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 believed he was the culprit forced Takumi to isolate himself from others out of fear of betraying them and forget that he became an Orphnoch.
While transformed, he can perform Exceed Charge (エクシードチャージ, Ekushīdo Chāji) finishers and wields a variety of gadgets from the Faiz Gear, such as the SB-555L Faiz Pointer (SB-555L ファイズポインター, SB-555L Faizu Pointā) flashlight that he can use in Kick Mode (キックモード, Kikku Mōdo) to perform the (Axel) Crimson Smash ((アクセル) クリムゾンスマッシュ, (Akuseru) Kurimuzon Sumasshu) Exceed Charge, the SB-555C Faiz Shot (SB-555C ファイズショット, SB-555C Faizu Shotto) digital camera that he can use in Knuckle Mode (ナックルモード, Nakkuru Mōdo) to perform the (Axel) Grand Impact ((アクセル) グランインパクト, (Akuseru) Guran Inpakuto) Exceed Charge, and the SB-555H Faiz Edge (SB-555H ファイズエッジ, SB-555H Faizu Ejji) sword that he can use to perform the (Axel) Sparkle Cut ((アクセル) スパークルカット, (Akuseru) Supākuru Katto) Exceed Charge.
The SB-555H Faiz Edge also doubles as a handlebar for his personal vehicle, the SB-555V Auto Vajin (SB-555V オートバジン, SB-555V Ōto Bajin) motorcycle, which can transform into a support robot to aid him in combat.
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.
In the series finale and Paradise Lost, Yuji evolves into the Horse Orphnoch's Raging Mode (激情態, Gekijō-tai), gaining increased power.
The emotional stress from this leads to her falling down snow-covered stairs, reviving as the Crane Orphnoch (クレインオルフェノク, Kurein Orufenoku), and slaughtering her sister and the basketball team.
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.
As the Crane Orphnoch, Osada can fly at incredible speeds, create afterimages, and possesses increased jumping capabilities and lung capacity, and superhuman hearing.
Additionally, her film counterpart can assume a Flying Mode (飛翔態, Hishō-tai), gaining larger wings on her collar and sides as well as crane-like legs.
Naoya Kaido (海堂 直也, Kaidō Naoya) 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 Snake Orphnoch (スネークオルフェノク, Sunēku Orufenoku) 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.
In an alternate timeline depicted in the film Kamen Rider 555: Paradise Lost, Kaido joins Yuji and Osada in proving to the Human Liberation Army that they were on their side, only to fall into a Smart Brain trap and come under attack by the Elasmotherium Orphnoch.
During the events of the V-Cinema Kamen Rider 555 20th: Paradise Regained, Kaido runs a ramen restaurant and looks after young Orphnochs, such as Hisao, Kouta, and Kei.
In an alternate timeline depicted in the film Kamen Rider 555: Paradise Lost, Smart Brain has become the world's ruling government following the Orphnochs' takeover of Earth.
The first iteration of Smart Lady is portrayed by Hitomi Kurihara (栗原 瞳, Kurihara Hitomi) in the series and the film Kamen Rider 555: Paradise Lost, and the second iteration of Smart Lady is portrayed by Amane Shindō (進藤 あまね, Shindō Amane) in the V-Cinema Kamen Rider 555 20th: Paradise Regained.
As the Centipede Orphnoch, Takuma possesses superhuman strength and speed, a body covered in toxic extendable spikes, the ability to fire blue energy rays, 180 degree vision, and the use of a spiky centipede-like whip.
Enjoying seeing her victims suffer and comforting them in disturbing ways, she has a habit of sending them a bottle of rare wine as their final drink.
As the Lobster Orphnoch, Kageyama possesses flexible armor, the ability to fire blue energy balls from her hands, a pair of gauntlets capable of withstanding most forms of attack, and the use of a rapier.
Not long after joining, he develops a habit of folding animal-themed origami and lighting them on fire before initiating a massacre while listening to rap music, with the flame usually dying out once he kills the last person present.
Prior to the series' beginning, they attended a reunion, where all of the alumni present were either killed or sired as Orphnoch, with only Masato Kusaka retaining his memories of the attack since he was not there.
Hanagata (花形) is the founder and former chief of Smart Brain who can transform into the Goat Orphnoch (ゴートオルフェノク, Gōto Orufenoku) and sought to evolve mankind for the better.
However, he discovered he was dying due to his Orphnoch nature, realized the error of his ways, and disappeared, taking the Rider Gears with him in the hopes of stopping humanity from becoming monsters.
He would go on to become the Ryusei School's foster father and secretly give them the Rider Gears, believing they would be able to stop the other Orphnochs, and watched over them from the shadows for years.
In the present, Hanagata resurfaces to aid Takumi Inui and Masato Kusaka by giving them new equipment before stripping Smart Brain's current chief, Kyoji Murakami, of his duties and appointing Yuji Kiba as the permanent head of the company in response to the Arch Orphnoch's eventual awakening.
While attempting to see his students, Mari Sonoda and Rina Abe, one more time, he is stopped by Masato, who learned of Hanagata's true nature as an Orphnoch.
Abe temporarily takes up the mantle of Kamen Rider Delta and overcomes the side effect, but her lack of combat prowess forces her to give it to her friend Shuji Mihara, who initially refuses.
After helping Takumi Inui and Yuji Kiba defeat the Arch Orphnoch, Shuji joins Abe in running the Sousai Children's Home.
He leads the Orphnochs in their crusade to exterminate humanity under the personal supervision of Kyoji Murakami until he is killed in battle by Takumi Inui as Kamen Rider Faiz.
While transformed, he is equipped with the SB-315F Flying Attacker (SB-315F フライングアタッカー, SB-315F Furaingu Atakkā) jetpack, which can convert into Booster Rifle Mode (ブースターライフルモード, Būsutā Raifuru Mōdo).
Additionally, the joysticks can separate into Tonfa Edge Mode (トンファーエッジモード, Tonfā Ejji Mōdo), which allow him to perform the Psyga Slash (サイガスラッシュ, Saiga Surasshu) Exceed Charge.