from fading into obscurity/being destroyed]].
** There's another reason too. [[spoiler: When he died, he was saved because people ''remembered'' him]]. It was a sort of Gambit to make sure [[spoiler: he lives through his mission]].

** Adding to this, the Finale movie confirms that this can be done completely against the Rider's will, when Decade [[spoiler: turns Blade into the Blade Blade and uses him to kill the Rider Blade had been fighting alongside moments before.]] Imagine being [[AndIMustScream turned into a weapon and being used to kill one of your own allies while you're totally powerless to stop it]].

* Natsumi became a rider at one point and died at later point. Normally this applies for Female Rider Curse, but the scary part? She became a rider against her own will by the Taros. In other words, the lovable bunch of characters just gave someone their ''death warrant''.

* Onodera's being weaker than Godai, while frustrating, makes a lot of sense. First off, due to Tsukasa's help (or interference if you prefer) Yuusuke was force to deal with the BigBad of his world much earlier than his original counterpart did. Well before he had the opportunity to take the numerous levels in badass that Godai needed to solo the entire Grongi race. Secondly, with the Gurongi defeated, and Tsukasa being pretty much alright on his own, Yusuke probably had less motivation to fight unless it was under certain circumstances (being driven to do so, or being asked). As result he never was able to achieve the same level of strength the original Kuuga did. He could have however, had things continued in the manner they were before Decade showed up.

* Onodera's being weaker than Godai, while frustrating, makes a lot of sense. First off, due to Tsukasa's help (or interference if you prefer) Yuusuke was force to deal with the BigBad of his world much earlier than his original counterpart did. Well before he had the opportunity to take the numerous levels in badass that Godai needed to solo the entire Grongi race. Secondly, with the Grongi defeated, and Tsukasa being pretty much alright on his own, Yuusuke probably had less motivation to fight unless it was under certain circumstances (being driven to do so, or being asked). As result he never was able to achieve the same level of strength the original Kuuga did. He could have however, had things continued in the manner they were before Decade showed up.