Tsukasa Kadoya

"I'm just a passing-through Kamen Rider. Remember that!"

- Tsukasa's answer when asked who he is

Kamen Rider Decade (仮面ライダーディケイド) is the main protagonist and eponymous character of the Kamen Rider Series Kamen Rider Decade. Decade's name is taken from the English word decade as Decade is the 10th of the Heisei run of the Kamen Rider Series, evidenced by the Roman numeral X (ten) on his chest. His logo features the numbers 453 and 145 below the bar code. These digits correlate to the English letters A, C, D, and E to form the word "DECADE". He is also the first Rider to have a series that crosses over with a Super Sentai TV show, in this case Samurai Sentai Shinkenger, though the honor of being the first Rider to appear in a crossover belongs to his rival Kamen Rider Diend.

Personality
Tsukasa Kadoya (門矢 士) is a hypocritical and self-righteous young man who does not know much about his past. He has a strong desire to "catch the world" using his photos, but they never develop well. He sees this as a sign that he is not of this world, unaware of it being a prelude of it being supplanted by the worlds of the other nine Kamen Riders. However as Decade, he is seen as an agent of destruction, usually being called "the devil", a rumor spread by Narutaki, who believes Tsukasa does not belong in any world.

It is also revealed that those who appear in his badly developed photographs die or foreshadow events. As Tsukasa travels between dimensions, his clothing changes to suit the Rider's World, including some accouterments similar in color to his camera and Decade. He also exhibits some prior knowledge or a talent necessary to his quest in the Rider's Worlds he enters. Some examples are his knowledge of the Gurongi language in Kuuga's World and his enrollment as a student in Faiz's World. He has also mentioned before that he is capable of doing anything except for taking photos.

Before a climatic battle begins, Tsukasa answers a major villain's demand for his identity by saying that he is "Just a passing by Kamen Rider, remember that!" (通り過がりの仮面ライダーだ、覚えておけ！).

Tsukasa uses a "Decade Pink" Blackbird, fly 135 Twin Lens Reflex Camera.

Becoming Decade
When Tsukasa is confronted by Natsumi Hikari over the photos he has taken, the two get separated by a dimensional barrier that sends Natsumi into an unstable pocket dimension where she flees for her life from various kaijin before finding the Decadriver from her dreams. While looking for her, Tsukasa encounters Wataru Kurenai, who calls him "Decade". Wataru tells him today is the day his world will end, and that he is needed to protect it.

After finding Natsumi, Tsukasa uses the Kamen Ride Cards to assume the forms of Kabuto, Faiz and Hibiki to deal with groups of Worm, Orphnoch and Makamou. Confused by both his actions and the cards's powers fading, Tsukasa takes Natsumi and returns to their world as it is being destroyed by the various monsters. When time suddenly freezes, Wataru appears, revealing the status of the worlds and assigning Tsukasa the task of traveling into the other worlds to stop the dimensional chaos inflicted on his own world by meeting the Riders of each of the other dimensions.

World of Kuuga
Starting in the World of Kuuga as a police officer, Tsukasa meets the world's Rider, Yusuke Onodera who battles the Gurongi and learns that that someone is disseminating rumors across the Worlds about him as a destroyer of worlds. After reconciling with Yusuke, the two stop the Gurongi N-Gamio-Zeda from taking over the world.

World of Kiva
At the World of Kiva as a violinist, Tsukasa encounters the young boy Wataru, helping the boy realize his role as King of the Fangire Race to maintain the peaceful coexistence of the human and Fangire races while defeating the Beetle Fangire: Wataru's father and the former King.

World of Ryuki
Then at the World of Ryuki, Tsukasa defends the framed Natsumi in a murder case and solves it with the aid of Shinji Tatsumi. The true villain, Kamata is revealed to have been an Undead all along and is taken by Narutaki to the World of Blade after his defeat.

World of Blade
Assuming the role of chief waiter under the BOARD Corporation while being promoted repeatedly, Tsukasa works with Kazuma Kendate to uncover the conspiracy between Kamata and BOARD's CEO, Kamen Rider Chalice, to take over the world through the Joker card which the latter used on himself. After he and Blade work together to defeat the Undead, Tsukasa takes his leave as Kazuma thanks him.

World of Faiz
In the World of Faiz as a student of the Smart Brain High School, Tsukasa crosses paths with a man he saw at the World of Blade who knows him, Daiki Kaito. Though Kaito warns him to stay out of his affairs, Tsukasa finds Faiz after confronting the Lucky Clover group, learning that he is Takumi Ogami as he attempts to keep his SB-555B Faiz Driver away from Kaito. Tsukasa later resolves the tension between Takumi and Yuri Tomoda over Takumi's identity, giving Takumi the will to continue protecting the school.

World of Agito
Arriving in the World of Agito as a postman, Tsukasa reads a discard letter meant for Shouichi Ashikawa, making it his goal to protect Ashikawa from the Unknown for the sake of Toko Yashiro, the writer of the letter. With Yusuke's help, Tsukasa succeeds in having Shouichi achieve the necessary state of mind needed to complete his evolution to Agito before reuniting him with Yashiro.

