Kamen Rider Den-O is the 2007-2008 series of Kamen Rider and the eighth installment in the Heisei Era.
Ryotaro Nogami is the unluckiest guy in the universe. But his life changes on the day he stumbles across a mysterious train pass that allows him to board the DenLiner, a Cool Train that travels through time.
Just as he is recovering from the shock of this, he is suddenly possessed by a monster known as an Imagin: shapeless creatures from the future that take on forms based on the ideas within their host's imagination. The Imagin make contracts with their hosts to gain physical bodies, offering to grant them a single wish. Once the wish is fulfilled, they can then use their host as a gateway back through time, aiming to destroy the past to seize control of the future.
However, it turns out that Ryotaro is a Singularity Point, a person immune to any changes to the timeline and able to resist the possession of his Imagin. He is soon corralled by Hana, a mysterious passenger of the DenLiner, into using his power as a Singularity Point and his Rider Pass to transform and fight the hostile Imagin invaders as Kamen Rider Den-O.
While Den-O's base form (Plat Form) is incredibly weak, Ryotaro can relinquish control of his body to an Imagin who has possessed him and power up. His first Imagin, a Hot-Blooded Boisterous Bruiser called Momotaros, transforms Den-O into the red Sword Form. Together, they fight crime.
The plot thickens when Ryotaro discovers that Yuto Sakurai, his sister's missing fiance, is hiding in the past for reasons unknown, and somehow linked to the Imagin attacks. Just as Ryotaro goes to confront him, he is stopped by none other than a younger version of Yuto Sakurai. This version of Yuto is brash and cocky, bringing with him his own Time Train called ZeroLiner and the ability to transform into Kamen Rider Zeronos.
Despite average television ratings, Den-O proved to be a massive hit in Japan - such that on Kamen Rider's 50th anniversary in 2021, the series was voted #1 series in the Heisei era and #1 series overall by the general Japanese public in NHK’s All Kamen Rider Popularity Ranking - spawning multiple character song CDs, a spinoff anime starring the Imagin and eight movies, which is practically unheard of for a television series that was only designed to last a year:
- Kamen Rider Den-O + Shin-O: A TV special crossing the Den-O cast over with Crayon Shin-chan, as Shin-chan manages to get on the DenLiner thanks to Imagin interference.
- Kamen Rider Den-O: Ore, Tanjo! ("I'm Born!"): In a change from the then-common practice of the yearly Kamen Rider tie-in film being a Non-Serial Movie, this film caps off the show's second act and revolves around the time-traveling bandit Gaoh and his theft of the DenLiner, which he wants in order to find the forbidden "God's Line" and the powerful Time Train resting at the end. The series spends a couple of episodes teasing at the movie just before its release, then dedicated the next episode after the film's opening to dealing with the aftermath.
- Kamen Rider Den-O: Singing, Dancing, Great Training!!: A DVD special distributed by Televi-kun magazine. Ryotaro and the Taros start an exercise program to get stronger when some evil Imagin crash the party.
- Kamen Rider Den-O & Kiva: Climax Deka: Set after the series, this movie sees Team DenLiner setting up a detective agency when a rogue Imagin, Negataros, steals Owner's Liner Pass and begins forming an evil organization. Nominally a Crossover with Kamen Rider Kiva, the "crossover" is limited to a couple of brief scenes featuring Wataru and a Big Damn Heroes appearance by Kiva near the end of the final battle.
- Kamen Rider Den-O: Collection DVD: "Imagin Anime": A DVD collection of animated shorts featuring the Imagin.
- Saraba Kamen Rider Den-O: Final Countdown: The DenLiner crew must contend with the villainous Shiro and his minions, including Kamen Rider Yuuki. With Yuto injured and Ryotaro MIA (possessed by the Ghost Imagin and forced to be Yuuki), the crew must turn to Kotaro, Ryotaro's Grandkid From The Future, AKA New Den-O, who doesn't exactly think too highly of Gramps or his Imagin partners.
- Imagin Anime 2: A second DVD collection of animated shorts.
- Cho Kamen Rider Den-O & Decade Neo Generations: The Onigashima Warship: The first in the Cho Den-O film series, this movie ties directly into the Den-O arc of Kamen Rider Decade and sees the DenLiner crew, with brief support from Tsukasa Kadoya/Decade, battling a pair of Oni brothers/rogue Kamen Riders who seek to uncover a legendary and powerful battleship. Also features nominal cameos by Kiva characters (something of a nod to Climax Deka, also supposedly answering a few continuity issues with the aforementioned Decade) as well as Riders from Agito, Ryuki and the Kabuto Non-Serial Movie summoned by Decade's rival Daiki Kaito/Diend.
