is a Japanese tokusatsu series that serves as the 13th installment in the Kamen Rider franchise and the fourth entry in the Heisei era. The series follows loner, Takumi Inui, and Yuji Kiba, who died and became a monstrous Orphnoch, and their newfound friends as they become involved in a conflict between Smart Brain, Inc., a group of Orphnoch who seek to exterminate humanity, and alumni of the Ryusei School, who were charged with stopping the corporation with technology they are unable to use.
Main characters Takumi Inui is a mysterious loner who became the after being hit by a car when he was a child. He attempted to use his newfound powers to protect people, but his failure to save the Ryusei School reunion from Kitazaki and an implanted memory that made him believe he was the culprit, forcing Takumi to isolate himself from others out of fear of betraying them and forget that he became an Orphnoch. By chance, he encounters Mari Sonoda and follows her under the belief that the she was carrying in a case was stolen from her days earlier. As a result, he reluctantly becomes involved in her crusade to fight the Orphnochs as Kamen Rider Faiz. Amidst conflicts with Masato Kusaka and Yuji Kiba, Takumi accepts his role as Faiz and joins the latter in protecting humans. Eventually, Takumi remembers his true nature as an Orphnoch and learns the truth behind the Ryusei School massacre before settling his rivalry with Yuji while defeating the Arch Orphnoch together.
As the Wolf Orphnoch, Takumi possesses increased power compared to most original and/or sired Orphnochs as well as superhuman speed and agility.
Utilizing the in conjunction with the belt, Takumi can transform into Kamen Rider Faiz. While transformed, he carries a variety of gadgets from the Faiz Gear that can be reconfigured into varying forms, such as the that changes from to and the that changes from to . His personal vehicle is the motorcycle, which stores the sword as a handlebar and can transform into a humanoid support robot to aid him in battle. His finishers are the via the Faiz Pointer, the via the Faiz Shot, and the via the Faiz Edge.
Later in the series, Takumi acquires advanced gadgets from the Faiz Gear that allow him to assume the following power-up forms: : Takumi's super form accessed from the stopwatch-like bracelet that grants the use of the ability, which has a 10 second time limit. He can also perform enhanced versions of his original Exceed Charges with the appropriate gadgets. : Takumi's final form accessed from the Faiz Phone in conjunction with the , which doubles as the Auto Vajin's trunk, that equips him with the jet pack, whose thrusters double as the twin shoulder-mounted . He can also reconfigure the Faiz Blaster from its briefcase-like to either its shotgun-like , which allows him to perform the Exceed Charge, or its sword-like , which allows him to perform the and Exceed Charges.
During the events of the V-Cinema Kamen Rider 555 20th: Paradise Regained, Takumi utilizes the in conjunction with the belt to transform into , which has access to Axel Form.
Takumi Inui is portrayed by .
Mari Sonoda is a member of the Ryusei School who strives to see the good in others and dreams of becoming a beautician. Though she was sent the Faiz Gear and Auto Vajin by their foster father, Hanagata, she was unable to use them. After seeing Takumi Inui successfully use the equipment, she insists he accompany her in fighting the Orphnochs.
In an alternate timeline depicted in the film Kamen Rider 555: Paradise Lost, Sonoda serves as the leader of the , a guerilla force of anti-Orphnoch resistance fighters and the last known bastion of human resistance in an Orphnoch-dominated world.
During the events of the V-Cinema Kamen Rider 555 20th: Paradise Regained, Mari becomes the due to the activation of her implanted Orphnoch DNA by Smart Brain.
Mari Sonoda is portrayed by . As a child, Mari is portrayed by .
Yuji Kiba is a friendly and polite young man who became the after dying in a car crash and ending up in a comatose state for two years. Upon awakening, Yuji discovers his uncle sold his family's company and his girlfriend Chie Morishita left him for his cousin Kazuaki Kiba. After murdering Kazuaki and Morishita in anger, Yuji turns to Smart Brain for protection, only to learn of their tactics and resolve to fight them and protect humans using his Orphnoch powers. In pursuit of this goal, he befriends Yuka Osada and Naoya Kaido, but forms a rivalry with Takumi Inui due to a misunderstanding until they learn each other's true identities and intentions. Upon learning of Yuka's death, who he believed was killed by the police, Yuji kills Masato Kusaka for the Kaixa Gear, discards his ideals, and eventually replaces Kyoji Murakami as the chairman of Smart Brain. However, Yuji's humanity is restored following a final battle with Takumi and he later sacrifices himself to help him defeat the Arch Orphnoch.
In an alternate timeline depicted in the film Kamen Rider 555: Paradise Lost, Yuji maintained his desire to protect humans from other Orphnochs until Osada and Naoya are killed by the Elasmotherium Orphnoch and Yuji is manipulated by Smart Brain into believing humanity had betrayed him. Accepting the , one of two "perfect" Rider Gears created by Smart Brain that can only be used by Orphnochs, he agrees to serve them as and fights Takumi, who eventually defeats Yuji and shows him the error of his ways. Yuji subsequently sacrifices himself to weaken the Elasmotherium Orphnoch so Takumi can kill it.
As the Horse Orphnoch, Yuji wields a sword and shield, and can assume an alternate centaur-themed . In the series finale and Paradise Lost, he evolves his Horse Orphnoch form into where he gains increased power.