World of Den-O
Upon arriving in the World of Den-O, Tsukasa becomes Den-O under the possession of an Imagin, before forcing him into Yusuke's body. Here, he learns that some unknown force is changing the past as he is fought by the other Taros possessing Natsumi's body who believe Decade to be the source. Learning the Imagin possessing Yusuke is named Momotaros, Tsukasa finds him and helps him regain his physical form as they defeat the Alligator Imagin. Believing their adventures with Den-O to be over, only to learn the identity of the true culprits for Den-O World's time distortions, they prepare to travel to the World of Kabuto until the Swan Imagin Sieg comes into the Hikari Studio with a manuscript showing a battle at Onigashima. With Sieg's help, Tsukasa and company travel with the DenLiner crew back in time to fight the Oni Rider Brothers, Mimihiko and Kuchihiko, before returning to the present time in the World of Kabuto.

World of Kabuto
In the role of a ZECTrooper, after witnessing TheBee and Gattack's fight against a Worm, Tsukasa brings Arata to the Photo Studio where he finds a Salis Worm that had mimicked him. After the impostor is exposed, the Worm is killed by Kabuto when it attempted to kill a girl named Mayu whose brother was believed to have been killed by Kabuto. Although it seemed that TheBee's user, Sou Otogiri, is her brother, Tsukasa felt something was not right. After learning that Mayu herself is a Worm, both his meeting with Grandma and learning the full nature of the Kabuto Capture Plan allow him to get the full story. Arriving to Mayu's aid, Tsukasa helps Kabuto, Mayu's real brother Souji, in defeating Otogiri in his true identity, the Phylloxera Worm. After bringing Mayu back to her Grandma and giving Daiki a vial of pepper as a "treasure", Tsukasa begins the journey into the final world, the World of Hibiki.

World of Hibiki
In the World of Hibiki, Tsukasa meets a encounters an Oni in training named Asumu. From there, believed Great Master of Ongekidō (音撃道) style, Tsukasa meets the three masters of the Ongekidō Styles before being pulled into a ploy by Daiki to rob the two Oni masters Ibuki and Zanki, worsening when they are attacked by the Makamou Gyuki until Akira and Todoroki drive the beast off. Supporting their intent to end the rivalry among their schools, Tsukasa convinces Ibuki and Zanki to pass the torch. Tsukasa later offers his aid to Asumu after he became the new Hibiki thanks to Daiki, whom he still acknowledged as a thief and nothing more.

World of Negatives
With the journey over, Tsukasa and the others of the Hikari Studio return to what appears to be Natsumi's world to find it back to normal as if it was not plagued by the monsters. Despite being in a perfect world that he has earned, according to Otoya Kurenai, it is revealed that it is only a parallel version of their own world where the monsters have taken over and killed all but a few humans.

After being tested by Otoya, Tsukasa gains the K-Touch after turning down Otoya's offer to live in a world of lies, using Decade's Complete Form to take out the Dark Riders. Knowing that their journey is not really over, the Hikari Studio group heads to the next world, Kaito's homeworld.

World of Diend
Arriving in the World of Diend, he finds himself in the role of a salary man selling products to the society until he encounters Shin and Haruka, Kamen Riders Lance and Larc, fighting a Darkroach.

He learns that Daiki is the lackey of the evil Fourteen who brainwashed the inhabitants of the World of Diend to believe that Kamen Riders are evil, having unknowingly given up his brother to Fourteen. He and Daiki team up to defeat Fourteen to free all those who have been brainwashed, leaving only Daiki's brother Junichi, Kamen Rider Glaive, who was not brainwashed but accepting of Fourteen's peaceful world. He teaches the two brothers that they have to protect each other, no matter what, before heading off to the next world, one which he has no knowledge of at all.

World of Shinkenger
In the guise of a kuroko with a strange card in hand, Tsukasa learns that his lack of knowledge is due to the world not having any Kamen Riders as he witnesses the Shinkengers drive off the Nanashi. Curious about them, Tsukasa uses his guise to learn more about them and their world before fighting the Ayakashi Chinomanako who has stolen the Diendriver from Daiki. He realizes that the monster is the reason why he is in this world as Chinomanako escapes and becomes the world's first Kamen Rider. He attempts to fight the Chinomanako but is stopped by Narutaki saying that his actions will only bring doom to the world. After being given the advice to do the right thing by Hikoma Kusakabe, Decade later helps the Shinkengers with the card revealing to be the Rekka Daizantou which he uses to destroy Chinomanako alongside Shinken Red using the Blade Blade. As Tsukasa and Yusuke are welcomed home by Eijiro and Natsumi, assuring Tsukasa that the photo studio is his home no matter what, they enter a new A.R. World.

World of Decade
The Hikari Family Studio ends up in a world which is discovered to be Tsukasa's home world, the World of Decade, where Tsukasa meets his sister Sayo Kadoya and starts a tournament to find the strongest Rider to save the world after hearing he must be the one to do so by Nobuhiko Tsukikage, Sayo's butler.

