|[[Image:Template:SeasonAbbrevation_Ryotaro Nogami.jpg|220px|center|Ryotaro Nogami]]|
|Series:||Time Sentai Liner|
|Number of Episode|
Ryotaro Nogami (野上 良太郎, Nogami Ryōtarō) is a young man with a lot of bad luck. When he first appeared, he managed to lodge himself in a tall tree while on his bike after losing control and going up a fallen sign. He has even placed a name tag in his wallet so it can be returned to him when it is stolen. Despite his hardships, Ryotaro will help anyone in need if he has the ability to do so. He refuses to accept self-sacrifice as the only means to protect others.
As a Singularity Point, he can resist the control of an Imagin contracted to him, among other things, as long as he's conscious. Due to this unique attribute, he was given the power to become Den-O, a Kamen Rider who protects the timeline from the Imagins' actions. As Ryotaro continues on his mission, he meets more Imagin, each taking his body and using it as their own for the duration of their possession. Each of his personality changes affect the color of his eyes and some strands of his hair, changing its color to match the Imagin.
- When possessed by Momotaros, Momo is in Ryou's body. His hair spikes up slightly with a single red streak and he gains more muscular definition and the physical strength to go with it.
- When possessed by Urataros, Ura is in Ryou's body with the right words to woo women and convince almost anybody. His hair is straight and calm and has a single blue streak going through it. He also wears a pair of black rimmed eyeglasses.
- When possessed by Kintaros, Kin is in Ryou's body. His hair grows such that he has a ponytail with a golden yellow streak through it. However, his increased strength often results in self-injury and clumsiness.
- When possessed by Ryutaros, Ryuu is in Ryou's body, incorporating dancing into everything he does. He grows one long purple and black streak of hair and is always seen wearing a brown cap. His reckless personality infests itself upon Ryotaro, and usually causes him to destroy whatever is around if he gets out of control. One such incident occurred during the events of Climax Deka when R-Ryotaro arrested everyone who he thought looked suspicious and was part of the "Evil Organization" advertised by Negataros.
- When possessed by Sieg, though they never forged a contract, Sieg is in Ryou's body. His hair is styled in cornrows and has several white highlights with one longer white and black lock on the left side of his face, and a white feather boa appears around his neck.
- While Yuto was removed from time, Ryotaro gained a contract with Deneb, Deneb is in Ryou's body. His hair grows out past shoulder length with two locks of hair on each side of his head. On the right side, the lock is a neon green with a darker green streak within it.
The son of Shinichi and Kayoko Nogami, Ryotaro lost his parents while in childhood with his older sister Airi caring for him along with their grandmother, making visits to the closed down Milk Dipper that his parents owned. He kept the only picture of their parents with them until he lost it, feeling regretful of it since. He and Airi eventually re-opened the Milk Dipper with the aid of his sister's fiancé. However, when Airi's fiancé mysteriously disappeared a month before the wedding, resulting in Airi's current amnesia of everything related to the man, Ryotaro dropped out of high school to help his sister at the Milk Dipper, being burdened that his sister made herself forget about the fiancé and attempts to make sure she is not reminded and be hurt.
When he finds the Rider Pass, he unwittingly becomes the protector of time and space known as Kamen Rider Den-O, fighting the Imagin who traveled to the year 2007 to grant wishes and travel further into the past to change the future to their liking. As he is a Singularity Point, he is immune to the effects of changes to the past, and he can also resist the temptations of an Imagin, as seen with the hotheaded Imagin he named Momotaros, whose contract provides Den-O with a fighting form. He is assisted by the Singularity Point Hana as well as the crew of the Den-Liner, a train that allows him to traverse time in pursuit of Imagin. They are the mysterious Owner of the Den-Liner and the dining car's waitress Naomi. Along the way, he becomes contracted to other Imagin who give him the ability to access three of Den-O's other forms. They are the lying Casanova Urataros, the herculean and narcoleptic Kintaros, and the childish yet strong Ryutaros.
Ryotaro later identifies a mysterious man who has been following him through the past as his sister's fiancé Yuto Sakurai, but then meets a young man who calls himself Yuto Sakurai and his Imagin contract Deneb, the team that can become Kamen Rider Zeronos. Upon meeting Yuto, he begins to learn more about the nature of time and the Imagin, and is told by Yuto that protecting people is not as important as protecting time. Ryotaro does not believe this and feels that the two are one in the same, and he will do so, despite his own weaknesses.
