List of Kamen Rider W characters

Kamen Rider Double (仮面ライダーW (ダブル), Kamen Raidā Daburu) is a Kamen Rider transformed by both Shotaro Hidari and Philip through the Double Driver (ダブルドライバー, Daburu Doraibā) belts and their own set of purified USB memory-like Gaia Memories (ガイアメモリ, Gaia Memori). The Double Drivers linked, they are used to transfer Philip's consciousness into Shotaro along with the former's inserted Gaia Memory. Their catchphrase at the start of a battle is "Now, count your sins!" (さあ、お前の罪を数えろ！, Saa, omae no tsumi o kazoero!), which is originally used by Sokichi Narumi. Double's ability to function is dependent on the condition of both Shotaro and Philip, as any disruption physical or mental could affect the Kamen Rider's mobility or cancel the transformation entirely. Double rides the modified Honda CBR1000RR motorcycle called the HardBoilder (ハードボイルダー, Hādo Boirudā), using the Rotation-Interchange Base RevolGarry (回転換装ベースリボルギャリー, Kaiten Kansō Bēsu Riborugyarī) mobile garage to covert it into the HardTurbuler (ハードタービュラー, Hādo Tābyurā) hovercraft or the HardSplasher (ハードスプラッシャー, Hādo Supurasshā) personal water craft.

Normally, Double uses different combinations of Gaia Memories to access various combinations of powers, weapons, strengths, and weaknesses through Half Changes (ハーフチェンジ, Hāfu Chenji), switching from one form to another by switching out one or both Gaia Memories in the belt in a Memory Change (メモリチェンジ, Memori Chenji). Each Half Change uses a Maximum Drive (マキシマムドライブ, Makishimamu Doraibu) finisher, which is designed to destroy a Dopany's Gaia Memory via Memory Break (メモリブレイク, Memori Bureiku).

• CycloneJoker (サイクロンジョーカー, Saikuron Jōkā): Double's default form using the Cyclone and Joker Memories, the most well-balanced of Double's usual form with his wind-powered kicks having increased damage and cutting potential. This form's Maximum Drive finisher is a Rider Kick called the Joker Extreme (ジョーカーエクストリーム, Jōkā Ekustorīmu), during which a tiny controlled tornado lifts Double into the air before the Kamen Rider's body splits down the middle as the halves reach their target in a drop kick fashion before reconnecting.
  • CycloneMetal (サイクロンメタル, Saikuron Metaru): A Half Change accessed through the Cyclone and Metal Memories, using the Metal Shaft to creates blades of wind. This form's Maximum Drive finisher is the Metal Twister (メタルツイスター, Metaru Tsuisutā) where Kamen Rider Double spins around while swinging the Metal Shaft covered in an aura of wind.
  • CycloneTrigger (サイクロントリガー, Saikuron Torigā): A Half Change accessed through the Cyclone and Trigger Memories, using the Trigger Magnum to shoot out highly compressed air. This form's Maximum Drive finisher is the Trigger Aerobuster (トリガーエアロバスター, Torigā Earobasutā), firing multiple shots of pressurized air at the enemy.
• HeatMetal (ヒートメタル, Hīto Metaru): Double's form using the Heat and Metal Memories, considered the strongest, yet slowest of the 9 forms while imbuing the Metal Shaft with fire to increase its destructive abilities. This form's Maximum Drive finisher is the Metal Branding (メタルブランディング, Metaru Burandingu), causing one or both ends of the Metal Shaft to ignite on fire and deliver a final blow to the opponent. First used in Kamen Rider Decade: All Riders vs. Dai-Shocker.
  • HeatJoker (ヒートジョーカー, Hīto Jōkā): A Half Change form accessed through the Heat and Joker Memories, enabling Double to throw flaming punches. This form's Maximum Drive finisher is a Rider Punch called the Joker Grenade (ジョーカーグレネード, Jōkā Gurenēdo), during which Kamen Rider Double somersaults in mid-air, then HeatJoker's body splits down the middle during descent as the halves each hit the target with elementally energized hooks. First used in Kamen Rider Decade: All Riders vs. Dai-Shocker.
  • HeatTrigger (ヒートトリガー, Hīto Torigā): A Half Change accessed through the Heat and Trigger Memories, using the Trigger Magnum to shoot blasts of fire. This form's Maximum Drive finisher is the Trigger Explosion (トリガーエクスプロージョン, Torigā Ekusupurōjon), which fires a single constant stream of fire that completely vaporizes the enemy. HeatTrigger is the only form of Kamen Rider Double's that has attempted to perform a Twin Maximum, in which the Trigger Magnum blasts out a massive fireball that incinerates anything in its path.
• LunaTrigger (ルナトリガー, Runa Torigā): A form accessed through the Luna and Trigger Memories, effective in long range using the Trigger Magnum to fire curving gold and blue energy bolts that home on their intended target. This form's Maximum Drive finisher is the Trigger Full Burst (トリガーフルバースト, Torigā Furu Bāsuto), which fires multiple charged homing shots at the enemy.
  • LunaJoker (ルナジョーカー, Runa Jōkā): A Half Change accessed through the Luna and Joker Memories, enabling Double to stretch his right limbs to extend his strike range. This form's Maximum Drive finisher is a Rider Chop called the Joker Strange (ジョーカーストレンジ, Jōkā Sutorenji), during which LunaJoker splits down the middle, the Luna half makes four copies of itself, and all five Luna halves execute rapid-fire karate chops on the target, and then the Joker half strikes the target with an energy powered chop.
  • LunaMetal (ルナメタル, Runa Metaru): A Half Change accessed through the Luna and Metal Memories, enabling the Metal Shaft's range to be extended to the point of the weapon being used like whip. This form's Maximum Drive finisher is the Metal Illusion (メタルイリュージョン, Metaru Iryūjon) where Kamen Rider Double spins the Metal Shaft around to create golden rings that float around Kamen Rider Double, before unleashing them upon the target all at once.

Double also uses Memory Gadgets (メモリガジェット, Memori Gajetto) are items powered by artificial Gaia Memories called Giji Memories (ギジメモリ, Giji Memori, "Pseudo Memories") that change from Gadget Mode (ガジェットモード, Gajetto Mōdo) to Live Mode (ライブモード, Raibu Mōdo) to give Double's weapon's a boost with the use of a Soul Memory activating a Maximum Drive.

• The Stag Phone (スタッグフォン, Sutaggu Fon) are two cellular phones Shotaro and Philip own which switch between Cell Phone Mode (携帯モード, Keitai Mōdo) and Stag Mode (スタッグモード, Sutaggu Mōdo) with the use of the Stag Memory (スタッグメモリ, Sutaggu Memori). Double uses a Stag Phone to normally summon and control the HardBoilder and the RevolGarry, but attaches it to Trigger Magnum to execute a Trigger Stag Burst (トリガースタッグバースト, Torigā Sutaggu Bāsuto) Maximum Drive or with the Metal Shaft to perform the Metal Stag Break (メタルスタッグブレイク, Metaru Sutaggu Bureiku) Maximum Drive.
• The Spider Shock (スパイダーショック, Supaidā Shokku) is a G-Shock wrist watch that switches between Wrist Watch Mode (腕時計モード, Udedokei Mōdo) and Spider Mode (スパイダーモード, Supaidā Mōdo) with the use of the Spider Memory (スパイダーメモリ, Supaidā Memori). It has a grappling hook in Wrist Watch Mode. It can also shoot out trackers which can be tracked in Wrist Watch Mode. When attached to the Trigger Magnum, it allows Kamen Rider Double to fire out a net that can capture Dopants. When attached to the Metal Shaft, it allows Kamen Rider Double to shoot out a webbed string that restrains a Dopant
• The Bat Shot (バットショット, Batto Shotto) is a digital camera that switches between Digicam Mode (デジカメモード, Dejikame Mōdo) and Bat Mode (バットモード, Batto Mōdo) with the use of the Bat Memory (バットメモリ, Batto Memori). A live video feed can be linked to the Stag Phone while in Bat Mode. Its flash can disorient others, and when attached to the Metal Shaft (a combination that Shotaro dubs the Sonic Shaft (ソニックシャフト, Sonikku Shafuto)), it can emit sonic waves strong enough to shatter solid objects. The Bat Shot also has a Maximum Drive for the Luna Memory, allowing its flashes to reveal and stun any hidden targets in its vicinity. When attached to the Trigger Magnum, it allows Kamen Rider Double to perform the Trigger Bat Shooting (トリガーバットシューティング, Torigā Batto Shūtingu) Maximum Drive, locking onto the target through the Bat Shot and then firing a concentrated blast from the Trigger Magnum.
• The Frog Pod (フロッグポッド, Furoggu Poddo) is a speaker that switches between Speaker Mode (スピーカーモード, Supīkā Mōdo) and Frog Mode (フロッグモード, Furoggu Mōdo) with the use of the Frog Memory (フロッグメモリ, Furoggu Memori), which is similar to a MP3 Player that acts as a sound recorder. When the recording is played back, the Frog Pod can modulate the sound to be anyone's voice. Its primary uses are for audio recording and analysis. The Frog Memory and manual for building the Frog Pod are sent to Philip by what he assumed to be Shroud.
• The Denden Sensor (デンデンセンサー, Denden Sensā) is a pair of night vision goggles that switches between Goggle Mode (ゴーグルモード, Gōguru Mōdo, also translated as "Night Scope Mode") and Denden Mode (デンデンモード, Denden Mōdo) with the use of the Denden Memory (デンデンメモリ, Denden Memori). Its primary ability is to detect changes in the light spectra and alert its user to targets invisible to the naked eye. It is also used as a surveillance device, being able to store 8 terabytes of information in its Giji Memory. The Denden Sensor is the second Memory Gadget Philip is seen constructing from a set of instructions sent to him by Shroud.

The Xtreme Memory (エクストリームメモリ, Ekustorīmu Memori) is a special bird-like Gaia Memory that changes from Live Mode (ライブモード, Raibu Mōdo) to Memory Mode (メモリモード, Memori Mōdo) for Double to assume his ultimate form: CycloneJokerXtreme (サイクロンジョーカーエクストリーム, Saikuron Jōkā Ekusutorīmu). Being an evolved form of Double's CycloneJoker form, the Xtreme Memory contains a digitized Philip which causes him and Shotaro to fully integrate into a single being for the duration of the form with full access to the True Gaia Memory via the iridescent band going down the middle of the Kamen Rider's body called the Crystal Server (クリスタルサーバー, Kurisutaru Sābā). Double CycloneJokerXtreme uses the Prism Bicker (プリズムビッカー, Purizumu Bikkā) that splits into the Prism Sword (プリズムソード, Purizumu Sōdo), which neutralizes more Dopants' regenerative abilities, and Bicker Shield (ビッカーシールド, Bikkā Shīrudo) which uses the Prism (プリズム, Purizumu) Memory to link the power of four Maximum Drives into one. Double's Maximum Drives in this form are the Double Xtreme (ダブルエクストリーム, Daburu Ekusutorīmu) and Double Prism Xtreme (ダブルプリズムエクストリーム, Daburu Purizumu Ekusutorīmu) Rider Kicks, Prism Break (プリズムブレイク, Purizumu Bureiku) slash, Bicker Charge Break (ビッカーチャージブレイク, Bikkā Chāji Bureiku) sword and shield charged slash, and Bicker Finallusion (ビッカーファイナリュージョン, Bikkā Fainaryūjon) laser blast. Double can evolve the form further by assuming CycloneJokerGoldXtreme (サイクロンジョーカーゴールドエクストリーム, Saikuron Jōkā Gōrudo Ekusutorīmu) form being exposed to strong winds, like in Kamen Rider W Forever: A to Z/The Gaia Memories of Fate, with use of the Golden Xtreme (ゴールデンエクストリーム, Gōruden Ekusutorīmu) Rider Kick Maximum Drive.

Shotaro Hidari (左 翔太郎, Hidari Shōtarō) is the man on the streets, a self-proclaimed "hardboiled detective" who emulates famous pulp fiction private eyes characters while dressing himself in 1940s fashion with a sharp enough intuition to sometime figure out the culprit behind a crime before having Philip confirm his suspicions with evidence. Vowing to ensure that no one ever feels sad, Shotaro became a protégé of Futo's private investigator Sokichi Narumi after admiring his work as a child. Unlike his mentor, Shotaro was incapable of making the tough decisions most of the time due to his kindhearted nature, which is the main reason why many consider him "halfboiled".

