Koichi Sakakibara

Koichi Sakakibara (榊原 耕一Sakakibara Kōichi) is the original Ryuki before Shinji Kido that appeared in 13 Riders TV Special. In the original TV series, his name was mentioned in first 2 Episodes of Ryuki.

Fictional character biography
He is a man who lived in an apartment where Shinji found a Card Deck that led him to become Kamen Rider Ryuki. He disappeared prior to the start of the series, possibly eaten by Dragreder.

In the 13 Riders TV special, Sakakibara is the original Ryuki. He saved Shinji but as he could no longer go on due to the severity of his injuries, he passed his deck on to Shinji as he dissolved inside the Mirror World. After Koichi faded, Shinji became Kamen Rider Ryuki and tried to prevent the other Riders from fighting as his way to thank Sakakibara.

Kamen Rider Ryuki
Unlike Shinji, he only shown to be assume normal standard form in 13 Riders TV Special. ​This is Ryuki's standard form that he had throughout most of the series, obtained once he forms his contract with Dragredder. A "balanced" Rider with equally powerful melee and far-range fighting capabilities, he uses the Drag Visor gauntlet on his left forearm to use Advent Cards.
 * Height: 190 cm
 * Weight: 90kg
 * Punching Power: 10t (AP: 200)
 * Kicking Power: 20t (AP: 400)
 * Maximum Jump Height: 35m
 * Maximum Running Speed: 72km/h
 * Sight and Hearing: 15km radius

Trivia

 * Koichi's actor, Keiichi Wada, previously portrayed Ryo of the Heavenly Fire Star (RyuuRanger) from Gosei Sentai Dairanger, a Red Sentai Warrior that shares the same theme with Ryuki: both controlled Asian dragons who can breathe fire.
 * Along with Yūta Mochizuki who had played Kouji Segawa (Kamen Rider J) and previously Yamato Tribe Prince Geki (TyrannoRanger), Koichi Sakakibara can be counted as the second time a main Kamen Rider was played by the actor who also portrayed a Red Ranger in Super Sentai series.
 * He has the same name with the protagonist of the anime Another, Kouichi Sakakibara.