Tsukasa Kadoya (門矢 士, Kadoya Tsukasa?, portrayed by Masahiro Inoue[1]) 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" (悪魔, akuma?), 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 have some fate befall them, be it death or otherwise. As Tsukasa travels between dimensions, his clothing changes to suit a specific role in the Rider's World, including some accouterments similar in color to his camera and Decade's armor. 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 Grongi language in the World of Kuuga and his enrollment as a student in the World of Faiz. He has also mentioned before that he is capable of doing anything except take photos.

I Like His Act And Role... Helping People in His Egoist Way...hahaha.... Cool...