Following Sokichi's death in the Begins Night (ビギンズナイト, Biginzu Naito) incident, their investigation leading to Shotaro meeting Philip, Shotaro promises to continue in his mentor's stead while becoming a man worthy of wearing Sokichi's white fedora. Thus Shotaro works to stop the Dopant crime wave in Futo by providing his body as Kamen Rider Double, taking pride in the role and being called a "Kamen Rider" by the citizens. While his body was not meant to handle Gaia Memories as he was never intended to be partnered with Philip, Shotaro adapted to the situation as he eventually become both worthy of being Double and wearing Sokichi's white fedora.

As Double, Shotaro possesses Gaia Memories called Body Memories (ボディメモリ, Bodi Memori) which form the left side of Double's body while determining the fighting style in conjunction with Philip's Soul Memories. They are also used in Double's Maximum Drive attacks.

• Joker (ジョーカー, Jōkā): The Joker Memory, also known as the Ace Memory (切り札の記憶, Kirifuda no Kioku), allows the user to increase fighting potential and enhances the users reflexes significantly, becoming the Skill Warrior (技戦士, Waza Senshi). When used, half of Kamen Rider Double becomes the black Ace Left Half (切り札の左半身, Kirifuda no Hidari Hanshin). During the events of W Forever, Shotaro receives Sokichi Narumi's Lost Driver, allowing him to become Kamen Rider Joker (仮面ライダージョーカー, Kamen Raidā Jōkā) on three occasions. This belt is retrieved by Philip and given to Shotaro before his disappearance, allowing him to become Kamen Rider Joker again.
• Metal (メタル, Metaru): The Metal Memory, also known as the Steel Memory (鋼鉄の記憶, Kōtetsu no Kioku) or the Fighter Memory (闘士の記憶, Tōshi no Kioku), empowers the user with great strength and magnified resistance to physical harm, becoming the Superpowered Warrior (怪力戦士, Kairiki Senshi). When used, half of Kamen Rider Double becomes the silver Fighter Left Half (闘士の左半身, Tōshi no Hidari Hanshin). Forms using the Metal Memory are armed with the extendable Metal Shaft (メタルシャフト, Metaru Shafuto) bō.
• Trigger (トリガー, Torigā): The Trigger Memory, also known as the Sniper Memory (銃撃手の記憶, Jūgekishu no Kioku), turns the user into an expert marksman, becoming the Gun Warrior (銃戦士, Jū Senshi). When used, half of Kamen Rider Double becomes the blue Sniper Left Half (狙撃手の左半身, Sogekishu no Hidari Hanshin). Forms using the Trigger Memory are armed with the Trigger Magnum (トリガーマグナム, Torigā Magunamu) handgun. When the Trigger Memory is placed in the Maximum Slot on the Trigger Magnum, the weapon changes from Normal Mode (ノーマルモード, Nōmaru Mōdo) to Maximum Mode (マキシマムモード, Makishimamu Mōdo) to fire an elemental-powered Maximum Drive attack.

Shotaro Hidari is portrayed by Renn Kiriyama (桐山 漣, Kiriyama Ren). As a child, Shotaro is portrayed by Issei Kakazu (嘉数 一星, Kakazu Issei), who also portrays Akira Aoyama (青山 晶, Aoyama Akira) in the television series' final episode.

The mysterious Philip (フィリップ, Firippu) is Shotaro's partner in the detective agency who lost his memory and uses his special abilities to access the Gaia Library to solve Dopant crimes. He was originally Raito Sonozaki (園咲 来人, Sonozaki Raito), the third child and only son of the Sonozaki family who died was revived as an avatar of the planet's consciousness Gaia Memory (地球の記憶, Chikyū no Kioku). Thus Raito was considered the "Chosen Child" (運命の子, Unmei no Ko) by his father Ryubee who had Satoshi Yamashiro wipe out the now ageless youth's memories of his former identity to be used by the Museum in the mass production of artificial Gaia Memories. After being rescued by Shotaro and Sokichi Narumi, the latter naming him after the fictional detective Philip Marlowe, Philip aids Shotaro to atone for being used as a puppet willingly by his captors. Normally remaining in the Detective Agency's secret hangar, reading at his spare time with a habit of becoming obsessed with a topic of interest, Philip investigates Dopant activities through his ability to access the Gaia Library (地球（ほし）の本棚, Hoshi no Hondana) and its Infinite Archive (無限アーカイブ, Mugen Ākaibu), a metaphysical realm and Akashic records in the form of white room filled with an endless number of books on an endless number of bookshelves.

While initially a logic-minded sociopath with little common sense who constantly irks all around him, Philip gradually becomes more empathic while eventually learning his former identity as a member of the Sonozaki Family. He was eventually captured and was absorbed by Wakana to restore the Museum's hold on the True Gaia Memory, later extracted by Shotaro. But the event renders Philip's body unstable to the point that should he transform into Kamen Rider Double again, he would break up into data and be completely absorbed by the planet once he cancels transformation. Saving their final transformation to save Wakana and fight Jun Kazu, Philip has Shotaro promise him that he will still fight for Futo even after he is gone. After Kazu is defeated, Philip bids his final farewell to Shotaro as he fades away once the transformation is cancelled. Before he left, Philip left Shotaro a gift containing a Lost Driver buckle and the blank book he used to bring around with him, containing a message thanking Shotaro and asking him to continue to protect Futo. However, after Wakana learns that Philip sacrificed his own physical existence to save her, she initiates her own Gaia Impact: sacrificing herself to bring back the Xtreme Memory and reconstruct Philip's physical body. Before returning, Philip has one last moment with his family who tell him that they will be watching over him. Once revealing himself a year after his physical form is completely restored, Philip resumes protecting Futo with Shotaro.

As Double, Philip possesses Gaia Memories called Soul Memories (ソウルメモリ, Souru Memori) which transfer his consciousness into Shotaro's body, providing both the right half of Double's body and his elemental power.

• Cyclone (サイクロン, Saikuron): The Cyclone Memory, also known as the Windy Memory (風の記憶, Kaze no Kioku), allows the user to move at fast speeds, controlling the very power of wind, becoming the Windy Warrior (風の戦士, Kaze no Senshi). When used, half of Kamen Rider Double becomes the green Cyclonic Right Half (旋風の右半身, Senpū no Migi Hanshin). Forms using the Cyclone Memory possess a silver scarf known as the Windy Stabilizer (ウィンディスタビライザー, Windi Sutabiraizā) hanging from the neck. During the events of the novel Kamen Rider W: The One Who Continues After Z, Philip uses the Lost Driver and the Cyclone Memory to transform into the wind-powered Kamen Rider Cyclone (仮面ライダーサイクロン, Kamen Raidā Saikuron).[1]
• Heat (ヒート, Hīto): The Heat Memory, also known as the Hot Memory (熱き記憶, Atsuki Kioku), empowers the user with the element of fire, becoming the Blazing Warrior (炎の戦士, Honō no Senshi). When used, half of Kamen Rider Double becomes the red Heated Right Half (熱き右半身, Atsuki Migi Hanshin).
• Luna (ルナ, Runa): The Luna Memory, also known as the Illusion Memory (幻想の記憶, Gensō no Kioku), allows the user to cast illusions, stretching limbs and bending gunshots, becoming the Mysterious Warrior (神秘の戦士, Shinpi no Senshi). When used, half of Kamen Rider Double becomes the gold Fantastical Right Half (幻想の右半身, Gensō no Migi Hanshin).
• The Fang Memory (ファングメモリ, Fangu Memori), also known as the Fanged Memory (牙の記憶, Kiba no Kioku), is a special Gaia Memory built to protect Philip and act on his orders, able to change between its Dromaeosaurid-like Live Mode (ライブモード, Raibu Mōdo) to Memory Mode (メモリモード, Memori Mōdo). When Philip uses the Fang Memory, he become the main body while Shotaro's consciousness is transferred into him. While this allows Philip to go out into the open and utilize Double's power in case Shotaro is physically unable to. Originally, the form tends to be a last resort as the transformation is extremely taxing on Philip's frail body while rendering him a berserker, prior to his revival at full health. Able to produce the bladed weapons on his body like the Arm Saber (アームセイバー, Āmu Seibā) and the removable Shoulder Saber (ショルダーセイバー, Shorudā Seibā).
  • The first Fang’s half form is FangJoker (ファングジョーカー, Fangu Jōkā). Because of Shotaro’s high synchronization with the Joker Memory, it keeps Fang from its berserk state, as the Gaia Memory itself was initially suited for hand to hand combat prior to Philip’s full revival at the end of the series. When using Maximum Drive, it produce Maximum Saber (マキシマムセイバー, Makishimamu Seibā) and used in for Fang Strizer (ファングストライザー, Fangu Sutoraizā).
  • FangTrigger (ファングトリガー, Fangu Torigā) is exclusive to the manga sequel Futo Detective, first appear in chapter 65. It allows its left-half to produce two Arm Sabers on both side of its wrist, acting as a bow. Once the Arm Saber bow is produced, Double can produce an energy arrow from the horn of Fang Memory. The Maximum Drive is Fang Screwdle (ファングスクリュードル, Fangu Sukurūdoru).

Philip is portrayed by Masaki Suda (菅田 将暉, Suda Masaki). As a child, Philip is portrayed by Tomoya Hashimoto (橋本 智哉, Hashimoto Tomoya).

Akiko Narumi (鳴海 亜樹子, Narumi Akiko) is Shotaro's boss and head of the Narumi Detective Agency. Because of her young appearance and attitude, Shotaro refers to her as "Middleschool Girl" (女子中学生, Joshi Chūgakusei) and sees her as a threat to his public image. She has come to Futo from Osaka to find her father and reclaim the agency's building, initially unaware that her father had died and was a Kamen Rider until the events of the Begins Night film. She serves as a personal assistant as well as the boss of the place while on the job as well as keeping Shotaro on the right track by slapping him with a green sandal; she has also used this tactic on other characters, including Dopants. She has a black and white view of the world and tends to say "I didn't hear of this!!!" (私聞いてない!, Watashi kiitenai!) when she is caught off guard by something. Despite her somewhat childish personality, she has shown signs of promise as a detective, particularly in her ability to decipher clues that leave Shotaro, Philip, and Ryu stumped, as well as being extremely protective of clients, a trait she shares with her father. Akiko harbors a crush on Ryu Terui, but her advances are ignored as he maintains a professional demeanor towards her, until he finally gives in to his feelings for her. However, she is ultimately torn due to unresolved issues with her father until the events of Kamen Rider × Kamen Rider OOO & W Featuring Skull: Movie War Core when she learns the full story of her father before her wedding to Ryu. During the events of Kamen Rider Accel, due to his inability to call her by name, Akiko believes that Ryu doesn't love her, further worsen after seeing Ryu on the run with Aoi Katsuragi, believing that he cheated on her. But when held captive by the Commander Dopant and saved by her husband, Akiko learns that Ryu truly loves her, though he insists to not call her by her name. In Drive Saga: Kamen Rider Chaser, it is revealed that Akiko and Ryu now have a daughter named Haruna Terui (照井 春奈, Terui Haruna).

Akiko Narumi is portrayed by Hikaru Yamamoto (山本 ひかる, Yamamoto Hikaru). As a child, Akiko is portrayed by Saho Ueda (上田 紗帆, Ueda Saho) in Kamen Rider Skull: Message for Double.

Sokichi Narumi (鳴海 荘吉, Narumi Sōkichi) is Shotaro's mentor and founder of the Narumi Detective Agency, referred by Shotaro as "Boss" (おやっさん, Oyassan). His policy with investigations is to ensure the client's safety above all else, and unlike Shotaro, he is truly hardboiled in the sense that he will make difficult decisions when he needs to, and follows through with it. However, during the events depicted in Kamen Rider × Kamen Rider OOO & W Featuring Skull: Movie War Core, Sokichi became involved in the Dopant cases and gaining the means to become Kamen Rider Skull (仮面ライダースカル, Kamen Raidā Sukaru) from Shroud, who is an old friend of his. Sokichi later accepts a job from Shroud to get Philip away from the Sonozaki Family, transforming into Skull to fend off the Taboo Dopant and an army of Masquerade Dopants during the raid on their factory. But in the end, after talking Philip into coming with him to decide his own fate and find his own atonement, Sokichi is shot in the back and dies telling Shotaro to continue in his place and giving him his white fedora, his dying words being for Shotaro to "grow into a man worthy of wearing it".