- Kamen Rider × Kamen Rider × Kamen Rider The Movie: Cho Den-O Trilogy: Three separate feature length films released in the span of a month, each one attempting to resolve plot points for a different set of characters, none of them are Den-O himself:
- Episode Red: Zero No Star Twinkle focuses on Yuto being forced to choose between two jobs equally important to protecting the timeline - preserving his future self's relationship with Airi, and stopping an Imagin from stealing the DenLiner.
- Episode Blue: The Dispatched Imagin is NEWtral focuses on New Den-O and his relationship with his Battle Butler Teddy, while having them battle a new Imagin and deal with a young woman and a supposedly Evil Twin.
- Episode Yellow: Treasure DE End Pirates focuses on... Diend, who thanks to Imagin possession, has stolen the DenLiner, but is pursued by Kamen Rider G Den-O, a new Rider who resembles a Metal Hero. This film gives Diend his own Complete Form to make a spectacle of the situation.
- Imagin Anime 3: The third and last DVD of animated shorts.
- OOO, Den-O, All Riders: Let's Go Kamen Riders: The final movie where Den-O characters have a starring role (though they'd continue to make appearances in franchise-wide crossovers), although, differently from Climax Deka and Onigashima Warship, the other titular stars are main characters too. This time around sees the DenLiner crew, led by New Den-O, team up with Kamen Rider OOO, Kamen Rider 1 and Kamen Rider 2 to correct a timeline divergence caused by OOO's ally Ankh. All the other main Riders and also many secondary Riders also appeared in a Big Damn Heroes role for the series' 40th year Milestone Celebration.
- Kamen Rider Den-O: Pretty Den-O is Here!: The first new project in since Let’s Go starring the Den-O cast (or at least the Taros Brothers) as the Den-Liner visits the year 1989, picking up a runaway little girl when Shocker attacks and hijacks Den-Liner!. The main character of Kamen Rider BLACK RX makes his cameo appearance.
Partnered with the Super Sentai show Juken Sentai Gekiranger after initially airing alongside the final episodes of GoGo Sentai Boukenger in the Super Hero Time block.
Followed by Kamen Rider Kiva.
From start to finish, the Character Page is always at a climax!
Recurring Kamen Rider tropes include:
- Calling Your Attacks: Used, parodied, subverted and more. Momotaros announces his finishers with "My Hissatsu Attack... Part [number]!" or "[X] Version!", even if it's not visibly different from previous variations. In one episode, he realizes he's lost count and Ryotaro advises him to just pick a random number. Meanwhile, Kintaros announces "Dynamic Chop!" after he's performed his finisher.
- The Movie: Den-O has eight feature length films (three of which premiered as an anthology), with the most recently-announced as a Milestone Celebration for 40 years of Kamen Rider.
- Multiform Balance:
- Den-O's forms are tied to which allied Imagin is possessing him at the moment:
- Plat Form (geddit?): The base form of the Aura Armor, used when Ryotaro is acting on his own without any Imagin. Almost useless in a fight (but it doesn't stop Ryotaro from trying and get his ass kicked though).
- Sword: Possessed by Momotaros. This is the balanced form.
- Rod: Possessed by Urataros. Has high defense but low offense. This form is good for aquatic combat, and the DenGasher rod mode has the power of capturing an escaping enemy.
- Ax: Possessed by Kintaros. Slow but strong, and has the best defense.
- Gun: Possessed by Ryutaros. Faster than Sword Form and armed with a powerful DenGahser gun mode. Ryutaros also incorporates break dancing into his fighting style, making it hard to predict. However, Ryutaros's trigger-happy carelessness tends to cause serious collateral damage.
- Wing: Possessed by Sieg. Even faster than Gun Form and armed with a combination of a boomerang and a handaxe. But Sieg is the Sixth Ranger of the group, often not available, and the team loathe him. His arrogant attitude also makes him prone to making mistakes in battle. Generally exclusive to movie appearances, though it made a couple teaser appearances in the series beforehand.