Tsukasa wins and it is revealed that he was the Great Leader of Dai-Shocker. But the victory is short lived as Nobuhiko is revealed to be Shadow Moon and Sayo as Priestess Bishium takes control of Yusuke through the Stone of Earth to attack Tsukasa as part of revenge for abandoning her, despite not knowing the truth. Tsukasa is left alone as even his friends abandoned him. He is later encountered by Joji Yuki a former scientist for Dai-Shocker that wanted payback by Tsukasa for doing said punishment to him. Later he realizes that Tsukasa is no longer affiliated with Dai-Shocker and fights Dai-Shocker as Riderman as Tsukasa moves away.

Tsukasa joins in the fight against Dai-Shocker starting with the fight against General Jark. He and all of the Kamen Riders from the Showa and Heisei Era Fight Dai-Shocker destroying Ambassador Hell and Doctor Shinigami as Garagaranda and Ikadevil respectively. Later Decade fights the Bishium-controlled Kuuga Rising Ultimate but realizing he's talking with his sister, he convinces Sayo that Nobuhiko is only using her to further his goals. Sayo, knowing the error of her ways destroys the Stone of Earth, freeing Yusuke. With the stone destroyed Shadow Moon fights Decade and Kuuga Rising Ultimate overpowering them until Double shows up and flings him to Dai-Shocker's castle. Tsukasa along with all of the other riders destroy Shadow Moon with the All Rider Kick. After Shadow Moon and the castle is destroyed, King Dark appears. Diend summons J and uses the Decade Final Form Ride to turn Decade into the Jumbo Decadriver and turns J into Decade Complete Jumbo Formation destroying King Dark. Tsukasa later makes amends with Sayo and leaves with the Hikari Studio.

World of Black RX
Entering the World of BLACK RX, receiving another card being mistaken as Joe the Haze when he changes clothes and is attacked by Schwarian and his Chap minions while meeting Kotaro Minami himself. Decade then finds out that Dai-Shocker is in this world planning to conquer it. Decade teams with RX to help fend off the assault on this world. Eventually the Security Chief of Dai-Shocker, Apollo Geist drains Natsumi's life through his Perfector ending up in a hospital and Tsukasa desperate to revive her. Decade learns of Apollo Geist and the Perfector from Kaitoh and goes off to find him, but Kaitoh also has his agenda of retrieving the device. Decade, with assistance from RX, battles Geist but Guy leaves through a dimension wall. Tsukasa follows him in pursuit but ends up in Kamen Rider BLACK's World with no way out.

World of Black
BLACK attacks Decade after he mistakes him for RX's Kotaro Minami. Decade refuses to fight and Diend appears to stop BLACK with Femme's power. They retreat and Decade continues his search for Guy. As Ryuki he fights him and saves a child, gaining BLACK's trust in the process and teaming up with him. They come across Geist and the newly recruited Schwarian, although Guy escapes through dimensional wall BLACK uses "King Stone Flash" to help Tsukasa get back to RX's world through the wall. Decade re-encounters the RX Kotaro and finds Guy. His card is revealed to be a Kamen Rider BLACK card but Diend uses it instead and the two Kotaros transform and fight Geist and Schwarian. Decade is able to get the Perfector but Diend steals it and runs away. Decade then destroys Schwarian with Agito's powers while the two BLACKs force Geist into retreating.

At the hospital Kaitoh hands over the Perfector to saying that there are other treasures that he has already taken from this world and there are always more to get from other worlds. Kaitoh takes his leave saying to Tsukasa to save his friend. Decade uses the Perfector to drain part of his life and implant it into Natsumi reviving her. Before leaving, Tsukasa tells Kotaro that Joe the Haze is helping his counterpart. But Kotaro is not saddened by it, knowing that Joe will be with him in spirit. The gang returns to the photo shop where the next world is waiting.

World of Amazon
When Tsukasa enters Amazon's world he immediately assumes the mantle of a baseball player and receives yet another card. He immediately sees that Dai-Shocker has taken over this world and is attacked by some of the monsters from different worlds. Amazon appears suddenly and helps Decade fight them but before a finishing blow could be done the people intervened convinced by Dai-Shocker that riders are destroyers forcing them to retreat.

They run into Kaitoh again where he explains his plan to steal Amazon's GiGi armlet's counterpart, the GaGa armlet which is unfortunately owned by the Ten-Faced Demon Llumu Qhimil, Dai-Shocker's designated ruler of the World of Amazon. Llumu sends out Masahiko Okamura to reveal the Rider's location by faking an attack by the Dai-Shocker foot soldiers and gaining their trust. Apollo Geist appears once more fighting Decade demanding his Perfector but Decade destroys it instead. The fight goes on until Masahiko steals the GiGi armlet after Dai-Shocker turns on him.

With Dai-Shocker now aware of where the Riders might go the gang goes to a nurse's office at Shocker School where Tsukasa finds a picture of Masahiko and his family before his father passed away. They are then driven off by Masahiko's older sister and the Dai-Shocker foot soldiers. They quickly come up with a plan to retrieve the GiGi armlet after Masahiko turned it over to them and was put up to be the first in the Humanity-to-Monster Project. He is saved by Tsukasa and Yusuke in disguise as foot soldiers and explains what happened. As they go out and retrieve the GiGi Armlet Amazon joins the fight against Llumu Qhimil, while Diend successfully obtains the GaGa Armlet during the battle. However this is short-lived as Tsukasa uses the armlet for himself through the use of his new card until giving to Amazon who delivers the final blow to Llumu with Super Big Slice. Amazon is then adopted into Masahiko's family and the gang returns to the photo shop to find Diend sitting there and he proposes that he go with them.