Sokichi Narumi is portrayed by Koji Kikkawa (吉川 晃司, Kikkawa Kōji).[2] Kikkawa also performs the song "Nobody's Perfect" under the name of his character.

Seiichiro Matsui (松井 誠一郎, Matsui Seiichirō), or simply known as "Matsu" (マツ), was Sokichi Narumi's former partner from the year 1999. He often helped in Sokichi's cases by researching in libraries, as he is described to be a "1999 version of Philip" by Akiko. But he had a bit of envy towards Sokichi for always getting the girl. Meeting with Melissa where she hires him to save her from Yaguchi, a chain of events occur that result in Matsu becoming one of the first Gaia Memory users initially to protect Melissa. However, the Spider Memory warps Matsu's mind to the point of him wanting Melissa for himself, as he always had feelings for her. As the Spider Dopant (スパイダー・ドーパント, Supaidā Dōpanto), he can use threads known as the Spider Net (スパイダーネット, Supaidā Netto) for attacks and other uses, as well as implanting little Spider Bombs (スパイダーボム, Supaidā Bomu) into humans that would spin silk around a person's loved ones and explode upon touch. Matsu dies after his Gaia Memory is destroyed in a fight with Sokichi as Kamen Rider Skull, who still calls him his "partner". He appears in the film Kamen Rider × Kamen Rider OOO & Double featuring Skull: Movie War Core, when the Pteranodon Yummy uses the Memory Memory to reveal the events of Sokichi Narumi's past.

His organization style in his research is the same style used in the continuation of an episode arc where it shows important individuals involved in the case (including themselves), how they relate to each other, and other possible clues to the case.

The Spider Dopant is an homage to the inhumanoid Spider Man (蜘蛛男, Kumo Otoko) from the original Kamen Rider television series.[3]

Seiichiro Matsui is portrayed by Tarō Yamamoto (山本 太郎, Yamamoto Tarō).[4]

Mikio Jinno (刃野 幹夫, Jinno Mikio) is a senior detective of the Futo Police working on the Dopant case who is very gullible, falling for the same trick every time until the Jewel Dopant case when he is arrested and vows to himself to be less gullible after being cleared of all charges. Despite his personality, he is a dedicated officer and sometimes wise. He also happens to be a friend of Shotaro's with whom he discusses cases, while unaware of his Shotaro's connection to Kamen Rider Double. It is implied that he has known Shotaro when he was younger as Shotaro recalls being chased by him when Jinno was an officer. He is almost never seen without his back scratcher. In Kamen Rider Accel, after taking down the Kamen Soldiers by himself, Jinno is shot with Ryu's firearm by the Commander Dopant. However, the wound is not fatal and he makes a complete recovery.

Mikio Jinno is portrayed by Takeshi Nadagi (なだぎ 武, Nadagi Takeshi).

Shun Makura (真倉 俊, Makura Shun) is Jinno's rookie partner, an unpleasant guy who is doubtful of Shotaro's skills and sees his involvement with police investigations unnecessary. He and Shotaro often get into fights when they are together, at times requiring Jinno to break them up. He is extremely impulsive, often jumping to conclusions when it comes to solving crimes and accusing people of committing crimes with little or no proof except from the word of a superior officer. He is nicknamed "Macky" (マッキー, Makkī) by Shotaro and the others.

Shun Makura is portrayed by Shingo Nakagawa (中川 真吾, Nakagawa Shingo).

Ryu Terui (照井 竜, Terui Ryū) is a young man who is a Superintendent appointed to the Futo Police Department's Paranormal Crime Investigation Division (超常犯罪捜査課, Chōjō Hanzai Sōsaka), much to the chagrin of Shotaro, Jinno, and Makura. Though he becomes an ally to Shotaro in fighting Dopant crimes as Kamen Rider Accel (仮面ライダーアクセル, Kamen Raidā Akuseru), Ryu originally becomes a Kamen Rider to find his family's murderer, Dr. Shinkuro Isaka. However, it is only after Isaka's death that Ryu learns that there is more to the story behind the death of his family.

Ryu Terui is portrayed by Minehiro Kinomoto (木ノ本 嶺浩, Kinomoto Minehiro).

Watcherman (ウォッチャマン, Wotchaman) is the username of an otaku blogger who is Shotaro's informant on Dopant activities. He also owns a bicycle called Futo-kun Bicycle (ふうとくんバイシクル, Fūtokun Baishikuru) that he won in a mail-in contest.[5] During the events of W Forever, Watcherman obtains the T2 Violence Memory and it forces him to become the T2 Violence Dopant (T2バイオレンス・ドーパント, Tī Tsū Baiorensu Dōpanto), whose left arm and Violence Ball form are pure destruction. After being restored by Double LunaJoker's Joker Strange Maximum Drive, Watcherman is taken to a free clinic where he stays during NEVER's attack.

Watcherman is portrayed by Nasubi (なすび).

Santa-chan (サンタちゃん) is a mysterious man who is seen throughout Futo, the owner of a pet shop who promotes local companies by giving out freebies in a Santa Claus outfit. He gives out presents which always seem to help out the recipient. During the events of W Forever, Santa-chan obtains the T2 IceAge Memory and it forces him to become the T2 IceAge Dopant (T2アイスエイジ・ドーパント, Tī Tsū Aisueiji Dōpanto), with the ability to make absolute zero ice. After being restored by Double LunaJoker's Joker Strange Maximum Drive, Santa-chan is taken to a free clinic where he stays during NEVER's attack. One year after the final battle with the Utopia Dopant, Santa-chan is seen as the owner of a pet shop that Shotaro visits, breaking up a fight between Shotaro and an unnamed employee who is later revealed to be the Energy Dopant. Though he is seen in a Santa Claus outfit almost all the time, he ironically dons a reindeer outfit on Christmas Day instead.

Santa-chan is portrayed by Zennosuke Fukkin (腹筋 善之介, Fukkin Zennosuke).

Queen (クイーン, Kuīn) and Elizabeth (エリザベス, Erizabesu) are two teenage girls who serve as Shotaro's informants in high school settings. Shotaro has known them since they're children and would often play together with them. The two are also singers, who get a major label release for their song "Love♡Wars". In Begins Night, it is revealed that Elizabeth has feelings for Philip. During the events of Kamen Rider W Forever: A to Z/The Gaia Memories of Fate, Queen is seen with the T2 Queen Memory (T2クイーンメモリ, Tī Tsū Kuīn Memori), which can be used to form a barrier around the user. The Gaia Memory attempts to take control of Queen and forms a Living Connector on her arm, but she is able to resist and throw the Memory away. Elizabeth also finds the T2 Accel, Key, and Bird Memories (referencing the real band the two actresses are a part of, AKB48), giving them to Shotaro without being affected by them.

Queen and Elizabeth are portrayed by Tomomi Itano (板野 友美, Itano Tomomi) and Tomomi Kasai (河西 智美, Kasai Tomomi), both former AKB48 members, respectively.[6]

Isamu Bito (尾藤 勇, Bitō Isamu), also known as "Sam" (サム, Samu) is a stallholder and an old client of Sokichi Narumi. He has a habit of flicking people painfully in the face with his hand when they say something that annoy him, which he often performed on Shotaro. Ten years ago, Bito took the heat for an armored car robbery involving the Beastman, actually his employee Maruo Arima and Suzuko Arima, a woman he had feelings for. However, after the case is solved, Bito continues with his job.

Bito appears in Kamen Rider × Kamen Rider OOO & W Featuring Skull: Movie War Core, where he owns a stall selling pinwheels in the year 1999. Bito introduces Sokichi to Stone to help him solve the "Spider Man" case.

Isamu Bito is portrayed by Kazuyoshi Ozawa (小沢 和義, Ozawa Kazuyoshi).

Stone (ストーン, Sutōn) is an architecture otaku who is introduced to Sokichi Narumi by Isamu Bito to help them solve the "Spider Man" case with his lock picking talents. Helping Sokichi sneak into the Yaguchi Talent Agency, Stone is captured and murdered by the Bat Dopant. He appears in the film Kamen Rider × Kamen Rider OOO & Double featuring Skull: Movie War Core when the Pteranodon Yummy uses the Memory Memory to reveal the events of Sokichi Narumi's past.

Stone is portrayed by Shiro Tsubuyaki (つぶやき シロー, Tsubuyaki Shirō).[7][8]

The Sonozaki Family (園咲家, Sonozaki Ke) is an aristocratic family in Futo who founded the organization known as the Museum (ミュージアム, Myūjiamu). When his son Raito died and was reborn as an avatar of the true Gaia Memory, Ryubee used his organization to produce and distribute the Gaia Memories created throughout the criminal underworld for experimentation, resulting in the Dopant crime waves. The ultimate goal of Museum is to use the data gathered for both the Dopants and the Kamen Riders to invoke an effect known as the Gaia Impact (ガイアインパクト, Gaia Inpakuto), which Ryubee plans based on his fears of humanity's extinction to make mankind one with the Earth itself.

With the exception of Raito and Fumine, each member of the Sonozaki Family owns a special Gaia Memory, called Gold Memories (ゴールドメモリ, Gōrudo Memori), allowing them to assume Dopant forms with the use of a prototype Gaia Driver (ガイアドライバー, Gaia Doraibā) belt which prevents the corruptive effects of usual Dopant Gaia Memories at the cost of reduced power. In the end, when Ryubee's plan almost succeeds, it results with the family estate burning to the ground, marking the end of both its patriarch and the Museum. At the end of the series, when Wakana sacrifices her body to give Philip (Raito) his body back, the family becomes a part of the Earth to watch over Philip and tasks him with the family duty to protect Futo and to change the world for the benefit of mankind.

Ryubee Sonozaki (園咲 琉兵衛, Sonozaki Ryūbee) is the seemingly wise yet maniacal head of the Sonozaki Family and leader of the Museum, who is almost always seen smiling or laughing. He sports a commanding presence and can adequately terrify many even without the use of his Terror Memory, which is the main reason why the police leaves him alone even though they have suspicions regarding his activities. He acts as a godfather in the organization and sees the entirety of the city of Futo as his personal kingdom, not letting anyone get in the way of his vision for the city, not even his wife and children. With the Terror Memory, Ryubee can transform into the Terror Dopant (テラー・ドーパント, Terā Dōpanto), who can increase the fear in his victims to maddening levels. He could also summon the Terror Field (テラーフィールド, Terā Fīrudo) to burn his victims or teleport himself and others across long distances and project his power into the Terror Crown (テラークラウン, Terā Kuraun) to create a Barong-like familiar known as the Terror Dragon (テラードラゴン, Terā Doragon). As the head of the Museum, Ryubee oversees the distribution of Gaia Memories, using those who can use them as research specimens, regardless of the harm and deaths that ensued. He does not seem to consider the Kamen Riders fighting the Dopant crimewave a threat, using the data off of them as a means to perfect his plans for Wakana before turning his attention to regain Philip and complete his plan to initiate the Gaia Impact.