- Climax: Combines powers of the four Taros into one form. This form requires a Climax Cellphone K-Taros, and all four Taros need to work together controlling a single body.
- Super Climax: Even more powerful than Climax Form, at the cost of fusing with Sieg. This one only appears in spinoff movies.
- Liner: After some Character Development, Ryotaro can use the DenKamen Sword to transform into this form without being possessed by Imagin. It's the fastest form and relatively stronger than most, except Climax Form. The downside is Ryotaro's low combat skill, which is remedied to a degree as he can select one of the Taros to advice him through the DenKamen Sword, allowing him to utilize their fighting style depend of the situation.
- Altair: His default balance form. Also, Deneb is independent from Zeronos in this form and can assist him otherwise.
- Vega: Fused with Deneb. Becomes slower but stronger as well as gaining improved defense and being equipped with a powerful set of Shoulder Cannons.
- Zero: Transformed by using the Red Zeronos card. Marginally weaker than Vega Form but much faster than Altair Form and equipped with a powerful Denebick Buster gun (which can qualify as both BFG and Gatling Good).
- Den-O's forms are tied to which allied Imagin is possessing him at the moment:
- Victim of the Week: Common for Kamen Rider, to the extent that future series like Double and OOO have adopted it. Even the multitude of Den-O movies uphold this tradition, so much that some unexpected examples turn up (young Ryotaro in Ore Tanjou, young Yuto in Onigashima Battleship, and even G Den-O in Chou Den-O Episode Yellow.)
I don't have any tropes left to faint!
- Anime Theme Song: The opening of each episode features a song carrying an anime-esque tone with an introduction, a dark verse and an uplifting chorus.
- Arc Words:
- "The past should give us hope."
- "Climax Scene" for the episodes leading into the first movie, which, in the "aftermath episode", also brings us the Climax Form.
- Anime Hair: Any time an Imagin possesses a human, their hair will be restyled and gain at least a shock of a new color; rarely, an accessory may be included, such as Sieg's feathered boa or Urataros' glasses. The style, color and accessories are consistent across hosts, but oddly never appear on the Imagin themselves.
- Back to Base Form: After the Death Imagin managed to defeat both Den-O and Zeronos in their Liner and Zero form respectively. He ends up being defeated by Sword Form's finisher which is empowered by all of his allies, but not before also being attacked by Rod, Axe, Gun and Zeronos Altair form.
- Badass Family: The Nogami family, giving us two Den-Os (Ryotaro and Kotaro), Zeronos/Yuto, and Badass Normal Hana. Airi, not so much, but hey.
- Be Careful What You Wish For: A regular occurence with evil Imagin. They'll take their victim's wish and take heavy liberties with it, usually taking the interpretation that causes the most destruction.
- Big Budget Beef-Up: The last few eps.
- Bigger Is Better: The Onigashima Battleship is huge. Comparing it to the DenLiner is like comparing Daijinryu to a normal Zord. However, the DenLiner's size and speed proves to be a major asset, allowing it to evade most of the shots fired at it and enter the battleship.
- Blipvert: Kai can dig into people for their memories, which turn out looking like this.
- The Cameo: Given Den-O's long-running popularity, it's easier to list instances where there aren't cameos. However, some of the cameos stand out regardless.
- In episode 9, the master of the dojo who gets tossed out the window by Kintaros is played by Jiro Okamoto, Kintaros's suit actor. Various other martial artists who get beaten up in that same scene are also suit actors (including Eitoku, Urataros's suit actor).
- Wataru, the protagonist of Kamen Rider Kiva, makes a limited appearance in the Climax Deka film.
- Kiva's Arms Monsters return for another short cameo in The Onigashima Warship. Mimicking Kiva's lesser importance in the previous crossover movie, they don't make sure that you notice.
- Casual Danger Dialogue: Regularly. Enforced at times, when Den-O is suddenly able to off-handedly swat away the guy causing trouble.
- Close-Enough Timeline: While time can't be outright rewritten for the better, minor changes are allowed here and there provided that it's incidental to fixing the actual damage. The series ends on this too, as with the death of Kai the Taros, Sieg and Deneb should fade away. However, the strong memories they've made with the main cast allow them to exist beyond their initial timeline.
- Combining Mecha: While not as large as a Sentai mecha, the time trains fulfill the same function.
- Seven years later, Den-Liner will combine with a Sentai mecha: the ToQ-Oh Kyoryujin feat. Den-Liner!