They accept and head into the next world which will be the site where all the riders are supposed to be; "The Rider War World". It is the same place that Natsumi saw when she had her dream about the war.

World of the Rider War
The Rider War World is Decade's undoing as he witnesses both Kamen Riders Blade and Kiva lead Rider armies against each other. Tsukasa and Yusuke try to keep both sides from killing each other and finding out the Fangire Queen, Yuki, marries Guy and becomes Super Apollo Geist. With this new enemy Tsukasa destroys Yuki with Ryuki Survive's abilities and the rest of the Fangire and Undead armies with help from Kazuma Kendate and Wataru. Unfortunately Super Apollo Geist uses his powers to make the worlds merge with Kazuma and Garren disappearing and Geist kidnaps Natsumi. He is then confronted by Kazuma Kenzaki, the original Kamen Rider Blade. Decade finally finds out why the worlds are merging and it is because of Decade himself. Kenzaki tranforms and assumes King Form, Decade is quickly defeated. Decade returns to the photo studio injured and finds out that every picture he took in the other worlds are completely blank because they are nearly gone. Decade heads out to follow Kivala and is confronted by Hibiki and Kiva who fight him. The two Riders were talked into helping Kenzaki save their own worlds. Kuuga saves Decade while he deals with Geist.

Decade catches up to Geist who has brought back all the different monsters he fought in the different worlds. Decade is quickly overwhelmed by too many enemies but with Kuuga, Hibiki, Kiva, and Diend he manages to drive the creatures back. Decade immediately fights Geist who has become very powerful with his super mode. Diend hands Decade his Kamen Ride Card and with the power of Diend two bursts annihilates Geist. Decade is exhausted and collapses with Kiva and Hibiki finally fading away because their worlds no longer exist. Decade is taken to the place where it all started the place where he met the original Wataru. Wataru explains that Tsukasa messed up his job and says that he and the others will fight him as he transforms into Kiva. Decade is again transported to the War world where the original Riders appear and Kuuga becoming Ultimate Form to fight Decade due to Kivala. Diend aims his gun directly at Decade's head at point blank range. With that the Rider War begins.

Movie War 2010
"I am the destroyer of all. I have accepted that."

- His answer when Natsumi confronted him

In Decade: Final Chapter, despite unwillingly as the Destroyer of Worlds, Tsukasa accepts his role and turns into Violent Emotion Decade destroying many Riders and turning them into cards. He is assisted by Yuriko Misaki who reminds Tsukasa of Sayo and can transform into Electro-Wave Human Tackle. He is confronted by Natsumi who has become Kamen Rider Kivala to stop his rampage. Before Tsukasa disappears after he voluntarily lets her destroy him, he gives Natsumi the Kamen Ride Cards and tells her that as long as people remember the Riders they will never disappear.

Natsumi and Kaito learn from Wataru Kurenai of Decade's role as the destroyer and connector of worlds, as Tsukasa would destroy the Riders he would connect the other worlds preventing their collapse and does anything he is needed for as a hero or a villain to finish the Rider's story. He himself however has no story and with his task complete Decade was gone forever. Despite this Natsumi finds a way to revive him through the use of a picture and the A.R. Riders' memories and Tsukasa is resurrected. Tsukasa and the gang along with other Riders fight against Super Shocker receiving more help from Kamen Rider Double who appear to know each other. With Double's Final Form Ride and Final Attack Decade destroys Super Shocker's most powerful and evil kaijin, Ultimate-D.

He is last seen with his friends posing for a picture after the battle while continuing his adventures across the A.R. Worlds.

Let's Go Kamen Riders
A mishap caused by the Greeed Ankh unintentionally altered the timeline which enabled Shocker to utilize the Core Medal to create the Shocker Greeed which defeated the Double Riders and seemingly erased the legacy of the Kamen Riders from history. In 2011, after Kamen Rider New Den-O's attempt to repair the damage, he along with Kamen Rider OOO and M-Ankh awaited execution. However, it was revealed the Double Riders had their brainwashing removed by a Shocker scientist.

The Double Riders joined with New Den-O and OOO to fight Shocker's forces, but were eventually defeated. When the order was given to kill everyone, V3 suddenly appeared, asserting that there were more than four riders. V3 was soon followed by all the other revived riders that came after him, as even though Rider history was changed, the people's memories haven't changed. Decade appeared after the three 90s riders and the first eight Heisei riders, fighting against Shadow Moon.

After the riders were united, they faced off against Shocker's Great Leader. Later, when joined by a force of extra riders, Decade and all the other riders got on their motorcycles and performed the "All Rider Break", ramming into the Rock Great Leader and defeating it once and for all.

Kamen Rider × Super Sentai: Super Hero Taisen


Tsukasa appeared in a movie alongside the Gokaigers in a Super Sentai meets Kamen Rider event, Kamen Rider × Super Sentai: Super Hero Taisen.