It is revealed that Ryubee was an archaeologist who bought the grounds his estate was built on after finding deposits of fossils and relics beneath it, forming the collection at the Futo Museum where he works as its curator. He eventually discovered the location of the planet's consciousness, dubbed the Gaia Memory (地球の記憶, Chikyū no Kioku), and brought his family to see it. However, when his son Raito fell into the "fountain" of the Gaia Memory and died, but was somehow resurrected by the planet's powers, Ryubee began his plan for the Gaia Impact: an event that would ensure the future of the human race by making them one with the planet itself, much like his son had become. To reach his goal, he used an item dubbed the "Evil Tail" (イーヴィルテイル, Īviru Teiru), an archaeologist's brush with the names of his family inscribed on it, to overcome the fear that would go along with sacrificing them to reach his goal, eventually making him go mad. When he sacrifices Raito (Philip) once more into the Gaia Memory to make his daughter Wakana one with the Earth, he is confronted by both Kamen Riders. While Kamen Rider Accel as the AccelTurbuler destroys his Terror Dragon, Shotaro is able to retrieve Philip's mind and then his body from the aspects of the Gaia Memory in ClayDoll Xtreme to transform into Kamen Rider Double CycloneJokerXtreme to defeat the Terror Dopant and destroy the Terror Memory, along with most of the Sonozaki estate. With Ryubee's mind still broken from years of planning, he enters the still burning ruins of his home, glad that he finally initiated the Gaia Impact. He dies in the blaze, thinking of the good times he had with his family before he discovered the Gaia Memory and claiming that he has no regrets about his life as he dances madly by himself.

During the events of OOO, Den-O, All Riders: Let's Go Kamen Riders, Terror Dopant appears to be a member and leader of Shocker in normal timeline.

Ryubee Sonozaki is portrayed by Minori Terada (寺田 農, Terada Minori). In the music video for "Nobody's Perfect", the Terror Dopant make a cameo as he fights Kamen Rider Skull.[9][10]

Saeko Sonozaki (園咲 冴子, Sonozaki Saeko) the eldest of the Sonozaki children who runs an IT company called the Digal Corporation (ディガル・コーポレーション, Digaru Kōporēshon), which serves as a front for Gaia Memory production and distribution. As the Taboo Dopant (タブー・ドーパント, Tabū Dōpanto), she gains the ability to fly and generate deadly plasma balls. Ryubee strictly raised Saeko to believe that their family is superior to all others and that they are destined to rule the world. This loveless upbringing caused her to grow up secretly hating her father, often taking the resulting rage out on her younger sister Wakana, serving as fuel for her own ulterior motives of taking over the Museum to prove herself to her father to be its ideal successor. She also has a tendency to kill her boyfriends if they do not live up to her expectations. When Saeko spares Kirihiko due to his capabilities, she marries him and lets him live until he threatens the Museum's livelihood. He has no problems executing Kirihiko as she had never loved him. After Kirihiko's death, Saeko begins to visit Shinkuro Isaka to improve her Dopant form and focus on her plans for the Museum. After he is almost defeated by the Kamen Riders, she begins to show that she cares for Isaka's well-being, which is likely to be genuine attraction to the doctor. Once her coup against her father fails and Isaka is killed off, Saeko goes on the lam and is hunted down by the Smilodon Dopant, who takes the Taboo Memory and leaves her for dead. However, Saeko is saved by Kazu who offers his support in her scheme to take control of the Museum. After infiltrating the Digal Corporation, now with Wakana as its head, to obtain the Nasca Memory and then using an L.C.O.G on herself instead of using the Memory with a Driver. Without inhibitions posed by a Driver, Saeko is able to use the Gaia Memory in its Level 3 state to become the R Nasca Dopant (Rナスカ・ドーパント, Āru Nasuka Dōpanto, "R" for both "Red" and "Revenge") to overpower her sister. However, when Wakana evolves to ClayDoll Xtreme, which Saeko proves to be utterly powerless against, she is forced to go after other options to make herself more powerful, such as the Jewel Memory, before the Nasca Memory is destroyed in a confrontation with ClayDoll Xtreme. Later, after her father's death, Saeko is disillusioned until she learns of Wakana's survival and regains the Taboo Memory from Kazu after he announces that she has become the head of the Museum. However, no longer having a reason to prove herself with her father dead, Saeko fights Kazu in order to save her sister. As a result, the Taboo Dopant sacrifices herself to hold off the Utopia Dopant to give Wakana time to run away, resulting in Saeko's death as she finally admits the irony of her last moments in her final breath.

Saeko Sonozaki is portrayed by Ami Namai (生井 亜実, Namai Ami).[11][12]

Wakana Sonozaki (園咲 若菜, Sonozaki Wakana) is the youngest daughter and middle child of the Sonozaki family who since her brother's death has been secretly raised to become the key element in her father's plans. Working as a DJ at the local Wind Wave (ウインドウェーブ, Uindo Wēbu) radio station, she hosted the Wakana's Healing Princess (園咲若菜のヒーリングプリンセス, Sonozaki Wakana no Hīringu Purinsesu) show and gained a loyal fanbase as a result. While she puts up a shy and kind persona on the show or whenever a crowd is around, her true personality is the complete opposite. As a member of the Museum, Wakana is able to transform into the ClayDoll Dopant (クレイドール・ドーパント, Kureidōru Dōpanto), enabling her to produce gravitational energy shots, as well as the ability to reform her Dopant body after it is shattered into thousands of pieces. Out of all of the members of the Sonozaki Family, she is the least involved with the Gaia Memory business, as she was doted upon while growing up. After encountering Philip, Wakana begins to have second thoughts about being a Dopant and discards the ClayDoll Memory. It is returned to her by her father, who is aware that she did not lose it as she claims; he later decides to bring her into the family business after Kirihiko's death and is the one chosen to view the effects of the Xtreme Memory on the true Gaia Memory. Before this, Wakana also becomes one of Shinkuro Isaka's unwilling experiments after he modifies her Gaia Driver, subjecting her to more of her Gaia Memory's influence and its short term side effects showing her compatibility with its powers.

After trying to run away with Philip, her father takes her to the Museum's true base of operations. Made to believe by unknown means that she is serving a greater good for the planet's sake, Wakana runs the Museum and the Digal Corporation, bent on bringing Philip back to the Museum to complete the Gaia Impact. Her personality now resembles Saeko, but more ruthless and unforgiving. She is also given the Prototype Organic Information Controlling Organ Body Gaia Progressor (有機情報制御器官試作体・ガイアプログレッサー, Yūki Jōhō Seigyo Kikan Shisakutai Gaia Puroguressā), a device based on the Xtreme Memory that is designed to evolve her into the godlike ClayDoll Xtreme (クレイドールエクストリーム, Kureidōru Ekusutorīmu) to prepare her for the Gaia Impact so she become one with the planet's vast knowledge. While armed with tendrils and exponentially more power, Wakana becomes a being like Philip with access to the true Gaia Memory, much like CycloneJokerXtreme. When the Gaia Impact seems to succeed after Philip is thrown into the source of the true Gaia Memory, becoming a living Gaia Memory and fully integrated with the ClayDoll Memory, Wakana loses control when Philip is removed from her body, causing an explosion that destroys the Sonozaki estate. However, in midsts of the blaze, Wakana's unconscious body is carried off by Kazu to the Foundation X research facility to be of use in his own version of the Gaia Impact. However, Shotaro manages to save her before taking her to the hospital. A few days later, Wakana attempts to force her way out of the hospital to resume her family's goal before finally learning that Philip disappeared into the Gaia Memory to save her. After getting the means to invoke the Gaia Impact from Shroud in her final moments, Wakana sacrifices her own existence to bring her brother back via the Xtreme Memory.

Wakana Sonozaki is portrayed by Rin Asuka (飛鳥 凛, Asuka Rin). As a young child, Wakana is portrayed by Natsuki Kasa (笠 菜月, Kasa Natsuki).[13][14]

Kirihiko Sudo (須藤 霧彦, Sudō Kirihiko) is a young man who initially works for the Museum as one of its best Gaia Memory dealers. He also has a professed love of the city of Futo, and in his youth created the city's mascot Futo-kun (ふうとくん, Fūtokun). In his work with the Museum, Kirihiko eventually catches the eye of Saeko and they marry, taking on the Sonozaki surname in place of his own. In being welcomed into the family, he is granted a Gaia Driver along with the ability to become the Nasca Dopant (ナスカ・ドーパント, Nasuka Dōpanto), an expert swordsman armed with the Nasca Blade (ナスカブレード, Nasuka Burēdo) with the powers of flight from the Nasca Wings (ナスカウイング, Nasuka Uingu). As an in-law, Kirihiko is not as fully aware of the truth behind the family business or Kamen Rider Double's existence until confronting him in battle. He eventually discovers that Shotaro is Double, and begins to confront him as a rival to test his Gaia Memory's powers. When he finally discovers the truth behind the Gaia Memories, while suffering near-lethal side effects from eventually reaching Level Two of the Nasca Memory's powers, he tries to take Saeko away from the Museum, but she kills him as he is now a threat to her future plans. Saeko kept his Nasca Memory, eventually using it to transform into the R Nasca Dopant before it was destroyed by ClayDoll Xtreme. In episode 33, it was revealed that he had a sister, Yukie Sudo.

Kirihiko Sudo is portrayed by Yuki Kimisawa (君沢 ユウキ, Kimisawa Yūki).[15]

Mick (ミック, Mikku) is Ryubee's beloved pet blue British Shorthair, named by his son Raito (Philip). Despite being a cat, the Smilodon Memory can transform Mick into the humanoid Smilodon Dopant (スミロドン・ドーパント, Sumirodon Dōpanto) that can discharge electricity and move at blinding speeds, fast enough to evade the homing shots of Kamen Rider Double LunaTrigger and outmaneuver Kamen Rider Accel Trial. He appears to be more intelligent than the average house cat, in that he appears to know that he is able to transform into the Smilodon Dopant and he knows how to transform back into a house cat at will. He is often utilized by the Sonozaki Family to deal with matters outside their estate, such as hunting down Philip and traitors, as well as bodyguard and spy. Mick also appears to favor Wakana over the other members of the family though will faithfully follow Ryubee's orders. While targeting Kyoko, the Smilodon Dopant defeats Accel Trial before Double CycloneMetal catches the cat off guard before destroying his Gaia Driver and Smilodon Memory with the Metal Stag Break Maximum Drive. After Ryubee's death, Mick is brought to live at the Narumi Detective Agency.

Mick is played by a cat named Buri-chan (ブリちゃん). The Smilodon Dopant's vocalizations are performed by Yasuhiro Takato (高戸 靖広, Takato Yasuhiro).[16]

Masquerade Dopants (マスカレイド・ドーパント, Masukareido Dōpanto) are Dopants used by the Sonozaki family as guards and other forms of agents, and later used by the Foundation X. Mass-produced Masquerade Memories are distributed to their Gaia Memory salesmen for the purpose of producing more thugs to do their dirty work. The Masquerade Dopants differ from other Dopants as they retain human form, wearing a masks that have a spine and rib cage design, resembling the bony design of the Dopant Gaia Memories. Masquerade Dopants are also significantly weaker than other Dopants, devoid of any special abilities and can be sufficiently fought against by normal humans. Unlike more advanced Dopants as well, they are completely destroyed when taken down with sufficient force, which can be done without using a Maximum Drive.

Father Roberto Shijima (ロベルト志島, Roberuto Shijima), a major antagonist in Kamen Rider × Kamen Rider W & Decade: Movie War 2010, is a Catholic priest and a figure within the cult known as the Order of Silence and Darkness (闇と静寂の会, Yami to Seijaku no Kai). Shijima can become the Dummy Dopant (ダミー・ドーパント, Damī Dōpanto) who can assume any form he wishes. Among these forms is the Death Dopant (デス・ドーパント, Desu Dōpanto), using his powers to mimic the real Death Dopant's ability to bring people back from the grave. Using the Death Dopant's form, Father Shijima targets upper-class people by assuming the forms of their recently deceased relatives to frighten them and push them to an early grave. He uses this power on Asami Mutsuki by assuming the identity of her sister Erika, while assuming Sokichi Narumi's form to discourage Shotaro's interference. Once exposed, the Dummy Dopant evades Double as he finds himself in the middle of Decade's fight with Super Shocker, where he takes control of the Mammoth Mecha (マンモスメカ, Manmosu Meka). However, the Dummy Dopant meets his end when he is assimilated by the Neo Organism as it becomes the inhuman Ultimate D. Shijima only appears in Kamen Rider × Kamen Rider W & Decade: Movie War 2010. In materials to promote the film, the Dummy Dopant was referred to as the "mysterious Dopant" (なぞのドーパント, nazo no Dōpanto).

Roberto Shijima is portrayed by Toru Tezuka (手塚 とおる, Tezuka Tōru).

