The story takes place in a world plagued by Shocker, a mysterious terrorist organization. To further its plans for world domination, Shocker recruited its agents through kidnapping, turning their victims into mutant cyborgs and, ultimately, brainwashing them. However, one victim named Takeshi Hongo escaped just before the final brainwashing. With his sanity and moral conscience intact, Hongo battled Shocker’s minions as the grasshopper-themed altered human superhero Kamen Rider 1. Another of Shocker’s victims, freelance photographer Hayato Ichimonji, had also been given cyborg implants, but was saved by Kamen Rider from the brainwashing process to become Kamen Rider #2. Assisted by motorcycle race team manager Tobei Tachibana and FBI agent Kazuya Taki, the Kamen Riders fought in both solo and partnered missions against both Shocker and its successor organization Gel-Shocker.

One night, Shiro Kazami accidentally witnesses a murder by the evil organization Destron, making him their next target. In their first attempt, they planted a bomb pebble into his coffee, but the attempt was foiled when Shiro’s sister, Yukiko, surprised him, causing him to spill his coffee. In their second attempt, they attacked him while practicing motorcycle racing with Tobei Tachibana. In their third attempt, a Destron soldier, disguised as a doctor, tried to put a poison shot in Shiro, while he was being transported to the hospital (after Destron’s second attempt), but Shiro regains consciousness and kills the soldier. Meanwhile, a young woman named Junko Tama stumbled upon Destron’s base. Suddenly, she was attacked by Destron. While trying to escape, she ran into Shiro, who was heading home on his motorcycle, but Shiro didn’t see the Destron soldiers. Surprised, Junko fainted and Shiro took her home. While Junko was being taken care of by Shiro’s family, Shiro reported her story to the police. When he returned home, he found his family being murdered by the Hasami Jaguar, a jaguar monster with blades for hands. Hasami Jaguar then prepares to kill Junko and Shiro, but is stopped by Shiro’s high school teacher, Takeshi Hongo, who transformed into Kamen Rider 1. Shortly after he drove off the Destron forces, Kamen Rider 2 shows up, but too late. A vengeance-fueled Shiro asked the Riders to turn him into a cyborg, but the Riders refused, explaining to Shiro what would happen if he did get turned into a cyborg: he wouldn’t be able to live up to his family. Then the Riders asked Junko for the location of the Destron base she stumbled upon earlier. The next day, the Riders infiltrate the base, only to get caught in a trap. Shiro shows up and saves their lives, but gets injured in the process. The Riders had no choice but to turn Shiro into a cyborg. When the Riders were attacked, and almost killed, by Kame Bazooka, Shiro shows up as Kamen Rider V3. Now, Shiro uses his new power to protect mankind against Destron.

A plane crashes in the Amazon rainforest, leaving young Amazon (Daisuke Yamamoto) stranded without his parents. Soon adopted by an Incan tribe, Amazon becomes a wild child, living off the land. However, Amazon’s idyllic existence is cut short when Gorgos, the Ten Faced Demon, massacres his village, slaughtering everyone except himself in search for the powerful “GiGi Armlet”, which gives the bearer fantastic power. Elder Bago, last of the Incas, gives the GiGi Armlet to Amazon for safekeeping while using his knowledge of Incan science and magic to perform a mystical “operation” on Daisuke, transforming him into the powerful “Kamen Rider Amazon” before he died. Arriving at Japan, Amazon battles Geddon without full knowledge of their reason of pursuing him. Befriending the nephew and niece of Professor Kousaka, Amazon learns the nature of the GiGi Armlet as he defeats Geddon and then the Garanda Empire.

Shigeru Jo joins the evil organization Black Satan after the death of his close friend Goro Numata, who he considered his mentor. He, promised power, and fueled by a desire for revenge, undergoes surgery to become one of Black Satan’s super warriors. However, Shigeru knows that Black Satan were in fact the murderers of his friend; he was using Black Satan in order to gain new powers. The newly powered up Shigeru escapes from the Black Satan headquarters before they can brainwash him into following their campaign of evil and becomes Kamen Rider Stronger. While escaping from Black Satan, Stronger meets Yuriko Misaki another cyborg warrior created by Black Satan who has the ability to transform into Electro-Wave Human Tackle. Together they fight the evil Black Satan and later the Delza Army to restore peace in Japan.

After being kidnapped by the cult Gorgom on the night of their 19th birthday, stepbrothers Kohtaro Minami and Nobuhiko Akizuki were submitted to a cyborg surgery with the purpose of becoming the candidates for the next Gorgom Creation King. Both of them are called Century Kings and are destined to best each other in a final battle – whoever wins will become the next Creation King. Kohtaro escaped before getting brainwashed (which is the final step in the surgery), with help from his foster father, and turned against Gorgom. He soon finds out the horrific truth from his stepfather: Gorgom originally killed his true parents and, since both Kohtaro and Nobuhiko were born on the day of a solar eclipse, referred as “Black Sun” and “Shadow Moon”. Kohtaro, taking on the name of Kamen Rider Black, was determined to rescue his stepbrother from Gorgom while protecting Japan. However, later in the series, Nobuhiko emerged as Shadow Moon to fight Kohtaro with the survivor becoming the next Creation King.