Doktor G resurrected and gathered all defeated Rider villains, recreating Dai-Shocker. He told Tsukasa that the Riders and monsters needed to destroy the Super Sentai to ensure the survival of the Riders, and, answering that, Tsukasa took control of the new Dai-Shocker, becoming its Great Leader again to battle the Super Sentai and also the Dai-Zangyack, a new union of Super Sentai villains led by the Gokaiger's Captain Marvelous. As the Great Leader of Dai-Shocker, Tsukasa apparently destroyed many Super Sentai teams, apparently leaving only GokaiRed and GokaiGreen alive, while Decade himself was seemingly the last remaining Rider. After he was wounded in his battle against GokaiRed, Doktor G used the opportunity to overthrow him and take control of the organization. The story about Riders needing to destroy Sentai to survive was a lie, and Doktor G was actually allied with Dai-Zangyack and using both GokaiRed and Decade to destroy the other heroes and afterwards kill the nominal leaders of the two organizations.

However, Tsukasa and Marvelous already realized that trap from the beginning before the war starts. The destruction of the Super Sentai actually just an act and the truth was, all the Super Sentai and Riders were just sent into a rift between dimensions. Tsukasa turned against Dai-Shocker and Dai-Zangyack, supported by all other Riders and Super Sentai. Alongside the Gokaiger, he killed General Shadow. In the end, he faced Doktor G, the man behind the new Dai-Shocker, and defeated him with the help of the Super Sentai team Goseiger, and Kamen Riders Ryuki and Blade. However, after being defeated, Doktor G was revealed to be Decade's old enemy, Narutaki, who escaped afterwards, and his real identity was left a mystery.

Super Hero Taisen Z
Decade appeared in Kamen Rider × Super Sentai × Space Sheriff: Super Hero Taisen Z. He joins with Kamen Riders Fourze, Meteor, Super-1 and Space Sheriff Gavan Type G, as well as the Super Sentai teams Choushinsei Flashman and Tokusou Sentai Dekaranger, as the three forces of super heroes confront Space Shocker.

World of Monsters
Decade was summoned along with OOO by the alternate version of Haruto, taking the children to the shop. Before taking the children away, he thinks that he has arrived in the World of Wizard, but Haruto tells him that he is mistaken. He is summoned again by Amadum to retrive back the Fourze Rider Ring from Haruto. He then teamed up with Haruto along with the Heisei Riders to fight Amadum and his monsters. However, Amadum was too powerful for the Riders as he takes their items from them, until Gaim arrives. Gaim easily beats Amadum up as the Riders regaining their items to transform into their final forms. After Amadum is defeated, and the Rider Rings gone, Tsukasa leaves to continue his journey, stating that Haruto and him will meet again.

Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai
Tsukasa will return in Kamen Rider Taisen. He is seen with box of donuts for Haruto.

Kamen Rider G
"You are the only one who can save this world."

- Decade encourages G.

At some point during his travels across the worlds, Decade came through a dimensional wall to a world which was home to Goro (Kamen Rider G), who was having a hard time fighting a Phylloxera Worm. Decade told G, who recognised Decade, that he was the only one who could save his world. Decade was soon followed by the Nine Heisei Riders through the dimensional wall behind him. Kuuga and Ryuki gave G their words of encouragement, then all ten Riders called out to him. With a boost in confidence, G got up and destroyed the Phylloxera Worm with his Swirling Rider Kick as the ten Heisei Riders vanished.

Kamen Rider Decade: The World of Tsukasa Kadoya ~The Garden Inside the Lens~
In the novel which is the reimagination of the TV Series, Tsukasa is generally the same personality wise. But his world is different from the world in Kamen Rider Decade: All Riders vs. Dai-Shocker movie. He has no sister and his parents live overseas. In the novel he’s described as a young NEET tired of his mundane life, the only thing he finds interesting is photography. He ends up stumbling upon an abandoned photo studio, inside he finds an old camera standing on a tripod. Tsukasa picks it up and peeks through the viewfinder. Through the viewfinder, Tsukasa sees a completely different world. Instead of a flimsy Eijiro Hikari that knocks down a backdrop, the group uses the camera to travel between worlds. In fact, Eijiro doesn’t even exist in the novel. The photo studio isn’t some ordinary photo studio that was just abandoned. It actually manifests itself in front of people that are tired of their own world and want to find a new world. Natsumi, Kaito and Narutaki, all found the photo studio in their own respective home worlds. In addition, Dai-Shocker, the evil organization itself never existed.

Tsukasa met Natsumi in the first unnamed world he traveled to. A world where monsters are attacking humans. Natsumi sees this and calls Tsukasa by the name ‘Decade’ and gives him the Decadriver, telling him he must transform. A confused Tsukasa goes along with it and becomes Decade for the first time. They travel to another world together and meet Daiki Kaito. He acts hostile towards Tsukasa, but still decides to follow the two on their travels.

With 6 A.R. Worlds discovered leaving Den-O, Kuuga and Kabuto's World unexplored, the trio arrived at The World of Den-O with Tsukasa’s clothes change into a doctor’s uniform as they arrive. Tsukasa meets Ryotaro, but his Imagin friends are missing. Tsukasa agrees to help him find them. The Den-O characters feel very off-character as their characteristics are different. Momotaros comes off as rather polite compared to his jerkish and self-centered TV counterpart, and actually refers to people by their real names instead of snarky nicknames. The Final Form Ride remains the same, as Tsukasa turns Den-O into Momotaros.

