Taros

The Rider Pass that Ryotaro Nogami uses to become Kamen Rider Den-O can summon at least four Imagin. Each of these Imagin gives Den-O their power when they are called upon with each form suiting to their fighting style. These Imagin are collectively known as the Tarōs (タロウズ) due to their namesakes. When not possessing Ryotaro, the Tarōs spend their time in the DenLiner's dining car. However, they are also able to enter physical time and space by possessing vacant forms, such as full-body costumes, although this leaves them physically unstable. The Imagin have also proven capable of possessing Ryotaro all at once after the creation of Climax Form, but outside of their transformed state, this 4-way possession is dangerously unstable and physically stressful for Ryotaro. Due to their nature as Imagin, they can sense evil Imagin near Ryotaro's vicinity and alert him likewise. In addition to powering up Den-O, the four are each armed with a weapon and each are able to perform their form of Den-O's finishing attack in their normal state.

When the Junction Point starts to form, the Tarōs start to lose sync with Ryotaro and are unable to possess him when he travels to the past. To continue to assist him, they create the DenKamen Sword, which allows him to channel their power without direct possession. Though Ryotaro is curious of these recent events, the four are reluctant to explain that it meant the future they came from is being erased, causing their kind to cease to exist as the result of their battle with the evil Imagin. In spite of it, however, the Tarōs intend to keep fighting to the end, gaining physical form within normal space-time as a result of each Imagin granting Ryotaro's wish that they fight together until the end. When the time does come and they fade away, it is revealed that the memories they made with Ryotaro have created a time lag, allowing them to maintain their existence as they take leave on the DenLiner.

Soon after, the four become members of the DenLiner Police (デンライナーポリス), a newly-made law-enforcement group to prevent changes in the past by Imagin who also survived the Junction Point and form an army under Negataros. Because of their status as Imagin who fulfilled their contracts, the Tarōs are able to possess anyone as seen with Yuto, Wataru Kurenai, Tsukasa Kadoya, Yusuke Onodera, Natsumi Hikari, the Arms Monsters of Kamen Rider Kiva, G3, Ouja, Caucasus, Kotaro Nogami, Ankh and Daiki Kaito

Momotaros
Momotaros (モモタロス) is the first Imagin that gives Ryotaro his power, which allows for the Sword Form transformation. He can also sense when an Imagin is rampaging in the city, subsequently alerting Ryotaro immediately. His natural weapon as an Imagin is a sword named the Momotarosword (モモタロスォード). Momotaros blames Ryotaro for his Oni-like form, though it matches his personality, best described as hot blooded, arrogant, and comedic, serving as a foil to Ryotaro's own shy and cowardly personality. In fact, Momotaros is more interested in fighting than carrying out the Imagin's goal. Unfortunately, he is constantly beaten by Hana when he gets Ryotaro into trouble. When he possesses Ryotaro, declaring the words "Here I come!" (俺、参上！), Momotaros's own personality takes over, giving Ryotaro power, confidence, and a bit of his eagerness for a good fight. His eagerness is shown in battle, where he always declares the words, "I am, from start (to finish), at the climax!" (俺は最初から（最後まで）クライマックスだぜ！). Momotaros is also somewhat selfish, initially fighting alongside Ryotaro in order to ensure his own survival. Though he unknowingly places Ryotaro in unneeded danger to suit his fancy, Momotaros eventually learns to respect him and his desire to protect others. Though he demands respect, Momotaros is usually put in his place by Hana and her powerful punches. He also does not know how to swim, has a narcotic reaction to red peppers, and seems to be afraid of dogs. While he acts hostile and demeaning to the other Tarōs, he does care about them, proven by hiding his anguish while they are slowly disappearing due to the events of the Climax Scene. Momotaros is the base for Den-O's Climax Form, as he has control of the head and torso and can control the other sections that the other Tarōs usually have primary control of if need be. During the events of OOO, Den-O, All Riders: Let's Go Kamen Riders, Momotaros assumed both the forms of the Momotaken for New Den-O to use and then the Imagin Medal for Kamen Rider OOO to use to assume Tamashii Combo.

