is a Japanese tokusatsu series that serves as the 19th installment in the Kamen Rider franchise and the 10th entry in the Heisei era. These characters exist amongst various iterations of reality within the series referred to as an A.R. World (Another Rider's/Alternate Reality World).
Hikari Studio
The is the photography studio that the Hikari family owns and where Tsukasa Kadoya develops his photographs. The various backdrops located in the studio allow it to transport its occupants to a multitude of parallel worlds. Its interior and exterior automatically transform to blend into the surroundings when moving across dimensions.
Tsukasa Kadoya
is a hypocritical and self-righteous man whose had no memory of his past, having a strong desire to "catch the world" using his photos. But the fact that Tsukasa's photo never develop well hint him to be from another world while unaware of the effect as prelude of a convergence of the alternate dimensions known as A.R. Worlds that threaten the main universe. Approached by Wateru Kurenai while acquiring the DecaDriver, Tsukasa begins a journey to other Kamen Riders' worlds to save the prime universe as Kamen Rider Decade. But as Decade, besides exhibiting in-depth knowledge of a world he is in, Tsukasa faces both threats that endanger the worlds and the interference of Narutaki who spreads rumors of him as a . But Tsukasa soon understands what Narutaki meant upon learning that he was originally the Great Leader of the Dai-Shocker organization which sought to take all dimensions and that his true mission is to destroy the other A.R. World Riders and their worlds. Tsukasa undertakes the role, sealing the A.R. World Riders in cards before being fatally wounded by Natsumi when she becomes Kamen Rider Kiva-la. His death being the catalyst for the restoration of all the A.R. Worlds and those who died during the Rider War, Tsukasa is revealed by his friends' memories as he, the revived Kamen Riders, and Kamen Rider W defeat newly formed Super Shocker and the revived Neo Organism. Afterwards, Tsukasa and his friends return to the Hikari Studio to continue in their journey across the A.R. Worlds.
Tsukasa uses the belt and to become Kamen Rider Decade, using to assume the form of a Kamen Rider and access their arsenal via the , , and . He can also use the to transform another Kamen Rider into a new form for a combo attack. During the events of Kamen Rider × Kamen Rider W & Decade: Movie War 2010, Decade becomes a destructive embodiment of himself known as before he was defeated by Natsumi as Kamen Rider Kiva-la.
While in the World of Negatives, Tsukasa acquires the touchscreen cell phone that attach onto the DecaDriver, replacing the card slot which is moved to his right hip, to enable Decade to assume his true . In this form, he can manipulate the power of other Riders' final forms, whom he can summon through the K-Touch, for powerful combo attacks. A stronger variation of the form is which has the Kamen Ride Cards of his predecessors' ultimate forms on his armor.
During the events of Kamen Rider × Super Sentai: Super Hero Taisen, Narutaki restores Dai-Shocker and enters an alliance with the Super Sentai villains that formed the Dai-Zangyack. Tsukasa, feigning to resume his role as Dai-Shocker's leader, declares war on the Super Sentai and battled Captain Marvelous of the Gokaigers to an epic standstill before faking their deaths to catch the villains off guard once they reveal their actual plan to take over the world. Tsukasa also appears in the Kamen Rider Wizard finale when summoned by the sorcerer Amadum to attack Haruto, only to aid his successor defeat the villain before departing for points unknown.
Tsukasa later returns during the events of Kamen Rider Zi-O to help change Sougo Tokiwa's destiny and ensure he becomes a hero instead of a tyrant using the belt to access the powers and forms of his successor Riders up to Kamen Rider Zi-O. In the special episode Rider Time: Kamen Rider Zi-O vs. Decade: Seven Zi-O!, he gains an upgraded version of the K-Touch that allows him to transform into an upgraded version of his Complete Form called , which allows him to access the powers of all Riders' final forms from Kamen Rider Kuuga's Ultimate Form to Kamen Rider Zero-Two.
Tsukasa Kadoya is portrayed by . As a child, Tsukasa is portrayed by .