Kamen Rider Ryuki
is a 28-year-old man who lives in an apartment where Shinji found a Card Deck that leads him to become Kamen Rider Ryuki. He disappeared prior to the start of the series, eaten by Dragreder. In "Kamen Rider Ryuki Special: 13 Riders", Sakakibara is the original Ryuki before the latter passes his deck to Shinji as he dissolves inside the Mirror World.