When insulting another Imagin, he usually calls them a "X-Jerk" (Ｘ野郎) depending on the animal they are modeled after, or a shortened version. The other exceptions are Ryutaros, referred as "Brat" (小僧、ガキ) or "Snot-nosed Brat" (ハナタレ小僧), Deneb as "Tubby" (オデブ), and Teddy as "Tendon" (天丼). Momotaros also refers to Hana as literally "Nosy Woman" (ハナクソ女). He also puts emphasis on his final blow attacks, saying "My Finishing Attack, Part X" (俺の必殺技パートＸ) while possessing Ryotaro in Den-O Sword Form, with a Part 1, 2, 2’ (Two-Dash), 3, and 5 (Ryotaro tells Momotaros that he skipped 4, but he considers not using 4 "cool", even counting from 1-10 while skipping 4). In his battle against Kamen Rider Gaoh, Den-O Sword Form swiped the Rider Pass over the Den-O Belt twice, initiating a doubled Full Charge for "My Finishing Attack, Special Edition" (俺の必殺技・特別編). In his battle against the Alligator Imagin in Kamen Rider Decade, while empowered by Decade's Final AttackRide Card, Momotaros uses Kuuga Gouram and a DenGasher for his "My Finishing Attack, Decade Version" (俺の必殺技・ディケイドバージョン). When performing his version of the attack in his physical form, he calls it "My Finishing Attack, Momotaros Version". His physical form is based on an oni and a peach and his DenLiner train features a dog, monkey, and bird, all of which are companions of Momotarō (桃太郎) the Peach Boy. Ironically, the legend has Momotaros's namesake defeating evil oni, while Momotaros is based on an oni.

Momotaros is voiced by Toshihiko Seki (関 俊彦).

Urataros
Urataros (ウラタロス) is the second Imagin that gives Ryotaro his power, allowing transformation into Den-O Rod Form. The form given to him by Ryotaro is turtle-like in appearance, with his weapon being the Uratarod (ウラタロッド), a rod with hexagonal blades at each end. Furthermore, Urataros was well-aware of Ryotaro being a Singularity Point, making his contract to him on purpose—though he says it is to evade the loneliness of being outside time, Hana later debunks this entirely. When he possesses Ryotaro, he usually states the words, "Hey, will you let me reel you in?" (お前、僕に釣られてみる？).

He is also aware of the evil Imagin planning to destroy time, but simply does not want to commit it as in spite of his cool exterior, there's indication that he's somewhat of a coward and lies just for self preservation. Urataros is a casanova with a very convincing personality, owning the ability to convince almost anyone by speaking to them, with Ryotaro the only one who trusts him and lets him stay as he sees he has a good heart. Urataros, however, later says that he lies simply for the sake of lying ("One lie is more interesting than a thousand truths"), and seems quite irritated that Ryotaro is "trivializing his lies."

While Momotaros gets Ryotaro in trouble through reckless methods, Urataros puts Ryotaro in conflicting situations when he goes around wooing multiple women. Despite these negative traits, along with his occasional fights with Momotaros, Urataros does show genuine concern for Ryotaro's well being. Being the best speaker of the Taros, possessing Ryotaro simply to get information out of someone, or to talk his way out of something. He is also useful in situations that require patience, something Momotaros severely lacks.

He usually refers to Momotaros as "Sempai" (先輩) and Kintaros as either "Bear" (クマ) or "Kin-chan" (キンちゃん) respectively. Urataros' physical form is based on that of a turtle and fishing rods are a common motif, both of which are aspects of the myth of Urashima Tarō (浦島太郎), a fisherman who caught a turtle that led him to the castle of Ryūjin.

Urataros is voiced by Kōji Yusa (遊佐 浩二).

Kintaros
Kintaros (キンタロス) is the third Imagin that gives Ryotaro his power, which allows for the Ax Form transformation. He is vaguely modeled after a bear and has a Sumo wrestler-like personality. He also has a habit of deep sleeping (akin to hibernation) until the mere mentioning of any word that sounds remotely similar to the Japanese word for "to cry" (泣く) often provokes Kintaros out of his slumber to possess Ryotaro in an instant.

He speaks in a the dialect of Kansai-ben, saying, "My strength has made you cry. Wipe your tears with these!" (俺の強さに、お前が泣いた. 涙はこれで拭いとけ), whenever he possesses Ryotaro, taking out a handkerchief for whoever wants to wipe their tears off with. His natural weapon as an Imagin is a giant battleaxe named the Kintaros Axe (キンタロスアックス). He has a habit of popping his neck every time he begins and ends a battle, as well having "You cried" (泣けるで) as a battlecry.