Arriving at Kuuga's World, Tsukasa is dressed as a painter and meets Yusuke Godai while having difficulties of remembering the name Decade and usually goes with “Kamen Rider Dickens.”

Despite being Kuuga’s world, Tsukasa doesn’t interact much with Godai.

Instead he meets a mysterious unnamed girl, with her sentences spoken in broken grammar. This girl approaches different men saying “Do you want me?” The girl is referred as Yuri after Tsukasa sees her holding a lily flower, yuri in Japanese. She asks the question to Tsukasa, but Natsumi doesn’t like it and uses her Laughing Pressure Point technique on him. Yuri takes a liking to Tsukasa and connects with him. Tsukasa says they are the same type of people, and relate to each other. But he reveals that he never really paid attention to her and never cared about her. From the start, Natsumi oddly suspects that Yuri is a Gurongi. This is never truly touched upon until the where Yuri reveals the truth and challenge the Riders into a fight. Her Gurongi group is not mentioned, but she’s described as a Moth, meaning she's of the Ba class of Gurongi. She causes people to explode by sticking moth scales from her wings on people. Decade and Kuuga defeat her together. Decade's Final Form Ride for this Kuuga is also different: while it retains the ability to transform Kuuga into the Kuuga Gouram, the Gouram is described as a rhinoceros beetle, despite it traditionally being a stag beetle, which is also the same insect Kuuga is based on. Godai gives Tsukasa a thumbs up as they leave.

They shortly move onto the world of Kabuto, where they meet Souji Tendou, still as arrogant and confident as ever, and considers himself as the strongest Rider ever. The group enters Bistro La Salle where Hiyori Kusakabe works. Hiyori sees Kaito and Tsukasa, dressed as ZECTroopers, claiming that the two of them ate without paying. Tendou hears this and is enraged. The three of them fight and Tendou actually beats them with only a pair of chopsticks. However, it turns out to be a pair of Worms that ate without paying. Tsukasa and Kaito are eventually captured by ZECT, only to have Tendou save them. Tsukasa thanks him and says that he never thanks people. Tsukasa starts respecting Tendou. For some inexplicable reason, Tendou has the Clock Up AttackRide Rider Card and gives it to Tsukasa after he realizes that he is Kamen Rider Decade. Tsukasa uses the Clock Up card as Kuuga, meaning the AttackRide cards aren’t restricted to their respective Riders in the novel. In the end, the Worms that impersonate both Tsukasa and Kaito have been defeated. As the fight is over the trio goes back to Tsukasa’s world.

Between all the traveling, a vampire has been attacking in Tsukasa’s world, leaving behind drained corpses. The group investigates and they find out that Narutaki is the vampire. Just like the group, Narutaki originally had his own homeworld, but abandoned it to find a new one. However, he’s been traveling for so long that his mind has been deteriorating and can barely remember who he really is. He was originally a human, but somehow in his journeys, he had lost his humanity. The Kamen Riders have a very pure energy that Narutaki seeks to consume: the Rider Cards. Thus, he sends Kaito to steal them for him. Kaito reveals his betrayal towards the team and gives Narutaki Tsukasa's 9 Heisei Rider Cards and Narutaki reveals his real form: a red-hued demon.

Kaito suddenly has a change of heart, and sacrifices himself to save Tsukasa. All hope seems to be lost; Tsukasa even uses a Diend card with the DecaDriver, which turns him into a cyan-hued version of Decade. However all seems hopeless, as he was badly overpowered by Narutaki and reverts into human form again. Natsumi, who had just realized that she has special powers all along, creates a special card with the 9 previous Heisei Riders on it. Tsukasa uses it, which summons the previous 9 Heisei Riders to do their finishers onto Narutaki. They then turn into cards and attached themselves onto Decade, turning him into Final KamenRide: Tsukasa, which can be described as Complete Form without a K-Touch. Tsukasa then finishes off Narutaki via a Rider Kick. In his dying words, Narutaki wanted to destroy all worlds and then create his own ideal world. He dies looking at Natsumi, knowing that she had the power to do what he wished for.

With the crisis over, Tsukasa returns to his world and Natsumi decides to go with him and live in his world. When they return, Tsukasa finds an article where it says Tsukasa's world's version of Natsumi died after committing suicide due to worldly troubles.

A few decades later, an unchanged young Kaito revives and reappears in front of an elderly Tsukasa. Kaito tells him it’s time to visit Natsumi’s world. There they are greeted by a young Natsumi, and Tsukasa finds himself as a young man again.

Kamen Rider Battride Wars
Kamen Rider Decade appears as a Main Rider in the video game Kamen Rider Battride Wars, which unites the riders of the Heisei era from Kuuga to Wizard.

In the game, Decade is the only character to picked 3 from 9 main pre-Decade's Heisei KamenRide Forms (mostly their main forms), in which Decade able to access his normal sword attacks with the other Kamen Rider's ground special attacks. While performing a finishing moves (Final Attack Ride) in some KamenRide Forms, it will revert back to Decade. His ultimate form, Complete Form can access an ultimate attacks anytime depends on the some KamenRide to be used on. Like Blade, normal Beast and Wizard Infinity Style, Decade can perform a normal aerial slash twice.

