Kintaros (キンタロス Kintarosu) is the third Imagin that gives Ryotaro Nogami the ability to become Den-O, with Kintaros making up Kamen Rider Den-O (仮面ライダー電王 Kamen Raidā Den'ō)'s Ax Form.
Originally, Kintaros entered a retired karateka named Masaru Honjō, whose vision of Kintarō gave the Imagin his "bearish" look, as he attempted to master karate to give Masaru the "ultimate karate" so he can settle things with Shinji Kikuchi. However, unlike the Rhino Imagin who formed a contact with Kikuchi, Kintaros has no intention of disturbing the timestream and only wants to protect Masaru. Seeing the good side of him as he fulfilled his contact with Masaru to aid in holding off the Rhino Imagin at the cost of his well being, Ryotaro allows a dying Kintaros to enter him to the shock of both Momotaros and Urataros. Kintaros is also almost thrown out of the Den-Liner for disrupting the flow of time, but is allowed to stay as the change in the past negated the present events that led to his banishment.
During the events of Kamen Rider Den-O: I'm Born!, Kintaros possesses the Ryotaro that Yuto brought to the Edo era to aid in the Climax Scene. But this results in him fading from existence were it not for Ryotaro's feelings condensing his remains into the K-Taros, restoring him to normal while allowing Kintaros to form the left shoulder armor of Den-O's Climax Form until his synch with Ryotaro was negated. However, his power is now accessed in the DenKamen Sword's Kin-Ax Mode. On his own, Kintaros can perform Dynamic Chop, ranging from either a jump from a high point to a full-circle swing attack.
When the Imagin Army invades both the past and the present, Kintaros saves Den-O Liner Form from the overwhelming forces as he gives him a model of Kintarō and three other items to grant Ryotaro's wish, the boy's New Year's resolution for him and the Tarōs Imagin to still fight together. With his contract fulfilled and no longer allowed to ride the Den-Liner, Kintaros destroys the first Imagin wave as Den-O Ax Form before holding his own against the following waves without the Den-O Belt while Ryotaro escapes back to the present to save Airi, leaving Kintaros in June 6, 2000, to fend off the endless hordes.
However, Kintaros's granted wish enables the other Tarōs to have physical forms within normal space-time as well. Kintaros is retrieved by Naomi for the final battle as he battles the Death Imagin as Den-O Ax Form, his power utilized by Sword Form for the final blow. Kintaros then joins the Den-Liner Police, helping in the fight against Negataros, and later assumes Ax Form again (on his own, with a pass) during the epic battle against the revived Imagin alongside all the Rider forms.