Kintaros is a strong Imagin who constantly seeks opponents stronger than himself. Unfortunately, he is sometimes unable to control his own strength resulting in accidentally destroying things, which he attempts to fix afterward. He is also very selfless and had no intent to follow Kai's orders to alter time to begin with. At first, he is dependent on a retired karateka named Masaru Honjō, who gave him his "bearish" look, as he attempted to master karate so Masaru could achieve the "ultimate karate". Kintaros wants to teach Masaru the ultimate karate, in order to let him settle things with Kikuchi instead of disturbing the timestream.

Seeing the good side of Kintaros when he protects Masaru from the Rhino Imagin and being mortally wounded in doing so, Ryotaro allows Kintaros to enter a contract with him, saving the Imagin's life. Unlike the others, who had (at least partly) selfish intentions for assisting Ryotaro, Kintaros's motives for helping him are noble from the start, having a desire to repay Ryotaro for saving his life, stating so on several occasions.

He usually refers to Momotaros as "Peach" (桃の字), mispronouncing his name as "Momonga" (モモンガ) and "Momohiki" (モモヒキ)}} and refers to Urataros as "Turtle" (亀の字). Kintaros' physical form, based on that of a strong golden bear, are aspects of the traditional myth of Kintarō (金太郎) the Golden Boy, said to be strong enough to wrestle bears and demons.

Kintaros is voiced by Masaki Terasoma (てらそま まさき). Terasoma was also known as the voice of Shadow Moon from the Kamen Rider Black series.

Ryutaros
Ryutaros (リュウタロス) is the fourth Imagin that gives Ryotaro his power, which allows for the transformation into Den-O Gun Form. His natural weapon as an Imagin is a shotgun named the Ryuvolver (リュウボルバー). Though he is the last Imagin to appear, Ryutaros initially possessed Ryotaro the moment that Urataros did, and simply hid himself from the others. Ryutaros reveals himself in his form when he is attracted by Naomi's coffee inside the DenLiner. Ryutaros is most childish in personality with a love for drawing and animals. Ryutaros also appears to enjoy break dancing, to the point to that it is incorporated into his flashy fighting style. His personality is one of a fun-loving dancer/disc jockey but is reckless. This recklessness also causes the most collateral damage, as he fires his gun aimlessly.

When he possesses Ryotaro, he first asks "Mind if I…?" (…いい？) followed by "I can't hear your answer" (答えは聞いてない). He has the ability to control people simply by snapping his fingers. This tactic works with summoning the Machine DenBird as well. Originally, Ryutaros possesses Ryotaro after being promised the title of become the DenLiner's conductor by Kai, who also gives the Imagin a ticket, on the condition that he destroys Ryotaro.

However, because he does not wish for Airi to cry, Ryutaros decides not to destroy Ryotaro. The only individual he will listen to is Airi, whom he affectionately calls "sis" (お姉ちゃん). Because he knows that Airi has loved Yuto Sakurai, and from faulty advice on love from Kintaros, he becomes jealous of Yuto and wishes to show that he is stronger than him. But when Kai takes matters in his own hands in killing him, combined with realizing how he and Airi can not to be together, Ryutaros matures a bit to cope with fading away while eventually mustering courage to fight in the final battle against Kai.

He usually refers to Urataros, Kintaros, Sieg, Teddy respectively as "Turtle-chan" (カメちゃん), "Bear-chan" (クマちゃん), "Bird-san" (トリさん), and "Blue Bear-chan" (青クマちゃん). However, he excludes Momotaros as he is not based on an animal and Momotaros does not understand him like the others do. He is referred to by the others as "Ryuta" (リュウタ). After this initial arrival on the DenLiner, he is rarely seen without a pair of headphones over his head.

One of the Tarōs, Ryutaros's basis is unclear as early promotional material stated his form to be based on the legend of Tatsu no Kotarō (Taro the Dragon Boy) while TV Asahi's website for Den-O states that his form is based on Ryotaro's mental image of dragons. Two of the Imagin Anime shorts bring up the topic of Ryutaros's possible namesake.

Ryutaros is voiced by Kenichi Suzumura (鈴村 健一).