After the downfall of Gorgom, Kohtaro Minami has gotten a job as a helicopter pilot in a business owned by the Sahara family, who have also taken him into their home. Kohtaro is later captured by the Crisis Empire and offered a place in their group. When Kohtaro refused, his King Stone was shattered and he was thrown into space where the sun’s radiation mutated his King Stone and he mutated into Kamen Rider BLACK RX. With his new powers, he battles the Crisis Empire and thwarts their plans to take over Earth.

Monsters called the Gurongi appear in modern day Tokyo and begin murdering people, as part of an event they seem to call “Gegeru”. Yusuke Godai, an archaeologist, uses the Arcle belt to transform into Kamen Rider Kuuga, as a member of a tribe of humans did thousands of years ago, to stop the Gurongi’s “Gegeru”, a vicious game to decide which of their kind will become their new leader.

Shinji Kido, an intern at a local newspaper, investigates the disappearances of people throughout the city and finds an Advent Card deck at an apartment where every reflective surface has been covered up. He then discovers the terrifying truth that people have been abducted into a Mirror World by monsters to be eaten. This also drags him into the Rider War, a fight between twelve other holders of Advent Decks to be granted a single wish once all of the other competitors have been killed. Shinji uses his deck to make a contract with the monster Dragreder, becoming Kamen Rider Ryuki to find a way to protect people from the Mirror World monsters, and to find a way to stop the Rider War from taking other lives.

Ryotaro Nogami, a young man who is seemingly the unluckiest man in the world, happens upon a strange train pass on the ground, and when he happens to enter a building at 11:11:11, he finds himself in a massive barren desert with a massive train as the only thing within. He then meets Hana, the Rider Pass’ original owner, who identifies him as a Singularity Point, a person immune to the effects of changes to the past. He has also unluckily become the host of Momotaros, a monster known as an Imagin who is one of several who have come back in time to this point in history to trick people into granting them their “wishes” so they may go further back in time to that person’s past to alter the future to ensure that the Imagin’s future is the one that will happen. Ryotaro’s unique status as a Singularity Point makes it so he is immune to Imagin powers, except they still possess him and act through his body, as without granting a wish they have no physical form. Together, Ryotaro and Momotaros (and later other Imagin) fight as Kamen Rider Den-O to help Ryotaro preserve the flow of time.

Futo, the Windy City, is threatened by monsters known as Dopants who are people who have gained a drug-like addiction to mysterious devices known as Gaia Memories. Private investigator Shotaro Hidari and his mysterious research companion Philip often find themselves investigating Dopant-related crimes and fuse together by means of the Double Driver and their own Gaia Memories to fight the monsters as Kamen Rider Double. Their investigation leads them to fight against the Sonozaki family who are the heads of the Gaia Memory drug smuggling ring, and themselves Dopants.

Emu Hojo is a doctor doing his residency in a hospital specializing in treating victims of the Bugster virus, a computer virus that managed to jump to humans during the Y2K threat that turns its victims into monstrous Bugsters whose essences are held in video game cartridges known as Gashats. In order to stop a Bugster, doctors undergo a surgery to gain antibodies against their infection and use a device known as a Gamer Driver to use Gashats to transform into Kamen Riders. Emu, who in his teenage years was the professional gamer “M”, obtains a Gamer Driver, and despite never having undergone the surgery to use it, transforms into Kamen Rider Ex-Aid to end the Bugster Virus menace as part of his desire to become a “Super Doctor” who will save the world, using his knowledge of video games to best the Bugsters.

Ten years ago on an expedition to Mars, an artifact known as Pandora Box was discovered. Upon its return to Earth in Japan, it was activated by someone there and caused the country to split up into three rival nations and also caused the emergence of monsters known as Smash, created from humans affected by the Nebula Gas created by the walls. The physicist Sento Kiryu is contracted by the government of Touto, the eastern region of Japan, to decipher the mystery behind Pandora Box and the Smash, which he does by transforming into Kamen Rider Build through the use of the Build Driver and Fullbottles, which contain a purified Nebula Gas created from defeated Smashes.

Sougo Tokiwa, a high school senior who wants to one day be a “king”, happens upon a mysterious clock-like Ridewatch on his bike one day. Soon after, he is approached by a woman named Tsukyomi who says that she has come from the future year 2068 where Sougo has apparently become the tyrannical ruler known as Oma Zi-O who uses the powers of all Kamen Riders to oppress humanity. She has come back in time to see if Sougo is actually the man she thinks he is, but his selflessness convinces her otherwise, despite her fellow Resistance fighter Geiz’s doubts that Sougo is indeed their future enemy. In an incident that leaves Sougo trapped in the year 2017 where he meets Sento Kiryu, he comes across the Time Jackers, members of another resistance cell in 2068 who have come back in time to kill Sento so their own chosen leader will become a tyrant, and Woz, one of Oma Zi-O’s closest supporters who gives Sougo the Ziku-Driver belt which he uses to transform into Kamen Rider Zi-O in order to fight the Another Riders created by the Time Jackers to kill him and change the past by eliminating the powers of the current Kamen Rider whose powers they copy. Sougo, Tsukuyomi, and Geiz who also can become a Kamen Rider work together travelling through time to prevent the Time Jackers from installing their own tyrannical king while keeping an eye on Sougo, whose ability to obtain other Kamen Riders’ powers through other Ridewatches is eerily similar to the evil Oma Zi-O they fear he may become.