Ryotaro also briefly meets the Swan Imagin Sieg who allows him to access another form, and later the evil Kamen Rider Gaoh who hijacks the Den-Liner to travel to the past to obtain the the Gaoh-Liner, wipes Ryotaro's memory of being Den-O for a while, meeting his past self as a result, until Gaoh takes him to the Tokyo of December 26, 1988, the day Ryotaro Nogami was born, in an attempt to erase him. To defeat him, Yuto travels in time to pick up three other incarnations of Ryotaro for Urataros, Kintaros, and Ryutaros to possess and aid Ryotaro in the "Climax Scene", destroying the Gaoh-Liner and defeating Gaoh. In the process, while getting to see his parents firsthand, Ryotaro learns how "people's memories are time".
Upon his return to the present, Ryotaro learns that because he retains only the memories of fighting Gaoh as Sword Form while his past selves are incapacitated, he has no memory of fighting as Rod, Ax, or Gun Forms. This causes Urataros, Kintaros, and Ryutaros to all dissolve into sand, from which Ryotaro's feelings manifest the Climax Cellphone K-Taros. This restores the three lost Imagin, and gives Ryotaro access to the stronger Den-O Climax Form.
When Ryotaro's actions cause the Junction Point to manifest, his sync with the Tarōs starts to dissolve as a side effect, forcing him to fight as Plat Form. However, solving the crisis in advance, the Tarōs use their powers to create the DenKamen Sword so Ryotaro can assume the powerful Den-O Liner Form so he can fight on his own. Shortly thereafter, he meets the Singularity Point Kai, who seeks to make the Imagin's future the true future, by seeking to destroy the Junction Point, who is later found to be Ryotaro's sister Airi. As a result, Ryotaro falls into a trap set up by Kai to keep him from Airi, with Kintaros and Urataros sacrificing themselves so Ryotaro can return to the present. In the process, Ryotaro learns that his missing memory is tied to the true identity of the one who will ensure that the flow of time and space leads to the future without Imagin: his niece who is revealed to be Hana/Kohana.
After the final battle is over, Ryotaro is saddened by the supposed loss of the Tarōs, only to find out that they and Sieg, still existing due to their memories together, are hiding in a ditch attempting to surprise him. Ryotaro is overjoyed that they are all still alive and celebrates happily. With his mission to protect time from Kai and his Imagin finished, Ryotaro relinquishes his Rider Pass back to the Owner of the Den-Liner, thanking everyone for what they have done for him. As he rides his bike back to the Milk Dipper, he is greeted by all of the riders of both the Zero-Liner and the Den-Liner who bid him a final farewell before departing into the time stream. Ryotaro smiles as they pass by, knowing that he will meet them again someday in the future.
Later, when an Imagin named Negataros steals the Rider Pass from Owner, Ryotaro joins the newly formed Den-Liner Police to stop Negataros and his "Evil Organization", succeeding thanks to the aid of Kamen Rider Kiva. After the case was closed, Ryotaro and the Den-Liner crew keep the Den-Liner Police going just for kicks.
Liner Samuel's QuestsEdit
Before Liner and SingularEdit
Before start, Samuel ability to gain his data form to possess Ryotaro as a child to relies that power of human and anime beings was legend according to Computer. As possessed Ryotaro went to Zexal World from the past, he met a young Droite before Wanisaku appears. After protecting Droite by transformed Ryotaro and destroys Wanisaku, he asked to date for a year.
After Boukenger, the placed has changed that before possessing him. That sudden the attacked by still alive Wanisaku which is destroyed during in Singular. The strange Ryotaro saved Samuel from Wanisaku, that first thing was explaination with him cause Kai is Shadow's former creation to destroy his girlfriend Droite's memories, so she didn't know about him. Protecting Droite is his job, Ryotaro made Samuel to the Linebrace to destroy Wanisaku for good. After five Imagin Cards was perfectly tamed, sadly, Samuel and Ryotaro fails the mission, killing his TategaBike and Kai finally wiping Droite's memories. Having the failure to protect Droite's memories, Samuel angered and loss his point that Kai destroy her memory and kill TategaBike. Fortunately for call Ryotaro and Droite as a new family, her memories was restored which that he remembering anything inculding Eureka. Samuel newly gained the new power of Droite's crest and get a new bike called TatekoBike an TategaBike's sister. Ryotaro thanks him with Droite's restored memories to unlock his powers.
- There is a possibility that Ryotaro has retired as Kamen Rider Den-O after the last Climax movie (Den-O Trinity), since he is never seen again after that moment. After that, only the Tarōs (particulary Momotaros) that use the power.
- Ryotaro is tied with Gentaro Kisaragi as the youngest main protagonist Kamen Rider to date, not counting times when he has been forced into a child's body.