Shinkuro Isaka (井坂 深紅郎, Isaka Shinkurō) is the head physician at the Isaka Medical Clinic (井坂内科医院, Isaka Naika Iin). Ten years ago, finding no meaning in his life, he encountered Ryubee Sonozaki attacking a group of people as the Terror Dopant. This brings maddening joy to the doctor and he made a point to get the Terror Memory for himself, experimenting on himself with numerous Gaia Memories with various Living Connectors on his body before Shroud gave him the Weather Memory in the hope that he would be powerful enough to eliminate Ryubee. As the Weather Dopant (ウェザー・ドーパント, Wezā Dōpanto), he is armed with the whip-like Weather Mine (ウェザーマイン, Wezā Main) and control over the weather: intense sunlight, heavy rain, lightning, tornadoes, and freezing snow. He originally tested these abilities in a series of murders which include Ryu Terui's family, to whom he is only known as the man with the W Memory (Ｗ（ダブリュー）のメモリを持つ男, Daburyū no Memori o motsu otoko). Isaka does not use a Gaia Driver, as he feels he doesn't need the protection provided, as he is unaffected by their corruption due to him being already intensely psychotic, and the limits imposed on the power of Gaia Memories annoy him greatly. The Weather Dopant can also withstand Maximum Drives, as he has augmented the Weather Memory with other Gaia Memories' powers. This skill and his knowledge of Dopant physiology makes him an ally to the Museum. After his identity is discovered during his failed attempt to add the Invisible Memory to his arsenal, Isaka takes refuge in the Sonozaki estate where he convinces Saeko to take out her father so she can control the Museum and he can get the Terror Memory. Though he originally sees Saeko as merely one of his pawns and research material, he admits to having developed feelings for her. During his attempt to absorb the Quetzalcoatlus Memory, the Weather Dopant is finally defeated by Kamen Rider Accel Trial's Machine Gun Spike Maximum Drive, shattering the Weather Memory. Shortly afterwards, Isaka's excessive use of Gaia Memories causes his body to become covered in Living Connectors that dissolve him away into nothingness as he tells the Kamen Riders that Shroud will be their end. Shroud later expressed regret to Ryu for giving Isaka the Weather Memory, having no idea of what a monster he would become with the Memory.

Shinkuro Isaka is portrayed by Tomoyuki Dan (檀 臣幸, Dan Tomoyuki).[17]

Eren Komori (小森 絵蓮, Komori Eren) is the Gaia Memory dealer of the Museum during 1999. By using the Bat Memory, she can become the Bat Dopant (バット・ドーパント, Batto Dōpanto). As the Bat Dopant, she can use her ultrasonic voice to control vehicles such as a tank truck. She is defeated by Skull using the Skull Punisher to trap her under a truck she was using to fight him. Though she begs for his mercy in letting her go, Skull leaves her to die as the vehicle bursts into flames. She appears in the film Kamen Rider × Kamen Rider OOO & Double featuring Skull: Movie War Core, when the Pteranodon Yummy uses the Memory Memory to reveal the events of Sokichi Narumi's past.

The Bat Dopant is an homage to the inhumanoid Bat Man (蝙蝠男, Kōmori Otoko) from the original Kamen Rider television series.

Eren Komori is portrayed by Reon Kadena (かでな れおん, Kadena Reon).[4]

Hiroshi Sagami (相模 広志, Sagami Hiroshi) is the main antagonist of Kamen Rider Accel, a corrupt police officer within the ranks of the Futo police force. Three years prior to the storyline, Sagami lost his wife when she was gunned down by a criminal he arrested prior. Furious with the conclusion that law itself can never reform criminals, Sagami obtained the Commander Memory and becomes judge, jury, and executioner as the Commander Dopant (コマンダー・ドーパント, Komandā Dōpanto), executing any criminals he comes across regardless of the severity of their crimes. Known as the One Dopant Army (ワン・ドーパント・アーミー, Wan Dōpanto Āmī), the Commander Dopant can create Kamen Soldiers (仮面兵士, Kamen Heishi, Masked Soldiers) to fight for him with his gauntlet that materializes and destroys matter. After obtaining the Gaia Memory Enhancing Adapter from Aoi, the daughter of a petty thief he murdered in cold blood, the Commander Dopant acquires an upgraded form with the ability to fire a barrage of missiles. Seeing Ryu as a kindred spirit, Sagami kidnapped Akiko to force Ryu to open his heart back to brutal vengeance, making himself the villain and intends to have Ryu succeed his work. However, refusing to go down that path again, Ryu manages to get the Gaia Memory Enhancing Adapter and uses it to save his wife and defeat the Commander Dopant. Afterwards, Sagami was taken into custody.

Hiroshi Sagami is portrayed by Minoru Tanaka (田中 実, Tanaka Minoru).