- Continuity Nod: The drawing of Ryotaro's parents from Ore Tanjou shows up all the way in Chou Den-O Episode Yellow. Can be considered Book Ends as these are the first and last times Takuya Mizoguchi starred as Ryotaro.
- Continuity Snarl: In #39, Yuto is shown as a high-schooler in 1993. However, in the Kamen Rider Decade crossover film The Onigashima Battleship, he's shown to be 10 years old. While this could be written off as an AR version, it's established that Decade visits Den-O's home series, not an A.R. version of the show.
- Cool Train: The show is built on them, particularly the DenLiner, ZeroLiner, GaohLiner, and KingLiner.
- Creation Myth: Invoked in the first Movie, as Gaoh is after a traintrack that goes to the beginning of time.
- Critical Annoyance: In Chou Den-O Episode Yellow, Daiki/Diend hijacks the DenLiner to rectify his own mistake in the past, and manages to get around G Den-O with three minutes to spare — upon which the clock starts beeping down. It will become the longest three minutes in your life.
- Crossover: In the movie Climax Deka, the show was briefly crossed over with the 2008 series, Kamen Rider Kiva. The fourth Den-O movie takes place after its story arc in Decade and has cameos by the Arms Monsters from Kiva.
- Curb-Stomp Battle: Ore, Tanjou! has Gaoh's minions easily falling against Wing (in a separate battle), Rod, Ax, and Gun Forms. Sword Form, on the other hand, was the one in trouble, since he was facing Gaoh himself...
- Of course, the tables turn when Gaoh returns to the GaohLiner - turns out that, while extremely powerful in its own right, it's not disposed towards fighting against six other time trains linked together, each armed to the teeth. The fact that Gaoh attempted a ramming strike against the ZeroLiner, which has a drill for a weapon really just sealed the deal.
- Dancing Theme: The Taros and Deneb (and Kivat in the Crossover movie) can be seen dancing to "Climax Jump" at the end of the opening credits.
- Deadly Dodging: At the beginning of Episode Yellow, the Taros surround the possessed Kaito, he dodges, and the Imagin all hit each other in a Cross Counter.
- Demonic Possession: A more benevolent version, and the only way the Taros can interact with the physical world until they properly initiate and fulfill their contract with Ryotaro. Played for humor in Climax Deka, where Momotaros is accidentally shunted into Wataru Kurenai's body. In the fourth movie, the Taros possess the Arms Monsters as well as DiEnd-summoned copies of G3, Caucasus, and Ohja. Tsukasa/Decade himself gets possessed by all four Taros Imagin and Sieg, while Yusuke/Kuuga is possessed by Momo and Natsumi gets possessed by the other three main Imagins at different points.
- Denser and Wackier: OHHH YES. Aside from being Lighter and Softer than the previous incarnation, Den-O is FULL of funny moments stemming from Ryotaro's bad luck and the Taro's possession hijinks. They even happen a lot during battles.
- Early-Bird Cameo: Unlike the previous 6 series, Den-O averts the trend of having the hero's final form debut in the summer movie. Likely due to a combination of taking place earlier than most of the movies (which either were an alternate ending/continuity or took place around the point where the final form debuts in-series), as well as the fact that, since Ore Tanjou is completely canon to Den-O, circumstances prevent the form from being used.explanation
- Everyone Is Related: By the end of the series we learn that most of the primary human cast is related — Yuto is Airi's future husband, and Hana is their daughter, making her Ryotaro's niece. And of course, we have Kotaro in the later movies.
- Expository Pronoun:
- The two main Riders: Ryotaro uses “boku” and Yuto uses “ore”. Ryotaro is mild-mannered, even-tempered, usually non-confrontational, and generally more polite. In contrast, Yuto is hot-headed, rougher, and more willing to pick a fight. This choice of pronouns also suit their Sensitive Guy and Manly Man dynamic.
- The main Imagins:
- Momotaros, Kintaros, and Deneb use “ore”. Momotaros is without a doubt the most Hot-Blooded and least bothered with manners of the cast. Kintaros has the personality of a manly samurai and is the physically strongest of Ryotaro’s Imagins. Oddly averted for Deneb, though, as he is one of the nicest members of the cast despite using “ore”.
