Kamen Rider Decade: World of Shinkenger

Kamen Rider Decade: Shinkenger World is a teamup with Samurai Sentai Shinkenger and Kamen Rider Decade. It is the first crossover between Shinkenger and Kamen Rider. The crossover occured across Kamen Rider Decade episode 24: The Arrival of the Samurai Sentai (見参侍戦隊, Kenzan Samurai Sentai), and episode 25: Heretic Rider, Go Forth! (外道ライダー、参る！, Gedō Raidā, Mairu!), along with Shinkenger Act 20, The Ebi Origami's Transformation, and Act 21, The Father and Son Bears.

The Arrival of the Samurai Sentai
Arriving in the new world with a strange card in hand, Tsukasa finds himself in the costume of a kuroko before running into Daiki who just stole a squid-like artifact. Daiki mentions that this world is not like the other A.R. Worlds before running off prior to the appearance of mysterious red fish-like monsters. Tsukasa is about to transform before several other Kuroko show up along with five young men and women who transform into the Shinkengers to fight drive them back into the Sanzu River. Yusuke and Natsumi return to the Hikari Studio after losing sight of Tsukasa, with Natsumi worried about not being in an A.R. World. Tsukasa, however, is at the Shiba Clan household, listening in on a discussion between Takeru Shiba and his caretaker, Hikoma Kusakabe, over the latter's need to go to the hospital. Elsewhere, sushiman Genta Umemori catches up to Daiki, ready to fight him for stealing the Ika Origami. Both transform, and Diend summons both Kamen Riders Scissors and Raia to fight Shinken Gold. Unbeknownst to them, Bony Shitari sends the Ayakashi Chinomanako to investigate Diend out of dread of his appearance. Chinomanako arrives just as Shinken Gold takes out the summoned riders and steals the Diendriver from Daiki, knocking out Shinken Gold in the process. Chased by the Ayakashi, Daiki makes his way to Tsukasa who laugh at the irony before using Den-O's power as Decade to fight Chinomanako. The Ayakashi escapes at the last minute, and is suddenly compelled to use the Diendriver, inserting the Diend Kamen Ride Card and shooting it above him. Transformed into a monstrous version of Kamen Rider Diend, Chinomanako summons a mass of Nanashi to attack the mortal realm to Narutaki's horror of the newly born abomination.

Heretic Rider, Go Forth!
After Tsukasa reveals himself, Takeru realizes that Tsukasa is the "Decade" Narutaki warned him about. Before the two can fight, Narutaki arrives to tell Tsukasa he is to blame for the terror brought unto the world by the Ayakashi Chinomanako who now has the powers of Diend, and that the only way to save the worlds he entered if he ceases to exist. After Takeru takes out the Nanashi and drives off Chinomanako as Shinken Red, Genta attacks Tsukasa believing that he is in league with Daiki until Natsumi takes him to the Hikari Studio, where Hikoma Kusakabe is hiding. When the other Shinkengers arrive, Daiki uses their fears to cause a fight to break out and escapes with Genta not far behind, leaving Natsumi to break it up before going to a room where all of Tsukasa's photos are kept. When Chinomanako attacks again, Genta ends his chase and contacts the Shinkengers who go off to fight the Ayakashi Rakider alone. Tsukasa, troubled by Narutaki's words, stays behind with Yusuke trying to convince him to help before he goes off on his own. By then, Hikoma comes forward and convinces Tsukasa to continue to find his place, regardless of what Narutaki has said to him. Tsukasa joins the battle just as Chinomanako and his summoned Eagle Undead and Moose Fangire have overpowered the Shinkengers and Kuuga. Decade and Shinken Red fight Chinomanako, who has summoned Kamen Rider Blade to fight with him. The other Shinkengers and Kuuga manage to destroy the Eagle Undead and Moose Fangire as Decade becomes Complete Form and uses the powers of Blade King Form to attack Chinomanako. Using the Blade Final Form Ride Card, he transforms Chinomanako's Blade into the Blade Blade before switching weapons with Shinken Red to use active Rekka Daizantou Attack Ride Card to destroy Chinomanako, saving the world. Daiki shows up just in time to snatch the Diendriver back, only to be thwarted by Shinken Gold who forces him to give back the Ika Origami in exchange for the Diendriver, and then everyone goes their separate ways. 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.

Kamen Rider Decade

 * Tsukasa Kadoya (Kamen Rider Decade)
 * Natsumi Hikari
 * Eijiro Hikari