• Yousuke Togawa (戸川 陽介, Togawa Yōsuke): A young man fired from his position at Windscale (ウインドスケール, Uindosukēru) before acquires the Magma Memory which imbues him with pyrokinetic powers that he intends to use to exact his revenge as the Magma Dopant (マグマ・ドーパント, Maguma Dōpanto). But Yousuke ends up being consumed by the Gaia Memory's power and goes on a rampage before Shotaro intercepts him at the fifth Windscale building and defeats him as Kamen Rider Double CycloneJoker. Before Yousuke can be handed over to the police, he is abducted and murdered by the T-Rex Dopant. Yousuke Togawa is portrayed by YOH.[18]
• Marina Tsumura (津村 真里奈, Tsumura Marina): Yousuke's girlfriend who was also fired from her position as Windscale's top designer, buys the T-Rex Memory to exact revenge alongside her boyfriend Yousuke as the T-Rex Dopant (ティーレックス・ドーパント, Tīrekkusu Dōpanto). In her Dopant form, the T-Rex Dopant can cause massive shockwaves with its roars and can use debris to form a robotic T. rex body called the Big T-Rex (ビッグ・ティーレックス, Biggu Tīrekkusu) to increase its powers. When Yousuke goes berserk, Marina hires her childhood friend Shotaro to track Yousuke and kills him the moment he was found and defeated. After Shotaro learns the truth, Marina tries to kill him as well before transforming into the Big T-Rex and leading Double on a chase around the city. As Kamen Rider Double, Shotaro destroys the T-Rex Memory with HeatMetal's Metal Branding Maximum Drive and hands Marina over to the authorities. Marina Tsumura is portrayed by Meibi Yamanouchi (山内 明日, Yamanouchi Meibi).[19] As a child, Marina is portrayed by Emiri Yagi (八木 瑛美莉, Yagi Emiri)[20]
• Taizo Kaga (加賀 泰造, Kaga Taizō): A lifelong gambler who is able to use others' tells to win. He is also the owner of the secret Million Colosseo (ミリオンコロッセオ, Mirion Korosseo) casino, using his powers as the Money Dopant (マネー・ドーパント, Manē Dōpanto) to enforce payment of debts. By tricking debtors into having them bet their life force in a game of chance, he uses his powers to seal their life force into pseudo-memories called Life Coins (ライフコイン, Raifu Koin) after they lose. As he holds the Life Coins in his Dopant body, his destruction would cause all of the people to die. Shotaro and Philip are able to beat Kaga out of Life Coins in a winner takes all game of old maid. After the Money Dopant is defeated and the Money Memory broken by means of the Metal Branding Maximum Drive, the Life Coins are unsealed and everyone is returned to normal. Taizo Kaga is portrayed by Tatsuya Gashuin (我修院 達也, Gashūin Tatsuya).[21]
• Genzo Takamura (鷹村 源蔵, Takamura Genzō): The childish head of one of the many Gaia Memory manufacturing centers scattered throughout Futo. As the Anomalocaris Dopant (アノマロカリス・ドーパント, Anomarokarisu Dōpanto), he can travel underwater, fire his fangs as if they are bullets, and transform into the Giant Anomalocaris (巨大アノマロカリス, Kyodai Anomarokarisu). Due to the fact that councilwoman Miyabi Kusuhara is continuing her late husband's plans to build the Second Futo Tower and Ryubee Sonozaki sees it as a threat to his enterprise, Takamura is given the order to assassinate her. After giving a proto-model of his Anomalocaris Memory, a production-model, to his friend so he can serve as a decoy (defeated by Kamen Rider Double's Joker Extreme), Genzo later kidnaps the councilwoman's daughter Asuka to lure her mother into a trap. However, the Anomalocaris Dopant is defeated by Kamen Rider Double LunaTrigger and his Trigger Full Burst Maximum Drive. Genzo Takamura is portrayed by Takaaki Ito (伊東 孝明, Itō Takaaki).[22]
• Ikari (伊刈): A sociopathic dōjinshi artist who runs the Dark Bug Exterminator website, a blog where people write down the names of those they want dead and he carries out the deed as the Cockroach Dopant (コックローチ・ドーパント, Kokkurōchi Dōpanto), writing about his adventures in his self-published manga as the hero "Gokistar" (ゴキスター, Gokisutā).[23] His Dopant abilities include the ability to climb along walls and to move faster than oncoming attacks, much like a cockroach. Only Kamen Rider Double LunaTrigger's homing attacks are able to hit him, but with his speed he steals the Luna, Trigger, Heat, and Metal Memories from Double. Ikari then decided to take the rest of Double's arsenal to become more powerful. However, after Philip learns the Heaven's Tornado dance and uses it against the Cockroach Dopant, the Gaia Memories are retrieved, allowing for the Cockroach Memory to be destroyed by LunaTrigger's Trigger Full Burst Maximum Drive. Ikari is portrayed by Jin Katagiri (片桐 仁, Katagiri Jin).[24]
• Yukiko Sasaki (佐々木 由貴子, Sasaki Yukiko): A maid at the Sonozaki estate with a sweet tooth that she cannot satisfy, only able to be a food critic instead of a pâtissière because she could not cook very well. In her Dopant form, she is able to fire a whip cream that hardens like cement to trap her enemies. As the Sweets Dopant (スイーツ・ドーパント, Suītsu Dōpanto), Yukiko kidnaps the top pâtissiers hired by the Sonozaki family by dragging them in her "Sweets Cream" (スイーツクリーム, Suītsu Kurīmu) state to a small building on the grounds to make pastries only for her. However, when Akiko attempts to weed out the wrong culprit with her sweets, Yukiko kidnaps her with Mai Asakawa, the daughter of her previous victim. Though intending to kill Akiko for disgracing her love for sweets, the Sweets Dopant is battered by Akiko using a chair before Kamen Rider Double finishes her off with HeatJoker's Joker Grenade Maximum Drive. Another Sweets Dopant appears in Kamen Rider W Returns's Kamen Rider Eternal entry, transforming from a man named in the credits as the "Sweets Man" (スイーツの男, Suītsu no Otoko). Yukiko Sasaki is portrayed by Maha Hamada (濱田 万葉, Hamada Maha), while second Sweets Dopant is portrayed by Kamen Rider W's head writer Riku Sanjo (三条 陸, Sanjō Riku).[25]
• Virus Dopant (バイラス・ドーパント, Bairasu Dōpanto): A Dopant normally turns its user into the vector of a deadly plague that can wipe out entire cities. However, when Sachi Yamamura (山村 幸, Yamamura Sachi) uses the Virus Memory to save herself from a hit and run, the transformation into the Virus Dopant is interrupted leaving only her consciousness fully enveloped in the Gaia Memory's corruptive influence. These events weaken the Virus Dopant, but also enables it to infect electronics. This ability leads to the creation of the "Infected Car" (感染車, Kansensha), a formerly wrecked SUV that infects a human with its deadly virus upon impact. When the car is wrecked by Kamen Rider Double, the Virus Dopant begins using its physical form to exact Sachi's revenge on her ex-fiancé who she learned was only a con man. After discovering the Virus Dopant's vulnerability to heat, Double HeatTrigger's Trigger Explosion Maximum Drive destroys the Dopant's physical body, causing the Virus Memory's ejection from Sachi's body and its Memory Break. Sachi Yamamura is portrayed by Rinako Matsuoka (松岡 璃奈子, Matsuoka Rinako).[26]
• Tsuyoshi Ageo (上尾 強, Ageo Tsuyoshi): Wakana's manager, a weak willed man who loves her in spite of the abuse. Ageo is used by Wind Wave DJ Motoko Saeki (佐伯 素子, Saeki Motoko) in a scheme to force Wakana off the air, giving him the Violence Memory she buys. Overcome by the Memory's influence, Ageo assumes the alias of "Mister Question" (ミスター・クエスチョン, Misutā Kuesuchon), targeting certain places of value to Wakana and portraying himself as a stalker. As the brutish Violence Dopant (バイオレンス・ドーパント, Baiorensu Dōpanto), his left arm is strong enough to destroy anything in its path, even enough to smash through cars. He can compress his body into a wrecking ball-like form called the Violence Ball (バイオレンスボール, Baiorensu Bōru) to cause more collateral damage. Once discovered, he abducts Wakana and is chased after by Kamen Rider Double. Before being defeated by means of LunaTrigger's Trigger Stag Burst Maximum Drive, he leads Wakana to Motoko. Tsuyoshi Ageo is portrayed by Hiromichi Miyoshi (三好 博道, Miyoshi Hiromichi).[27]
• Kenji Kurata (倉田 剣児, Kurata Kenji): Partnered with Fuyumi Aso (麻生 冬実, Asō Fuyumi) as the Twin Rose (ツインローズ, Tsuin Rōzu) burglar deo, Kenji was hired by Saeko to lure Philip out of hiding. Given the Arms Memory, it turns Kurata into an uncontrollable sadist as he turns his back on Fuyumi and the morals they followed. The Arms Dopant (アームズ・ドーパント, Āmuzu Dōpanto) is able to morph his left forearm into a variety weapons such as a gun and carries around a giant blade-like weapon called the Shield Sword (シールドソード, Shrīudo Sōdo). The Arms Dopant has his own personal Honda Valkyrie motorcycle called the Arms Bike (アームズバイク, Āmuzu Baiku). The Arms Dopant goes on a burglary spree and claims to be a Kamen Rider to force Double into the trap, only able to capture Shotaro and Akiko to use as hostages. However, the unexpected return of Kamen Rider Double FangJoker, and eventual control of the form, turns the tables with the Fang Streiser Maximum Drive as the defeated Kurata is left for the police. Kenji Kurata is portrayed by Koichiro Nishi (西 興一朗, Nishi Kōichirō).[28]
• Akane Egusa (江草 茜, Egusa Akane): A middle school girl selected by Saeko to test the limits of one of the newest Gaia Memories: the Bird Memory. In addition to the fact that no one under the age of 20 is allowed to use a Gaia Memory, the Bird Memory can also be used by those without a Living Connector and it has an addictive side effect. When Akane runs away from home, her friend Toma Fujikawa (藤川 統馬, Fujikawa Tōma) is the first to test the true powers of the Bird Memory out and decides to use it for fun with friends Yuichi Kanamura (金村 有一, Kanamura Yūichi) and Yayoi Kubota (久保田 弥生, Kubota Yayoi) until Toma decides to use it to attack people as the Bird Dopant (バード・ドーパント, Bādo Dōpanto). They are stopped by Kamen Rider Double, and the two boys are taken into the hospital after suffering from some of the negative side effects of using a Gaia Memory without a Living Connector. Later, Akane is overpowered by withdrawal from the Bird Memory and attacks Philip who gets in her way of obtaining it. Consumed completely by the Gaia Memory, Akane is able to access the Bird Dopant's Strengthened Form (強化態, Kyōkatai), only to be defeated after the Nasca Dopant assists Kamen Rider Double in finding the Bird Dopant's weak spot for a direct strike on the Bird Memory by means of CycloneTrigger's Trigger Bat Shooting Maximum Drive. Akane Egusa is portrayed by Mana Konno (今野 真菜, Konno Mana) while Toma Fujikawa, Yuichi Kanamura, and Yayoi Kubota are portrayed by Haruki Kimura (木村 遼希, Kimura Haruki), Takuya Yoshihara (吉原 拓弥, Yoshihara Takuya), and Manami Ikura (伊倉 愛美, Ikura Manami) respectively.[29]
• Kiyoshi Katahira (片平 清, Katahira Kiyoshi): The son of flower coordinator Makiko Katahira (片平 真紀子, Katahira Makiko), who received bad press due to her son's actions. Obtaining the IceAge Memory to become the IceAge Dopant (アイスエイジ・ドーパント, Aisueiji Dōpanto) with the ability to make absolute zero ice from attacks to clones, Kiyoshi uses it to attack anyone who makes him mad such as Shotaro when he unintentionally shoved Kiyoshi out of the way while looking for Makiko. After his clone is destroyed by Accel's Accel Glanzer Maximum Drive, believing the Dopant to be the one he is looking for, Kiyoshi runs into his mother as she takes the Gaia Memory from him to take the blame for the attack. However, Shotaro uncovers the truth as IceAge Dopant is defeated by Accel's Dynamic Ace Maximum Drive and Ryu Terui arrests Kiyoshi instead of killing him in revenge, only to learn that Kiyoshi is not his target when he discovers that he possesses the IceAge Memory and not the W Memory. Up until this time, the IceAge Dopant is only referred to as the icy Dopant (氷のドーパント, Kōri no Dōpanto). Kiyoshi Katahira is portrayed by Kento Shibuya (渋谷 謙人, Shibuya Kento).[30]
• Aya Kujo (九条 綾, Kujō Aya): A former FPD officer who transferred to the LAPD under encouragement from her partner Masaki Mizoguchi, whom she loved. After the scrutiny and disappearance of Mizoguchi, Aya returns to Futo and purchases the Triceratops Memory in order to take revenge against the men responsible for Mizoguchi's disappearance and death: the crooked cops Himuro and Ken Akutsu. As the Triceratops Dopant (トライセラトップス・ドーパント, Toraiseratoppusu Dōpanto), she possesses superhuman strength, can generate spheres of plasma, and uses the Dinosaur Club (ダイノソアクラブ, Dainosoa Kurabu) as her weapon. However, after killing off Himuro and Akutsu, Aya's revenge shifts to Futo as the Gaia Memory's corruptive powers begin to take hold. She eventually gains the ability to transform into a giant bipedal Triceratops called the Big Triceratops (ビッグ・トライセラトップス, Biggu Toraiseratoppusu) before Accel stops her with the AccelGunner and its Gaia Cannon. Aya Kujo is portrayed by Ayumi Kinoshita (木下 あゆ美, Kinoshita Ayumi).[31]
• Sachio Sawada (沢田 さちお, Sawada Sachio): A street calligrapher and poet who uses the Liar Memory to become the Liar Dopant (ライアー・ドーパント, Raiā Dōpanto), labeled in urban legends as the "Radio Tower Clown" (電波塔の道化師, Denpatō no Dōkeshi). the Liar Dopant uses his speaker-based Lie Speaks (ライスピークス, Rai Supīkusu) staff to converting any lie he says into Lie Needles (ライニードル, Rai Nīdoru) which compel the inflicted to fall under the Dopant's deception. While he was hired by Yukiho to help Jimmy win the Fuuuuuutic Idol (フーティックアイドル, Fūtikku Aidoru) competition, Sawada turns on her for her failure to pay his ideal amount and reveals the ruse in front of Jimmy. But once his cover is blown, along with his fandom for Wakana's radio show used against him, the Liar Dopant is overwhelmed and defeated by Double and Accel. Sachio Sawada is portrayed by Moro Morooka (モロ師岡).[32]
• Keio Horinouchi (堀之内 慶應, Horinouchi Keiō) is a children's author who has gained commercial success for his book The Girl and the Dollhouse (少女と人形の家, Shōjo to Ningyō no Ie) which he wrote to reflect his feelings for his daughter Rikako who died one month ago. As the Puppeteer Dopant (パペティアー・ドーパント, Papetiā Dōpanto), he uses special puppet strings to take control of whatever he wishes and carries a flute that produces super-sonic waves. He uses these powers to take revenge against those who give his book harsh criticism by controlling his daughter's doll, Riko, as the instrument of his vengeance. He particularly seeks revenge against those who claim he did not truly love his daughter. After being exposed, getting a new puppet in Wakana by Isaka, Horinouchi turns his attention towards Akiko before being defeated by Double CycloneMetal's Metal Twister Maximum Drive. Keio Horinouchi is portrayed by Wataru Shihoudou (四方堂 亘, Shihōdō Wataru).[33]
• Hajime Fukushima (福島 元, Fukushima Hajime) is a college student at Futo University who fell in love with Himeka Yukimura when she called him her "prince". However, he soon realizes that Himeka tells this to any male who assists her, plaguing him with the thought that she will never love him back and giving him insomnia as a result. He acquires the means to become the Nightmare Dopant (ナイトメア・ドーパント, Naitomea Dōpanto) in order to inflict this same pain on Himeka, by making sure she does not get a good night's sleep in fear of his attacks. In his Dopant form, Fukushima uses his dream manipulation powers to trap all of his rivals for Himeka's affections in their worst nightmares before using a massive dreamcatcher-like net to place them in a coma. Each victim is branded with a letter H on their foreheads, standing for both "Himeka" and "Hajime". Though he fakes being among the victims to get Shotaro off of his trail, Fukushima is found out and his Nightmare Memory is destroyed by Double LunaMetal's Metal Illusion Maximum Drive. Hajime Fukushima is portrayed by Koki Kato (加藤 康起, Katō Kōki).[34]
• Maruo Arima (有馬 丸男, Arima Maruo), also known as "Maru" (マル), is a bank robber who a decade ago gained the Beast Memory and became the Beast Dopant (ビースト・ドーパント, Bīsuto Dōpanto) with superhuman strength and self-regenerative powers. Attempting an armored car robbery at the Futo Dam with his wife Suzuko, the case was investigated by Sokichi Narumi until the evidence went dry and when Isamu Bito turned himself in for the crime. By the present, now rich, Maruo is still looking for a bear statue that holds the Zone Memory. Once it returns to Suzuko's possession, the two return to the Futo Dam to finish their heist. However, the Beast Dopant is weakened by Double CycloneJoker Xtreme's Prism Break Maximum Drive before being eventually defeated by the Bicker Charge Break Maximum Drive. Maruo Arima is portrayed by Katsuya (勝矢).[35]
• Suzuko Arima (有馬 鈴子, Arima Suzuko), also known as "Bell" (ベル, Beru), uses the powers of the Zone Dopant (ゾーン・ドーパント, Zōn Dōpanto) to teleport anything she sees in a similar method in moving the pieces of a shogi board. Ten years ago, Suzuko used these powers to assist her husband in his crime wave before she lost the Zone Memory, later found by Sokichi Narumi who then hid it in a bear statue he kept in a vacation cabin. The Zone Dopant is also the first Dopant to have no humanoid form at all, resembling a floating pyramid with an eye at the top. When Shotaro finds it, he confronts Suzuko about having Isamu Bito take the punishment for her crime before she takes it back, enabling her to help Maruo out once more in his battle against Kamen Rider Accel. She is defeated by Double CycloneJoker Xtreme's Bicker Finallusion Maximum Drive. Suzuko Arima is portrayed by Ryoko Gi (魏 涼子, Gi Ryōko).[36]
• Yukie Sudo (須藤 雪絵, Sudō Yukie) is the younger sister of Kirihiko who comes to Futo to take revenge against Saeko for her brother's death. With the powers of the Yesterday Dopant (イエスタデイ・ドーパント, Iesutadei Dōpanto), she is able to force anyone to repeat their actions from the previous day, before the target becomes comatose. Unlike other Dopants, Yukie is not driven insane by the Gaia Memory's influence, which allows her to choreograph her attacks to suit her needs. After attacking several landsharks attempting to buy the kindergarten she and Kirihiko attended, she approaches the Narumi Detective Agency as Yuko Fuwa (不破 夕子, Fuwa Yūko, resembling the English phrase "Who are you?") looking for her lost cat Kinou (きのう, Kinō, literally meaning "Yesterday"). Shotaro takes on the case, allowing Yukie to manipulate his actions as Double to attack Saeko the following day, but Accel saves her at the last minute. Yukie's identity is revealed, and she states that the attack is actually an audition to join the Museum. When she gets close enough to Saeko to exact her revenge, her powers are turned back to her due to Isaka's modifications of the Taboo Memory for such an attack. She is saved after CycloneJoker Xtreme's Prism Break destroys the Yesterday Memory, but its side effects finally manifest in total amnesia. Yukie Sudo is portrayed by Kaoru Hirata (平田 薫, Hirata Kaoru).[37]
• "Grasshopper Woman" (イナゴの女, Inago no Onna): A hitwoman who works for the museum as one of its top two eliminators along with the Smilodon Dopant, originally a normal girl until her mind was rewritten by neuroscientist Satoshi Yamashiro who was kidnapped to serve as a Museum researcher. She has purple hair, is dressed in Gothic Lolita attire, and carries a heart-shaped box full of boiled grasshoppers (いなごの佃煮, inago no tsukudani) that she eats and offers to others, often before attacking with her electroshock boots if they turn her down. As the Hopper Dopant (ホッパー・ドーパント, Hoppā Dōpanto), she is able to jump and kick with great intensity. She is called upon by Ryubee to murder Yamashiro when he escapes from the museum. After mortally wounding Yamashiro, the Hopper Memory is destroyed through Accel Trial's Machine Gun Spike Maximum Drive. Before Ryu can arrest her, the girl attempts to escape when the Smilodon Dopant kills her so she can not reveal any sensitive information concerning the Museum. The Grasshopper Woman is portrayed by Minami Tsukui (佃井 皆美, Tsukui Minami).[38]
• Toru Kawai (川相 透, Kawai Tōru): An extremely shy independent film director who becomes the Gene Dopant (ジーン・ドーパント, Jīn Dōpanto), able to use the DNA Mixer (DNAミキサー, Dī Enu Ē Mikisā) on his right arm to alter the genetic makeup of anything he touches. Using his power, he made his magnum opus on his own and then tricked theater goers into an empty room to sit through the 7-hour uncompleted film. After being easily defeated, Akiko decides to rehabilitate him by taking control of the movie's production, while trying to hook him up with its star Ai Nijimura who he impersonated beforehand, but this only upsets Toru due to Ai's character being rewritten from the dark figure as originally intended. However, after being used by Wakana to fuse the Gaia Progressor into her body and Akiko beating sense into him, Toru finally speaks his mind. Soon after, Toru gives up the Gene Memory, which is crushed to bits by Kamen Rider Double CycloneJoker Xtreme, and begins working on the movie in his own way with Ai. Toru Kawai is portrayed by Naoki Kawano (川野 直輝, Kawano Naoki).[39]
• Makoto Uesugi (上杉 誠, Uesugi Makoto): A popular male model who had a perversed sense of love. When his high school friend Rui Jojima falls in love with their friend Satoru, Uesugi obtains the means to become the Jewel Dopant (ジュエル・ドーパント, Jueru Dōpanto). Other than his ability to manipulate light and being impervious to most Maximum Drives, Uesugi uses his ability to turn Satoru into a diamond that he wears on his ring. He also forces Rui as his unwilling accomplice, making her seem to be the villain behind his crimes while appearing innocent as he turns many women into diamonds. However, Rui places a monkey wrench in the scheme by framing Detective Jinno and thus start a chain of events that exposes Uesugi and thwarts his plan to kill Rui off and leave town. By then, Philip manages to pinpoint the Dopant's one weakness and defeat him through the Bicker Charge Break Maximum Drive at the jewel's eye crack in his belt. With the Jewel Memory destroyed, Satoru and Uesegi's other victims are restored to normal. Makoto Uesugi is portrayed by Ryunosuke Kawai (河合 龍之介, Kawai Ryūnosuke).[40]
• Takashi Soma (相馬 卓, Sōma Takashi): A palm reader in Futo who Shroud gave the Old Memory to in a calculated plan to get rid of Shotaro. As the Old Dopant (オールド・ドーパント, Ōrudo Dōpanto), Soma took on the name of the Ager (ふけさせや, Fukesaseya), offering to age any person his customer hates for the right price, taking delight in his work. In his Dopant form, the Ager uses Old Creak (オールドクリーク, Ōrudo Kurīku), an ooze similar to the Terror Dopant's Terror Field, to age his target. By turning around, the Old Dopant can switch from the rust-colored form he uses the Old Creak in to a patina-colored faster form that is geared towards combat. Although Shroud states that only the power of Kamen Rider W CycloneAccel Xtreme can defeat the Old Dopant, Accel holds the Dopant for Double CycloneJoker Xtreme to make a direct hit while in his aging state. When the Old Dopant assumes his fighting mode, Accel uses the Machine Gun Slasher to defeat the Old Dopant. Takashi Soma is portrayed by Masakazu Azuhata (小豆畑 雅一, Azuhata Masakazu).[41]