- Urataros and Ryutaros use “boku”. Urataros is smooth, well-spoken, and a charismatic speaker, and his choice of “boku” immediately contrasts Momotaros’s “ore”. Meanwhile, Ryutaros is the most childish of the cast, so him using “boku” emphasizes his child-like personality.
- Sieg uses “watashi”. “Watashi” is a gender-neutral pronoun, but more commonly used by women, which fits his Camp mannerisms. However, it also has a superior air to it, and in anime, is sometimes used by people who are royalty or have a god-like complex. Which, considering Sieg’s haughty and royalty-like attitude, is rather fitting.
- Fake Defector: Urataros in #48.
- Five-Man Band Concert: The "Do It Yourself" Theme Tune, "Climax Jump", uses this trope. The Imagin Four-Temperament Ensemble provides both the vocals and instrumental accompaniment separately. They sing as a quartet with only microphones in front of them (and act as backing dancers when one takes the lead). In interspersed cuts, they are playing rock band instruments. All four possess the protagonist, Ryotaro, to aid him in battle — turning Ryotaro into the absent Leader. Momotaros is The Lancer and on the electric guitar, Urataros is The Smart Guy and on the bass, Kintaros is The Big Guy and on the drums, and Ryutaros is The Baby of the Bunch and the DJ.
- Four Is Death: Played for laughs with Momotaros, who calls his attacks "My Special Attack, part [insert number here]!"...but when he does this the fourth time, he skips straight to 5. When Ryotaro calls him out on this, Momotaros just shrugs it off instead.
- Funny Background Event: Usually inside the DenLiner, especially with Naomi and Ryutaros.
- Gratuitous English: All of the belts speak entirely in English. Momotaros' use of the word "Climax" also counts as a more standard use of the trope.
- Heroic Sacrifice: The Taros, Sieg and Deneb have no problem protecting the timeline from their kin, even if it means that if the Imagin race are successfully defeated, it would mean the end of their own existence as well. Prior to the final battle, Kai himself calls them out on this, asking them if it's okay for them to disappear for the sake of the humans. The one who had the problem for this setup was instead Ryotaro, leading him to go Achilles in His Tent, and even have a brief falling out with his partners.
- Hypocritical Humor
- In Episode Red, the Piggies Imagin and Den-O (as Climax Form) throw insults at each other for Sharing a Body (the Piggies Imagin with his siblings). In the end, however, they both agree that the whole concept was gross.
- Also, earlier in that same movie, Urataros corrects Deneb for calling him "Kametaros", then proceeds to call Deneb "Odebu", only to ignore Deneb's own correction.
- In Episode Yellow, Momotaros (in Climax Form) derisively says "What's with that form?" when he sees Diend's Complete Form.
- Identical Grandson: In the third movie, Airi, Miura, Ozaki, and supposedly older Sakurai's ancestors in 1729 are played by the same actors.
- In Spite of a Nail:
- Although a lot of plot points are made of Den-O and rampaging Imagins making changes to the timeline for better or worse, a big point is also made of how it's fairly difficult to change the flow of time because it's based on people's memories (so the past will mostly only change for those who are there to witness and remember it changing,) and because sometimes that's how life goes. One example being a contract holder who regretted missing his audition and failing to make it big — Den-O helps him get to the audition but he failed, ending up in the same place he was at the start of the two-parter.
- Those important to time, like Singularity Points and Riders, will survive even gigantic changes to the timeline.
- Intercontinuity Crossover: Ultraman Taro of the Ultra Series appears in the last episode of the third Imagin Anime.
- Interface Spoiler: A non-video game example, oddly: the henshin belt has 4 buttons on it, indicating that Ryotaro will have 4 different Imagin possessing him for different forms, even Color-Coded for Your Convenience so you know that those all-yellow and all-purple Imagin are gonna be part of the crew. And then Sieg comes in to give him a fifth form, subverting it partially since it's rarely used. Deneb is also shown able to use the system when he possesses Kotaro, giving a form that's similar to Zeronos' own Vega Form.
- In the Style of: "Double-Action" again. And again. And again...
- Jackass Genie: Sure, the Imagins will grant your wish... but they'll always choose the interpretation of it that will cause the most harm to you and others. Example : "I want to play soccer again!" "Okay, I'll just put the other players into hospital!" Though this could be justified due to the fact that they're not actual wish-granting genies, and thus try to find any loophole they can to render the contract "complete" and thus allow them to travel to the past with as little effort as possible.
