The 10th Anniversary Kamen Rider starting in 2009 he will be able to transform in all 9 previous Heisei Kamen Riders.
Tsukasa Kadoya doesn't know who he was and how he came to be... But after Wataru Kurenai came to him saying that all 9 previous rider worlds where going to merge with his and that he must destroy all Kamen Riders he knew something was wrong with his life. Suddenly worlds started bumping into each other and he`s companion Natsumi ran through several familiar looking worlds till she ended up in Tendou`s world where she found the Decadriver and as she found it she ran up a path till a dimensional wall stopped her from getting to Tsukasa and behind her a Worm appeared she had no choice but to give Tsukasa his belt which he used to transform into Decade. Decade`s Rider Form stats:
The cards Decade uses for his forms: He has shown to be able to change in the forms of several fellow Kamen Riders through KamenRide cards and he`s also able to transform into all they`re basic forms trough FormRide cards, for the attacks and special abilities of those riders he uses AttackRide cards and finally we get the Final FormRide cards these allow Decade to change another Rider into a weapon or a allied beast, in combo with these Decade uses the Final AttackRide cards for a finisher Decade can also use these cards when he is in that certain Rider`s form to activate a finisher as he showed in Episode 10 when he used the Final AttackRide card to preform Blade`s personal RiderKick.
In the World of the Negatives, Tsukasa obtained the K-Touch which he uses to transform himself in to Kamen Rider Decade Complete form. This for allows him to call upon all of the 10 main Heisei Riders in their Ultimate forms and double their power in a mimic type of way. As the Riders who he calls upon mimic every move he does