Jun Kazu (加頭 順, Kazu Jun) is the white lab coat-wearing researcher for Foundation X, a valuable member of the organization who allows himself to be modified by the research of those he represents. He appears cold and emotionless, speaking in a flat monotone and when he sees others display emotions, he will drop whatever object he is holding in his hand. However, when roused to sufficient anger he releases his emotions like a torrent. Becoming a sponsor to the Museum and overseeing their investments, Kazu obtains a Gaia Driver and a Gold Memory. This Gold Memory, known as the Utopia Memory, allows him to become the seemingly omnipotent Utopia Dopant (ユートピア・ドーパント, Yūtopia Dōpanto), with reality-bending powers that result from the Utopia Memory's ability to grant its user's wishes, mainly used to repel attacks aimed at him, and absorb the emotions of living beings to further power itself. During the events of Kamen Rider Eternal, Kazu is revealed to have been Doctor Prospect's liaison to the Foundation and gain the psychic abilities of a Quark that enhances his Dopant abilities. At that time, he could use the Eternal Memory to become Kamen Rider Eternal. However, his incompatibility with the imperfect T1 GaiaMemory only enabled him to assume the weaker Red Flare (レッドフレア, Reddo Furea) mode. When Katsumi Daido manages to synch up with the Gaia Memory and negates the Utopia Memory, Kazu is killed by a perfected Kamen Rider Eternal with his body taken by the Foundation to be revived as a Necro-Over.

Arriving in Futo after his conversion, Kazu saves Saeko from her near death at the hands of the Smilodon Dopant out of love while offering the Foundation's support in her attempt to overthrow her father and Wakana. The briefcase he carries with him at all times contains the 26 T2 Gaia Memories; he eventually relinquishes this briefcase to Tabata to send it back to Foundation X's research facilities. After Ryubee's death, Kazu manages to save Wakana from the burning wreckage of the Sonozaki estate with the intent to use her in the Foundation's own version of the Gaia Impact: digitizing her into one of the Foundation's satellites in order to kill all life on Earth that is not compatible with Gaia Memories in an act of cleansing the human race's impurities. However, Wakana's comatose state forces Kazu to wait until her power resurfaces. In order to awaken her and reclaim Saeko, Kazu reveals himself to the Kamen Riders and assumes his Dopant form to overpower them. After discovering that Philip's emotions are tied to Wakana's powers as ClayDoll Xtreme, he decides to attack everyone close to him in order to initiate the Gaia Impact. After he is exposed as a Necro-Over, Kazu professes his love for Saeko and reluctantly kills her when she rebuffs and attacks him. Shotaro breaks into his lair and uses the Memory Gadgets to disable him and save Wakana, catching Kazu as the Utopia Dopant in a massive explosion as the lab goes up around him. He survives, however, and comes after them, battling Kamen Rider Double CycloneJokerXtreme. The duo manage to further weaken him by overloading him with Philip's final feelings before using the Double Prism Xtreme Maximum Drive to defeat the Utopia Dopant. Stumbling to his feet, Kazu asks if his own crime was to love and clicks the Utopia Memory one more time before it shatters and he dissolves away into nothingness.

During the events of OOO, Den-O, All Riders: Let's Go Kamen Riders, Utopia Dopant appears to be a member of Shocker in the altered timeline.

Jun Kazu is portrayed by Gong Teyu (コン・テユ, Kon Teyu).[42]

Tabata (田端) is a researcher from Foundation X who picks up the T2 Gaia Memories from Kazu to take them to the Foundation's headquarters in episode 44. However, as revealed in the opening of Kamen Rider W Forever: A to Z/The Gaia Memories of Fate, he is attacked en route in a helicopter to Foundation X's headquarters by Daido who takes the T2 Eternal Memory as he escapes death when Tabata activated the suitcase's self-destruct, killing himself as the helicopter explodes and the other T2 Gaia Memories spread throughout Futo.

Tabata is portrayed by Tsunekichi Takeoka (竹岡 常吉, Takeoka Tsunekichi).

Neon Ulsland (ネオン・ウルスランド, Neon Urusurando) is the woman in charge of Foundation X, usually researching Foundation X reports about unusual events or artifacts, such as NEVER or the O Medals, which are graded from A, B, C, D, or F. She is often seen with a stopwatch, as she is very strict when it comes to keeping schedules. She is shown to check her stopwatch frequently and doing strict allocations of time for matters, even interrupting others' talking and not sparing even a second more, should it affect her schedule. After Jun Kazu's defeat, she officially decides to end the foundation's Gaia Memory research.

Neon Ulsland is portrayed by Maria Theresa Gow (マリア・テレサ・ガウ, Maria Teresa Gau).[43]

Doctor Prospect (ドクター・プロスペクト, Dokutā Purosupekuto) was a Foundation X scientist who during the events of Kamen Rider Eternal was studying the use of psychic ability and created an army of psychic-powered soldiers known as Quarks (クオークス, Kuōkusu). To enforce his will upon the Quarks, Prospect can assume the form of the Eyes Dopant (アイズ・ドーパント, Aizu Dōpanto), able to detect an opponent's next move to counterattack, to brand the Quarks with an eye marking on their foreheads that would kill them should they try to escape. He also uses barrier known as Heaven's Horn (ヘブンズホーン, Hebunzu Hōn) to weed out weaker Quarks and ensure they die a peaceful death. In his fight with Katsumi Daido as Kamen Rider Eternal, he manages to kill all of the Quarks, including Mina as it seemed at the time, which enrages Daido and makes him go mad, killing Doctor Prospect by destroying his Gaia Memory and leaving him victim to its psychic killing effect.

Doctor Prospect is portrayed by Jyunichi Haruta (春田 純一, Haruta Jun'ichi).

Lloyd (ロイド, Roido) was one of Doctor Prospect's Quarks bodyguards before he was killed off by Gozo.

Lloyd is portrayed by Sho Tomita (富田 翔, Tomita Shō).

Shion (シオン) was one of Doctor Prospect's Quarks bodyguards before she was killed off by Kyosui.

Shion is portrayed by Sanae Hitomi (人見 早苗, Hitomi Sanae).

Katsumi Daido (大道 克己, Daidō Katsumi) is the leader of NEVER who fights with only a combat knife as his side arm. As revealed in The Beginning of N/Blood and Dream, Daido was born in Futo with a congenital heart defect. As a result, combined with a near-fatal car crash, his mother Maria uses her Necro-Over project research to revive her son as the first Necro-Over. Using bio-stimulants to enable him to properly age, Daido proves a superior fighter yet he and his mother turn against Foundation X after the organization shut down the Necro-Over project. Soon after, he recruits four people who recently died and were revived as Necro-Overs, forming a band of hired mercenaries. During one of their missions, Daido meets Mina and falls in love with her. During that time, Daido gains the experimental Eternal Memory and is able to transform into Kamen Rider Eternal (仮面ライダーエターナル, Kamen Raidā Etānaru). However, being forced to watch Mina seemingly die before his eyes turns Daido into a completely unfeeling monster as he kills Doctor Prospect, with the Eternal Memory getting damaged in the fight. Deciding to destroy Futo to wipe out the Museum, Daido serves as the main antagonist for W Forever and uses the T2 Eternal Memory to regain his Kamen Rider form. After his plans are thwarted by the combined efforts of Shotaro, Philip, and Maria, Daido utilizes all 26 T2 Gaia Memories to overpower Double, but is defeated and slain by CycloneJokerGoldXtreme. Long after their battle with the Museum ends, Shotaro and Philip learned the truth behind Daido's actions and pay their respects.