- Jidaigeki: In the first, third, and fourth movies.
- Laser-Guided Amnesia:
- The Zeronos cards erase people's memories of Yuto when they're used. The green ones affect memories of the elder Sakurai, while the later red ones involve those of his younger self.
- In the episodes leading up to Ore, Tanjou, Yuto keeps kidnapping Ryotaro to recruit multiples of him for the "climax scene" and wipes his memory of the event afterward. Unfortunately, the episode following the movie reveals that messing with Ryotaro's memories has consequences and nearly kills the Imagin.
- Leitmotif: All the belts make some kind of music during transformation, but the big-band themes in the soundtrack fit this trope closer.
- Let's Get Dangerous!: When you hear Liner Form's primary theme, you better expect this!
- Lighter and Softer: This trope is one of the reasons Den-O is so popular.
- MacGuffin Super-Person: Hana, who is revealed to be the Junction Point, a special type of Singularity Point whose destruction will ensure the existence of the Imagin.
- Magic Missile Storm: The Boistous Shot, Climax Form's Gun Form-based 'Charge And Up' finisher is this.
- Meaningful Name:
- "Den-O" is written with Kanji, instead of Katakana, using the characters for "(Electric) Train" and "King".
- Also, the Imagin-less "Plat Form" is both this and, as stated at the start of the article, an Incredibly Lame Pun. Y'know, seeing as it serves as the platform of all the other forms and all.
- A couple in Chou Den-O Episode Yellow:
- G Den-O is partnered with the first artificially-created Imagin - instead of naming it Adam, it's named Eve, who was responsible for the great fall from Eden.
- It's heavily implied that G Den-O's mother was barred from ever seeing him because his aristocratic family didn't approve of her background. She's named Sayuri.
- The Imagin themselves. Their name is based on the English "imagine," the Arabic "djinn" (more commonly known as genies), and the Japanese "ima jin" (literally "now person").
- Mecha Expansion Pack: In a technical sense, the KingLiner for the DenLiner.
- Mechanical Monster: All the time trains have this to some degree, what with the various animal motifs that their chassis and weapons embody. The GaohLiner comes across as one stronger than the others though, given that its transformation not only has it regularly rear back like a snake but also roar into the air.
- Mundane Utility: The DenLiner is, and always has been, a passenger train (time-traveling, yes, but you get the point). The fact that it's a heavily armed one doesn't seem to gather much comment.
- Mythology Gag:
- And Momo, Ura, Kin and Ryu have horns arranged in a manner resembling Hibiki, Ibuki, Todoroki and Sabaki respectively.
- As pointed out in the design book Imagin: Say Your Wish..., the first few enemy Imagin correspond to Riders from Kamen Rider Ryuki: Bat to Knight, Chameleon to Verde, Crust to Scissors, Crow to Odin, Rhino to Gai. Additionally, as mentioned under Actor Allusion, the Cobra Imagin is designed to resemble Ohja, and is also voiced by the same actor. Sieg also takes after Femme, and got to engage in a Curb-Stomp Battle against Cobra like how Femme killed Ohja.
- The Spider Imagin is a double subversion of this - while there was no spider-themed rider in Ryuki,note it is a reference to the traditional spider-themed kaijin that are present in most series (and was the theme for one of the first monsters fought in the original Kamen Rider).
- According to Re:Imagine - Detail of Heroes 03, the villains from Onigashima Battleship are modeled onRiders 1 and 2 (Goludora) and V3 (Shilubara). They also not only draw upon the gold and silver-themed heroes of GARO, but transform the same way.
- The Anthopper Imagins are Expies of the Double Riders of the original series. On another note, the two Imagins are even a homage of the PunchHopper and KickHopper of Kamen Rider Kabuto.
- Negative Continuity: Between the movies; Climax Deka ends with the group deciding to keep their detective agency open; Final Countdown makes no mention of it, and Onigashima Battleship might not even be in the same continuity as the rest of Den-O due to being a Decade Alternate Universe.
- New Powers as the Plot Demands: Of a sort. The show revealed and explained details about the world at a very relaxed pace, such as not explaining why everything reset itself after the Imagin doing the destruction was destroyed until around the half-way point of the series. Sometimes the rules aren't even explained verbally, leading to events that feel like they come out of nowhere, such as the Taros being able to freely possess others after they'd completed their contract with Ryotaro and being able to use the Den-O belt on their own, much like Sieg was able to. Once showcased, however, the rules remain fairly consistent.
