|“||Curse you, Decade!!||„|
Narutaki is a mysterious man and a recurring antagonist in Kamen Rider Decade.
Referring to himself as a prophet, Narutaki firmly believes that Tsukasa Kadoya, should not exist in any world and uses the other Kamen Riders to kill for him. He also talks Natsumi into doing the deed herself as the upcoming Rider War will awaken Tsukasa's true nature as Decade.
After Decade defied his premonitions of doom in the previous nine worlds, Narutaki decides to personally deal with him in the World of Hibiki by summoning a Bakegani, revealing to Natsumi that Tsukasa's actions are actually destroying the worlds rather than saving them as they were told, and that only she can stop the madness now.
In the World of the Rider War, he asks for Tsukasa's help to stop Apollo Geist from speeding up the destruction of all worlds, but this doesn't change his belief that Tsukasa is the true cause of the destruction, or his desire to see Tsukasa stopped. Soon after, Narutaki becomes Colonel Zol to join the Super Shocker organization to take advantage of the Kamen Riders' defeat to conquer the worlds. However, when Doras fell from the Super Crisis Fortress and knocks him out of his way, he reverts back to Narutaki and curses Decade for causing a new calamity born from the Neo Organism's antics before running off.
Nrutaki resurfaces a few years later as Doktor G, a general of the revived Dai-Shocker and right hand to Tsukasa. However, he forms a alliance with the villains of the Dai-Zangyack as both groups trick their leaders into killing off their enemies for them. However, Tsukasa and Marvelous played the villains and made their move as Doktor G and Silva attempt to create Big Machine. In the battle that followed, Doktor G overpowers Decade and his Kamen Rider allies as Kani Laser until the Goseigers give Decade, Ryuki, and Blade their defense Gosei Cards to weaken Kani Laser to finish him off with a triple Rider Kick. However, reverting to his true form, Narutaki tells Decade that his journey will continue and departs to another world. Narutaki later appears in front of Kouta and Right as he gives Kouta a Rainbow Pass and before leaving without further explanation about an outcome Rider War between each Riders from two different eras.