Decade's special attacks are:


 * Attack Ride:
 * Decade: Blast (rapid tap), Slash (three times)
 * Kabuto: Clock Up (Special 1: followed with dash slashing. Limited until Clock Over when no attacks (mainly normal to special 1 chains) or/and recently deactivated while being hit, using special 1 spam attacks or special 2 (Clock Up like special radial attack))
 * Hibiki: Ongekibou - Rekka, Onibi
 * Ryuki: Strike Vent, Guard Vent (first used)
 * Final Attack Ride: Dimensional Kick (for Complete Form is an Enchanted version of this move)

Rider Powers
He mostly appeared as Kamen Rider Decade. Only in Episode 14 of Kamen Rider Decade, he briefly transformed into Kamen Rider Den-O Sword Form after possessed by Momotaros.

Kamen Rider Decade's ending theme is entitled "Ride the Wind".

Decadriver
Tsukasa transforms into Decade through the use of the Decadriver belt that is based around the Rider Cards. By inserting a card into the Decadriver, Decade can invoke the cards' abilities. In Complete Form, the Decadriver is moved to the right side of his belt where Decade inserts his Final Attack Ride Cards and activates them by touching the Decadriver's window.
 * Change announcement: KAMEN RIDE
 * Form Change announcement: FORM RIDE
 * Attack announcement: ATTACK RIDE
 * Rider Form change announcement: FINAL FORM RIDE
 * Final attack announcement: FINAL ATTACK RIDE
 * Decade Complete announcement: FINAL KAMEN RIDE

Ride Booker


Decade's primary weapon is the Ride Booker (ライドブッカー) which has three modes: the default Book Mode (ブックモード), which is placed on the left side of his belt and holds the Rider Cards that Decade uses in his arsenal, Gun Mode (ガンモード) which can be used to execute the Dimension Blast (ディメンションブラスト) finisher and Sword Mode (ソードモード) which can be used to execute the Dimension Slash (ディメンションスラッシュ) finisher.

When fighting Gyūki, Decade briefly fought as Ryuki with a red bullfighting cape adorning the blade of Sword Mode. In either Mode, Decade primarily uses the Ride Booker in the place of the Heisei Kamen Riders' signature weapons, regardless if in the form of blades or firearms, unless it is weapons with a nature like that of Kuuga's, Agito's, or Kiva's.

K-Touch


The Final Kamen Terminal K-Touch (ファイナルカメン端末ケータッチ) is a special touchscreen cell phone. Originally from the World of Negatives in the possession of the Dark Riders, the K-Touch was designed to attach onto the Decadriver replacing the card slot, which is moved to his right hip, allowing Decade to transform into Complete Form. In this form, Decade can still use his Ride Cards by inserting them in the card slot and touching its visor, allowing Decade to summon the powers and weapons of the ultimate form of any of the previous Kamen Riders. When a Rider is summoned, the cards on Complete Form's chest and shoulders change to match the Rider's specific Kamen Ride card and the summoned Rider copies Decade's motions. When activating the K-Touch's functions in Complete Form, any of the Nine Heisei Riders present will be transformed into their most powerful form. In Hyper Battle Video, K-Touch seemed has a function to summon all previous Heisei Riders in their respective ultimate form without Decade pressing the buttons of the K-Touch.

Final Kamen Ride
In Kamen Rider Decade: The Last Story, Kuuga and Den-O's options are changed to Rising Ultimate (ライジングアルティメット) and Super Climax (スーパークライマックス) respectively, including the card on Decade Complete Form's chest armor.
 * Ryuki Survive: Summons Kamen Rider Ryuki Survive, armed with the Drag Visor-Zwei. Using the Ryuki Final Attack Ride Card allows Decade to execute a Burning Saber-style attack alongside Ryuki Survive.
 * Faiz Blaster: Summons Kamen Rider Faiz Blaster Form, armed with the Faiz Blaster. Using the Faiz Final Attack Ride card allows Decade to execute a Photon Buster-style attack alongside Faiz Blaster Form.
 * Kabuto Hyper: Summons Kamen Rider Kabuto Hyper Form. Using the Kabuto Final Attack Ride card allows Decade to execute a double Hyper Kick or a Maximum Hyper Cyclone (armed with the Perfect Zector in Gun Mode) alongside Kabuto Hyper Form. Also used by default form Decade to transform into Decade Kabuto Hyper Form in SIC Hero Saga, World Of Stronger to fight Stronger Charge Up Form, but was defeated. Also used again by Decade Complete to fight Stronger Charge Up Form but unfortunately beaten by Stronger Charge Up' Super Stronger Electric Kick.
 * Kiva Emperor: Summons Kamen Rider Kiva Emperor Form, armed with the Zanvat Sword. Using the Kiva Final Attack Ride card allows Decade to execute a Final Zanvat Slash-style attack alongside Kiva Emperor Form.
 * Hibiki Armed: Summons Kamen Rider Armed Hibiki, armed with the Armed Saber. Using the Hibiki Final Attack Ride card allows Decade to execute an Ongeki Ha: Kishin Kakusei-style slash alongside Armed Hibiki.
 * Den-O Liner: Summons Kamen Rider Den-O Liner Form, armed with the DenKamen Sword. Using the Den-O Final Attack Ride card allows Decade to execute a Train Slash-style attack alongside Den-O Liner Form.
 * Blade King: Summons Kamen Rider Blade King Form, armed with the King Rouzer. Using the Blade Final Attack Ride card allows Decade to execute a Royal Straight Flush-style attack alongside Blade King Form.
 * Agito Shining: Summons Kamen Rider Agito Shining Form, armed with the Shining Caliber. Using the Agito Final Attack Ride card allows Decade to execute a double Shining Clash-style attack alongside Agito Shining Form.
 * Kuuga Ultimate: Summons Kamen Rider Kuuga Ultimate Form. Using the Kuuga Final Attack Ride card allows Decade to channel flames from his hand alongside Kuuga Ultimate Form. This K-Touch option is not used in the television series but however appeared in Kamen Rider Battride War.