- By the time of the crossovers though, the rules seem to have been altered a bit. For example, the core Imagin form Climax Form without a human host, and rogue Imagin who complete their contract and travel back in time now steal their host's own time, dissolving them (see Retcon).
- Oni: While Momotaros is the most obvious, the other Taros also look like oni because of their horns and their faces resembling hannya masks.
- Paper People: The style of the Imagin Anime shorts. Gets outright self-aware in one episode.
- Rearrange the Song: Den-O is known for this. "Double-Action" and "Climax Jump" have been remixed several times. For a sample of "Climax Jump": Den-Liner Form (all four Taroses), Sword Form (hard rock for Climax Jump, eurobeat for Double Action), Rod Form (ska), Ax Form (ENKA), Gun Form (hip hop), The Final, Chō Climax Jump...
- Retcon: The Chō Den-O Trilogy changes the rules on Imagin time travel from the show, now saying that if an Imagin successfully travels to the past, the act will destroy the contractor's past self (via dissolution into sand), whereas in the show proper the Imagin simply emerged from their contracted human without any effect until they started wrecking the past. Unless this is some sort of fallout from the final episode, this reflects rather badly on Kintaros, as he was one of the Imagin who completed his contract and travelled back in time.
- Reunion Show: Kamen Rider Den-O & Kiva: Climax Deka.
- Ripple-Effect-Proof Memory: A very important plot point; all Singularity Points essentially have this and, as time is based around memories, they effectively keep time from falling apart when it is changed. Though they don't remember every single thing, they restore what they remember, which then allows other people to remember how things were, creating a ripple effect that restores the timeline. The only exception is for things that people simply do not have sufficient memories of, such as the invading Imagin, erasing them from the timeline and undoing any effects they may have had on it. This becomes a massive problem for Yuto as, due to the Zeronos cards erasing peoples' memories of him, nobody remembers his actual life when Kai manages to kill him, resulting in a vastly different timeline where he never lived. However, this rebounds when Yuto reveals that a side-effect of the Zeronos cards grants him Ontological Inertia.
- Rule of Cool:
- Again, Riders on horseback.
- Not until Kamen Rider OOO will you see all forms of a single Rider transforming and fighting side by side.
- Set Right What Once Went Wrong: A rather confusing one, actually, as there are only certain things that can be fixed and it seems the only way you're allowed to do it is if you're stopping an Imagin in the process. Several times, someone in the group alters the past so that the person never made the Deal with the Devil with the Imagin in the first place, negating the wish altogether along with all the damage the Imagin caused, including what normally would've been erased for good. While things will continue as they originally did in these cases, the Victim of the Week normally comes off much happier for it. For example, a man who originally missed his band's recital and blamed himself, becoming obcessed with getting enough money to make it big had time altered so he did make the recital but his band still didn't make the cut. However, the man was now trying to make his way to the top through his own talent and hardwork instead of buying his way there and was much happier than in the original timeline.
- Shared Universe: Climax Deka seems to indicate that Den-O and Kiva are set in the same 'verse, just like Kuuga and Agito. This was compounded in Onigashima Battleship with the random cameo appearances of Kiva's Arms Monsters.
- Not sure if it's a shout out or would be classified as something else, but there's a very obvious parallel between Den-O and Juken Sentai Gekiranger. In Gekiranger, the team is made up of 5 people in Red, Blue, Yellow, Purple, and White. In Den-O the team is made up of 1 person with other people in him corresponding to the colors Red, Blue, Yellow, Purple, and White (for Wing Form). Also, in both shows, The Rival has the colors Green and Black related to them in some way. Interestingly, both shows aired alongside each other. An announcement of a Geki/Den-O joint promotion even ends with the five Gekiranger mimicking the poses of their respectively colored Imagin. As if returning the favor, the Imagin would later appear in promos for the Kiva Movie, but mimicking the Catch Phrases of the next Sentai, Engine Sentai Go-onger.
- Teddy displays the Newtype Flash when protecting Kotaro from bad luck.
- Shown Their Work: A minor bit of trivia about Sanada Yukimura states that dango is his Trademark Favorite Food — in Ore Tanjou Ga-Oh takes over Sanada's castle, commanding all his slaves to dig for the GaohLiner, and is shown taking a big plate of Sanada's dango as a Kick the Dog gesture.
