|This article is about a/an alternate reality/A.R. World (another rider's world) in Kamen Rider Decade.|
The World of Faiz (ファイズの世界 Faizu no Sekai) is the alternate reality where a version of Kamen Rider 555 takes place. In this world, students of the Smart Brain High School (スマートブレイン･ハイスクール Smāto Burēn Hai Sukūru) are being attacked nightly by monsters known as the Orphnoch. The backdrop used to enter the World of Faiz is a splitscreen featuring the Autovajin in Battle Mode and blue butterflies, referencing Smart Lady, a character from the original series who was Smart Brain Corporation's mascot of sorts. Within this A.R. World, Tsukasa assumes the role of a Smart Brain High student and is able to surpass the talent and intelligence of all of Lucky Clover, such as skills in tennis. Daiki's treasure in this world is the Faiz Belt, but eventually he relents and takes the unused Orga Belt instead.
Upon arriving in the World of Faiz and once more encountering the mysterious Daiki Kaito, Tsukasa found himself in a school uniform and enrolled at Smart Brain High School. He learns that the high school was attacked on a nightly basis by beings called the Orphnoch, with only Faiz to protect the school. Daiki challenged Tsukasa to find out who Faiz was, and Tsukasa then challenged the Lucky Clover clique to a tennis match to see if any of them were Faiz. He beat them, learning that they were Orphnoch who were also after Faiz, and was forced to become Decade, using Blade's power against them. However, Decade was outclassed when Momose appears as the Tiger Orphnoch and warned him to back off. Daiki then confronted the group, giving them a hint as to who Faiz was before going off. Then, the Lucky Clover members targeted Yuri Tomoda and Takumi Ogami, believing Yuri was Faiz until Takumi transformed and fought them off. When Tsukasa learned that Yuri was the target, he gone off to fight the Orphnoch, watching Faiz get defeated and losing the belt. The fight was then interrupted by Daiki Kaito who transformed into Kamen Rider Diend while revealing he used the Lucky Clover to take the belt for himself. Once the Centipede Orphnoch was destroyed, Decade and Diend had a stand off over the Faiz Belt as Momose attacked Yuri as the Tiger Orphnoch only to meet his match with Takumi who transformed into the Wolf Orphnoch to protect his friend.
After Tsukasa recovered the Faiz Gear, he learned Diend's reasons for wanting the belt before Takumi regained it so he and a shocked Yuri could escape on the Autovajin. However, as he exposed himself as the Wolf Orphnoch to protect her only to be forsaken, a saddened Takumi attempted to dispose of the Faiz Gear into the river. Managing to save the Gear while following him, Tsukasa returned to the photo studio where he put Yuri's confusion at ease. The next day, Daiki attacked Takumi to get the belt from him, nearly killing him when Tsukasa arrived with it. Refusing to take Tsukasa's words of something more precious than the Faiz Gear seriously, Daiki took Decade's Ride Booker, and Narutaki takes advantage of the situation as he takes Tsukasa into another dimension to be killed by Kamen Rider Ryuga. However, after interrogating Kiva-la on the whereabouts, Daiki intervened while claiming it was to get the Faiz Gear as he gave Tsukasa back the Ride Booker. While this occurred, the remaining Lucky Clover members started taking over the school to sire more of their kind until Takumi arrived to fight them in Orphnoch form. Though no match, Takumi attempted to protect Yuri's camera until Tsukasa arrived as he regained Faiz's Ride Cards. Decade and the Wolf Orphnoch were outmatched until Daiki arrived with the Faiz Gear and gave it to Takumi. The two transform and destroyed the Dragon and Lobster Orphnoch. However, the Tiger Orphnoch revived his followers, and Decade countered with the Final Attack Ride Faiz Blaster, destroying him and his followers in one shot. As Takumi and Yuri rekindled their friendship, Daiki stole the Orga Belt from the ruins of the school, and Tsukasa followed him to the World of Agito.
While Takumi does not appear to help in reviving Tsukasa in Kamen Rider × Kamen Rider W & Decade: Movie War 2010 he still appears to help him battle Super Shocker, assuming Blaster Form with the help of Decade's K-Touch and later uses the Jet Sliger to fight the Super Crisis Fortress.
- Takumi Ogami
- Yuri Tomoda
- Tiger Orphnoch
In the novel reimagination of the Kamen Rider Decade TV series, Kamen Rider Decade: The World of Tsukasa Kadoya ~The Garden Inside the Lens~, the World of Faiz is, as one of the Nine Worlds, not an alternate reality like in the TV series but the original world. The World of Faiz is one of the six worlds the Hikari Studio group, Tsukasa/Decade, Kaito/Diend, and Natsumi, have already traveled to by the start of the novel as they head for the three remaining worlds, and thus not much is seen about it.
- The World of Faiz is one of only two of the Nine Worlds, the other being the World of Kuuga, shown to have only one Rider. However while there was only one Rider in the original Kamen Rider Kuuga, Kamen Rider 555 and its movie featured multiple Riders: Kaixa, Delta, Psyga, Orga, and the Riotroopers. These Riders do not appear in the World of Faiz, though the other drivers were shown to exist and unused, with the taken by Diend (a Kamen Rider Orga appeared in Decade, but as one of the Dark Riders in the World of Negatives).