Machine Decader


The Machine Decader (マシンディケイダー) is Decade's personal Honda DN-01. Like Decade himself, the Decader can assume the form of the respective Rider's Machines.The bike can also transforms into previous Rider Machines as it exhibits this ability when Decade (as Faiz) transforms the Decader into the Auto Vajin and Side Basshar (as Decade's Violent Emotion).

Decade Bazooka


The Decade Bazooka (ディケイドバズーカ) is a firearm weapon of Decade's that is only seen in the Kamen Rider Decade: Protect The World of Televi-Kun Super Adventure DVD. To tie in with the DVD, the Decade Bazooka is constructed from cardboard punchouts and glue by Yusuke Onodera, much like prizes given out with issues of the Televi-Kun magazine. Though it expands from its original toy-like size to the size of a full bazooka when given to Decade, it clearly remains a cardboard prop, though this does not impede its functionality as a weapon.

Etymology
Tsukasa's surname translates to Gate (門) Arrow (矢) which reference the Dimensional walls he is associated with, while his given name means Gentelman (士).

Portrayal
Tsukasa Kadoya is portrayed by Masahiro Inoue (井上 正大), who reprised his role in Kamen Rider × Super Sentai: Super Hero Taisen and in episode 52 and 53 of Kamen Rider Wizard. In his appearance in OOO, Den-O, All Riders: Let's Go Kamen Riders, Decade was voiced by an unidentified voice actor. While disguised as Kamen Rider Ichigo in Kamen Rider × Super Sentai: Super Hero Taisen, he is voiced by Tetsu Inada (稲田 徹). In Kamen Rider × Super Sentai × Space Sheriff: Super Hero Taisen Z, Kamen Rider Decade's voice was provided by Katsuhiro Suzuki (鈴木 勝大), who plays Hiromu Sakurada/Red Buster in .''

As Kamen Rider Decade, his suit actor was Seiji Takaiwa (高岩 成二), who has been the suit actor for the majority of leading Kamen Riders in the Heisei era (except Kuuga and Hibiki). In Super Hero Taisen, his suit actor was Jun Watanabe (渡辺 淳).

In Popular Culture
Haiyore! Nyarko-san episode 3 contains an extended reference to Decade in the rooftop lunch scene. Cuuko teases Nyarko with a cake from the legendary space bakery DK-Do, owned by a man named D. Endo. The cake is said to be a limited 10th anniversary special production, and is modeled on the Decadriver; additionally, when Nyarko explains about the bakery to Mahiro, its name appears in black and magenta stripes, while D. Endo's is represented with black and cyan. Later on, Nyarko transforms her pet Shantak-Bird into a motorcycle, with her remarking "This may tickle a bit. Heck, it'll only hurt for a moment;" in the light novels, this Final FormRide-style forced transformation is explicitly stated to be one of Nyarko's unique special powers.
 * Additionally, Nyarko's favorite television show is Iron Striver, a tokusatsu show made on Earth that serves as an obvious homage to the Kamen Rider franchise.  A brief segment of the show seen in the OVA episode "How to Defeat a Kind Enemy" shows it to mostly be based off of Decade, with the main character physically resembling Tsukasa and using with a card-reading belt that forms the word "StriveRide" to transform. Said segment also features direct quotes from Decade, with Striver telling the villains "Bring it on! I'll destroy everything!"

Appearances

 * Kamen Rider G (voice only as Decade)
 * Kamen Rider Decade: all episodes
 * Cho Kamen Rider Den-O & Decade Neo Generations: The Onigashima Warship
 * Samurai Sentai Shinkenger Act 21: The Father and Son Bears
 * Kamen Rider Decade: All Riders vs. Dai-Shocker
 * Kamen Rider Decade: All Riders Super Spin-off
 * Kamen Rider × Kamen Rider W & Decade: Movie War 2010
 * OOO, Den-O, All Riders: Let's Go Kamen Riders
 * Kamen Rider × Super Sentai: Super Hero Taisen
 * Kamen Rider × Super Sentai: Super Hero Taihen – Who’s the culprit?!
 * Kamen Rider Wizard
 * Episode 52: The Kamen Rider Rings (voice only as Decade)
 * Finale: Neverending Story