- Sliding Scale of Idealism Versus Cynicism: Den-O skews very idealistic; out of all the Imagin contractors, all but one or two are good people whose wishes were well-intentioned (or only slightly misguided, but they see the light at the end of the arc). Yuto initially thinks Ryotaro is soft for putting so much effort into helping the victims rather than just fighting the Imagin, but eventually comes around to the DenLiner crew's way of thinking. Even when Sakurai disappears into the timestream at the climax, it's treated as a temporary separation rather than Killed Off for Real.
- Spinoff: Imagin Anime
- Surprisingly Realistic Outcome: Because of how Den-O always tosses his Rider Pass away after activating his Finishing Move due to Rule of Cool (regardless of who is in control), oftentimes the cast end up having to scour the area for where the Pass had landed after the battle is over to retrieve it, much to Hana's chagrin.
- Swiss-Army Weapon: The DenGasher and ZeroGasher both have the ability to change into different weapons with a little bit of parts-shuffling. Naturally, their toy counterparts can do the same.
- Tap on the Head: At the beginning of Ore, Tanjou!, Gaoh kicks Ryotaro in the head. This gives him amnesia (though only regarding matters concerning Den-O and the Imagin) through most of the film which, since the Imagin are based on memories, disrupts Ryotaro's effectiveness until he gets it back just in time for the big fight.
- Theme Music Power-Up: Most big fights with Imagin will have the relevant version of "Double-Action" playing. "Climax Jump" starts up during the debut fight of Climax Form.
- Throw the Dog a Bone: Ryutaros meeting Airi for real in Climax Deka and even receiving a bento lunch from her.
- Time Crash: Shiro's big plan in Final Countdown involves bodyjacking Ryotaro and making him destroy his own ancestors in the past, which should have this effect. It's disproved later on in Episode Yellow though.
- Time Police: What the DenLiner crew see themselves as. Later, in Episode Yellow, G Den-O, an officer from an actual time police force appears.
- Time Travel: As part of the premise; the DenLiner can travel through time and will take people to a specific time that they have passes for. Imagin, on the other hand, can travel into the past directly by traveling through someone's memory (as "time" is, in this series, made up entirely of people's memories of past events).
- Too Long; Didn't Dub: A source of controversy in the fandom is subbing group TV-Nihon leaving as many honorifics as they can in the subs. While it wouldn't be too surprising for Japanese-themed series like Shinkenger, expressions like "cow-san-tachi" (seen in the Imagin Anime) can be jarring for fans with a minimal knowledge of Japanese. This is actually a recurring problem with said group.
- Tricked Out Time: When Ryotaro or the Taros change time, Owner allows it so long as things don't change too much. Thus, most of Ryotaro's travels to the past end up with him helping the Victim of the Week with their issues by changing the past just that tiny bit.
- Uniqueness Decay: I'm Born!! treated the battle with all four Den-Os as a unique and special event, only possible because Yuto "borrowed" Ryotaro from three other points in the timeline. After the final story arc, where the Taros "complete" their contracts with Ryotaro and thus gain physical form, the Taros gain the ability to transform into Den-O on their own (as well as spontaneously possessing their own copies of the belt and Rider Pass). As a result, just about every post-series appearance from Final Countdown onwards features all the Den-Os fighting as a team, making I'm Born!! a lot less "unique and special" than it originally was.
- V-Formation Team Shot: SIX Den-Os plus Zeronos in Final Countdown.
- Villain-Possessed Bystander: The monsters are Jerkass Genies who distort peoples' wishes (which are, with perhaps two exceptions, well-intentioned or merely misguided. The Hero, a very compassionate young man, makes helping the Victims as much a priority as fighting the monsters.
- Villain Protagonist: All of the Taros (minus Kin) start out as this.
- Villain Team-Up: Climax Deka, where Negataros recruits several Fangire into his evil organization.
- Wham Episode: #39: after some usual hijinks for most of the episode, we then get treated to a past version of Yuto actually being killed by the Snail Imagin, causing the present Yuto to disappear.
- Wham Line: What sets off the Darker and Edgier tone of the final leg of the series:Kintaros: Your wish has been granted.
- Who Would Want to Watch Us?: One episode of Imagin Anime shows the Taros' as producers at Toei, and they end up haphazardly creating their own series.
- Widget Series: The crowning example within the Kamen Rider franchise.