Utilizing the in conjunction with the belt, Yuji can transform into Kamen Rider Orga. While transformed, he wields the , which can switch between and . He can also use the Orga Stlanzer to perform the Exceed Charge.
Yuji Kiba was portrayed by .
Masato Kusaka is a student of the Ryusei School and childhood friend of Mari Sonoda, having fallen in love with her after she saved him from bullies, and failed to attend the Ryusei School reunion. After learning of the massacre, he vowed to destroy the Orphnochs with extreme prejudice and wipe his hands of the blood he essentially spilled that night. To this end, he acquired the , which can only be used by Orphnochs or humans implanted with a sufficient amount of Orphnoch DNA, and became , using his implanted Orphnoch DNA to survive the belt's fatal side effects longer than its past human users and developing a rivalry with Takumi Inui. Eventually, Masato begins to suffer from the Kaixa Gear's side effects before he is killed by Yuji Kiba.
In an alternate timeline depicted in the film Kamen Rider 555: Paradise Lost, Masato is killed by Kamen Rider Psyga.
During the events of the V-Cinema Kamen Rider 555 20th: Paradise Regained, an android modeled after Masato and programmed to kill alumni of the Ryusei School who became Orphnochs is sent by Smart Brain, only to be destroyed by Takumi Inui as Kamen Rider Faiz. A second android Masato takes the android Kitazaki's place after the latter's destruction.
Utilizing the in conjunction with the belt, Masato can transform into Kamen Rider Kaixa. While transformed, he carries a variety of gadgets from the Kaixa Gear that can be reconfigured into varying forms, such as the that similar to the Faiz Pointer changes from to Kick Mode and the that like the Faiz Shot changes from Multi Digital Camera Mode to Knuckle Mode. He also wields the , which can switch between and . His personal vehicle is the motorcycle/sidecar, which can transform into a walker-esque support robot to aid him in battle. His Exceed Charges are the via the Kaixa Pointer, the Grand Impact via the Kaixa Shot, and the via the Kaixa Blaygun.
In Paradise Regained, the android Masato utilizes the in conjunction with the Kaixa Driver to transform into , which like Next Faiz has access to Axel Form. While transformed, he dual wields the twin bladed tonfa.
Masato Kusaka is portrayed by .
Recurring characters Orphnochs are humans reborn as grey animal or plant-themed zombie-like monsters who were meant to be the next stage in human evolution. Two types seen throughout the series are "original" Orphnochs, dead humans who are subsequently resurrected as monsters, and "sired" Orphnochs, humans who survive being attacked by an Orphnoch similarly to vampires and werewolves, though they are weaker than originals. While both types are capable of switching between their human and Orphnoch forms, they suffer from a genetic flaw that causes them to eventually and inevitably disintegrate due to the human body being unable to withstand such a rapid evolution, with the use of Rider Gears accelerating the process. Additionally, there exists a third type called "evolved" Orphnochs, who are genetically perfect and significantly more powerful, but lack the ability to turn back into their human forms and can only reach this stage with assistance from the Arch Orphnoch.
All Orphnochs share superhuman abilities and senses as well as the ability to produce tendrils capable of killing humans or converting them into more Orphnochs. Furthermore, they are capable of withstanding conventional firearms, with some capable of withstanding attacks by Rider Gear users.
In an alternate timeline depicted in the film Kamen Rider 555: Paradise Lost, Orphnochs were able to retain the use of their human forms while adapting away the genetic flaw that shortened their life spans after overthrowing humanity as the dominant species on Earth.
Yuka Osada is a teenage girl who was bullied by her younger sister, who their parents favored over her, and other girls from her school and basketball team. The emotional stress from this leads to her falling down snow-covered stairs, reviving as the , and slaughtering her sister and the basketball team. Following this, she meets Yuji Kiba and joins him in protecting humans, though she occasionally and secretly kills people she deems "bad guys". Throughout the series, she exchanges texts with Keitaro Kikuchi, eventually developing a semi-romantic relationship with him along the way, and developed a crush on Naoya Kaido, though he does not reciprocate. Near the end of the series, she is mortally wounded by the Bat Orphnoch and killed by Saeko Kageyama.
In an alternate timeline depicted in the film Kamen Rider 555: Paradise Lost, Osada joins Yuji and Kaido in proving to the Human Liberation Army that they were on their side. However, the trio fall into a Smart Brain trap, during which Osada and Kaido are killed by the Elasmotherium Orphnoch.
As the Crane Orphnoch, Osada can fly at incredible speeds, create afterimages, and possesses increased lung capacity and superhuman hearing and jumping. Additionally, her film counterpart can assume an alternate , gaining larger bird wings on her collar and sides as well as crane-like legs.
Yuka Osada is portrayed by .
Naoya Kaido is an overly eccentric young man prone to incredibly fast speeches and constant mood swings who Eiichi Toda, the temporary chief of Smart Brain, sired as the to show Yuji Kiba and Yuka Osada how Orphnochs must make allies. In his younger years, Kaido played the guitar, but was sabotaged by his teacher, who destroyed his motor skills in his left hand, forcing him to abandon music. After struggling with his nature as an Orphnoch, Kaido lives with Yuji and Osada despite not sharing their desire to protect humans. Throughout the series, Kaido sides with Smart Brain, becoming Kamen Rider Faiz on one occasion and commander of their Riotroopers on a separate occasion, but his conscience ultimately stops him from committing heinous acts at the last second. Following Osada and Yuji's deaths, Kaido reintegrates into human society.