As Kamen Rider Eternal, Katsumi Daido uses the T2 Eternal Memory (T2エターナルメモリ, Tī Tsū Etānaru Memori) and a Lost Driver to assume the form of Blue Flare (ブルーフレア, Burū Furea) with the Eternal Robe (エターナルローブ, Etānaru Rōbu) cape. His Maximum Drive is called the Eternal Requiem (エターナルレクイエム, Etānaru Rekuiemu) which generates a power wave that neutralizes an enemy's Gaia Memory in sight, while the T2 version neutralizes all Gaia Memories with the exception of T2 Memories, a variation of this finisher also executes a Rider Kick to the target. Eternal is armed with the combat knife called the Eternal Edge (エターナルエッジ, Etānaru Ejji), which he uses in another Maximum Drive called the Bloody Hell Blade (ブラッディヘルブレイド, Buraddi Heru Bureido). Eternal can use other T2 Gaia Memories to access their powers like the T2 Unicorn Memory (T2ユニコーンメモリ, Tī Tsū Yunikōn Memori) to create an energy drill around his fist and the T2 Zone Memory (T2ゾーンメモリ, Tī Tsū Zōn Memori) to summon the other T2 Gaia Memories to him. In addition to the Maximum Slots on the Lost Driver and Eternal Edge, Eternal has a series of Gaia Memory Slots on combat belts around its chest, right arm, and left leg; with the Memory Slot in the Lost Driver, a total of 27. By filling all of these Memory Slots with the T2 Gaia Memories, Eternal is powered into his Strengthening Armament (強化武装, Kyōka Busō) mode, able to absorb the X-Bicker energy to produce the Eternal Wave (エターナルウェーブ, Etānaru Wēbu) green aura that he uses in his Neverending Hell (ネバーエンディングヘル, Nebāendingu Heru) Maximum Drive.[44][45] His catchphrase is "Now, enjoy your Hell" (さあ、地獄を楽しみな, Saa, jigoku o tanoshimina). Eternal's motifs is that of the letter E and a military commando.

At Anime Expo 2010, SOPHIA performed at a concert for the attendees. During the concert, they had Kamen Rider Eternal appear.[46]

Katsumi Daido is portrayed by Mitsuru Matsuoka (松岡 充, Matsuoka Mitsuru) of SOPHIA.[47] As a teenager, he is portrayed by Masaki Suda, who also portrayed the lead role of Philip.

Kyosui Izumi (泉 京水, Izumi Kyōsui) is a flamboyant gay man with sadomasochist quirks[48] who was originally a yakuza subordinate before he was betrayed and then fatally stabbed in the chest. He fell in love with Daido within seconds of his death and resurrecting, becoming his right-hand man while expressing any jealously against those who get close to Daido. Armed with a whip, Kyosui is an expert in grappling and can wrap himself around an opponent's body to snap them like twigs. Using the T2 Luna Memory to transform into the Luna Dopant (ルナ・ドーパント, Runa Dōpanto), he uses the power of illusions to produce the T2 Masquerade Dopants along with extending his whip-like arms to any distance. Though he manages to overpower Double, the Luna Dopant has a tougher time fighting Kamen Rider OOO, who destroys him with the Medajaribur's OOO Bash finisher.

Kyosui Izumi is portrayed by Genki Sudo (須藤 元気, Sudō Genki).[49]

Reika Hanehara (羽原 レイカ, Hanehara Reika) is a member of NEVER, formerly a serial criminal who was gunned down while attempting to escape from Alcatraz Prison to avoid the death penalty. She is turned into the newest of the Necro-Overs in the group. Coming to grips with her new existence, Reika hates the cold feeling of her undead body. Captured by Doctor Prospect's men, she helps Katsumi Daido in saving the Quarks before she is horrified to see the change in his personality after their deaths. Despite Daido's transition, Reika believed there will was some good left in him as she followed him to Futo, where she uses the T2 Heat Memory to transform into the Heat Dopant (ヒート・ドーパント, Hīto Dōpanto) with control over fire. She fights against Kamen Rider Joker but is defeated by his Rider Kick Maximum Drive, falling back to Futo Tower to beg Daido's help as her body begins to disintegrate. But she is rebuffed and has only enough time to curse Daido for his coldheartedness before vanishing in Shotaro's arms.

Reika Hanehara is portrayed by Minase Yashiro (八代 みなせ, Yashiro Minase).[44]

Gozo Domoto (堂本 剛三, Dōmoto Gōzō) is a muscular young man who died to protect a piece of land from developers, proficient with a staff while somewhat dimwitted. He uses the T2 Metal Memory to transform into the Metal Dopant (メタル・ドーパント, Metaru Dōpanto), armed with a rod with a hammer on one end and able to regenerate. He is willing to fight Shotaro and Philip as Double without the use of his memory. He is defeated by Shotaro as Kamen Rider Joker with the Rider Punch Maximum Drive in a failed cross counter.

Gozo Domoto is portrayed by Koji Nakamura (中村 浩二, Nakamura Kōji).[44]

Ken Ashihara (葦原 賢, Ashihara Ken) is a young man with knowledge of various firearms as he was once a military firearms expert before he was killed in a gunfight, leaving behind a family. As a member of NEVER, he is an expert marksman of the group armed with a machine gun and pistol and uses the T2 Trigger Memory to transform into the Trigger Dopant (トリガー・ドーパント, Torigā Dōpanto), armed with a large rifle attached to his right arm. He has a habit of proclaiming "Game start" when beginning combat. He fights Kamen Rider Accel on several occasions both in and out of Dopant form before being defeated by Accel Trial's Machine Gun Spike Maximum Drive.

Ken Ashihara is portrayed by Masayuki Deai (出合 正幸, Deai Masayuki).[44]

During the events of W Forever, The Luna Dopant uses his illusion powers to create henchmen for NEVER called T2 Masquerade Dopants (T2マスカレイド・ドーパント, Tī Tsū Masukareido Dōpanto).

Shiro Endo (遠藤 士郎, Endō Shirō) is a co-leader for EXE who possesses the Edge Memory (エッジメモリ, Ejji Memori). He pursues Yui's brother Akira to acquire the Ocean Memory. However, Shiro's posse are defeated and his Gaia Memory destroyed by Kamen Rider Joker before he could use it to transform into a Dopant.

Shiro Endo is portrayed by Shohei Nanba (南羽 翔平, Nanba Shōhei).

A nameless pet shop employee working under Santa-chan, who goes by the alias of "Energy" (エナジー, Enajī), is the true leader of EXE. It is only after the members of his group are arrested that Energy reveals himself as he attempts to kill Shotaro for meddling in his affairs. As the Energy Dopant (エナジー・ドーパント, Enajī Dōpanto), he is able to fire blasts of electromagnetic energy as well as use his left arm like a railgun. He is defeated when Philip returns and joins with Shotaro to become Kamen Rider Double CycloneJoker once more, destroying the Energy Memory through the Joker Extreme Maximum Drive.

The pet shop employee is portrayed by Tomu Suetaka (末高 斗夢, Suetaka Tomu).[50]

In addition to Shiro Endo and "Energy", there are three other unnamed members of EXE who fight Shotaro. One transforms into the Anomalocaris Dopant, another transforms into the Cockroach Dopant, and another is supposed to be given the Ocean Memory (オーシャンメモリ, Ōshan Memori) but never transforms into a Dopant as the Ocean Memory is destroyed before he can use it.

The EXE member who transforms into the Anomalocaris Dopant is portrayed by Ryusuke Ito (伊藤 竜翼, Itō Ryūsuke). The EXE member who transforms into the Cockroach Dopant is portrayed by Naofumi Kaneko (金子 直史, Kaneko Naofumi). The EXE member who is supposed to be given Ocean Memory is portrayed by Koki Matsumoto (松本 光希, Matsumoto Kōki).

"Master" (マスター, Masutā) is the owner of "Fumen" (風麺, Fūmen) ramen cart where citizens of Futo like to eat. His specialty is making ramen with large sized narutomaki. During the events of Hyper Battle DVD, he is attacked by the Oyakodon Dopant. However, after it is revealed to be Izo Aida, Master of the OmuriFu restaurant, he takes pity on him and hires him to work with him at his ramen cart. As a result, with Izo's help, Master devises a new Futo delicacy: "Futodon" (風都丼, Fūtodon).

In the webisode "The U is a Mystery!/Rondo" of the Net Movies, he becomes the UFO Dopant (UFO・ドーパント, Yūfō Dōpanto) while Jinno and Makura were experimenting the UFO Memory. He later travels into outer space as the UFO Dopant.

He also appeared in OOO, Den-O, All Riders: Let's Go Kamen Riders, begging his help from Shotaro and Philip, who transformed into Kamen Rider Double to fight against the Shocker combatants and the rest of Dopants.

The Master of Fumen is portrayed by Hiroshi Doki (道木 広志, Dōki Hiroshi), who is also the show's assistant line producer.

"Shroud" (シュラウド, Shuraudo) is a mysterious woman who is seeking revenge against Ryubee Sonozaki and the Museum and is Sokichi Narumi's childhood friend. In actuality, she is Fumine Sonozaki (園咲 文音, Sonozaki Fumine), wife of Ryubee and mother to Saeko, Wakana, and Raito (Philip). While a member of the Museum, she developed the Kamen Riders' Gaia Memories and the T2 Gaia Memories. After Raito died and was revived by the Gaia Memory, she wished to take him away from her insane husband and ended up being horrific scarred by the Terror Dopant's Terror Field. She left Ryubee and spends the next ten years plotting out her revenge, covering her face in bandages to obscure her disfigurement while referred by Ryubee refers to her as the embodiment of rage. Shroud initially intended of using Shinkuro Isaka to kill her husband by giving him the Weather Memory, but did not predict the doctor would test his newfound powers with a murderous streak. She later provided Sokichi Narumi with the needs to build the hangar beneath his agency's offices, as well as the Lost Driver and Skull Memory on the condition he would save Raito from the Museum. After Sokichi's death, Shroud would become Ryu Terui's benefactor after his family was murdered by Isaka as she considered him kindred spirit in the detective's need for revenge. But ultimately, while providing Philip with the means to create the Frog Pod and Denden Sensor, Shroud was conditioning Ryu to replace Shotaro as an ideal partner for Philip as Kamen Rider Double CycloneAccelXtreme.

But after her dealings with Isaka were revealed, Shroud eventually decides not to go through with her revenge while allowing the Kamen Riders to fight as they wish. She returns to the family estate one last time after Philip is taken in to allow Wakana to initiate the Gaia Impact, imparting her son with the knowledge that Shotaro is a wild card and only family he has left. Shroud's word inspire Philip to later save himself from the Gaia Memory, thwarting the Museum's plans. After the final battle with Foundation X, Shroud is seen in a flashback where she speaks with Wakana who seeks to initiate the Gaia Impact on her own. After telling her daughter the information she needs is in the Gaia Library, Shroud quietly passes away at Wakana's side. Shroud is last seen within the Gaia Library with the rest of her family, saying their goodbyes to the revived Philip and stating they will keep watch over him from as parts of the Earth.

Shroud has her own refined Gaia Memory called the Bomb Memory (ボムメモリ, Bomu Memori) which she uses in the Shroud Magnum (シュラウドマグナム, Shuraudo Magunamu) gun, a red-colored version of Double's Trigger Magnum. Its Maximum Drive shoots out a sphere of energy which splits into several smaller spheres that explode. Shroud also has several supernatural powers that do not have a basis in Gaia Memory use. She is able to summon up rings of fire that produce various objects, as well as appear out of thin air, and disappear just as easily. How she is able to do so is never explained in the series, although it is implied in the movie's Director's Cut Commentary that she is a Quark.

Shroud is voiced by Naoko Kouda (幸田 直子, Kōda Naoko), while Yūki Ono (小野 友紀, Ono Yūki) serves as the suit actor.

Lily Shirogane (リリィ白銀, Riryi Shirogane), real name Rie Shirogane (白銀 理恵, Shirogane Rie),[51] is a popular magician trying to follow in the footsteps of her grandfather Frank Shirogane (フランク白銀, Furanku Shirogane), real name Tasuku Shirogane (白銀 匡, Shirogane Tasuku).[51] To emulate his most famous trick, the disappearing lady, Lily is given the Invisible Memory by Dr. Isaka, turning her into the Invisible Dopant (インビジブル・ドーパント, Inbijiburu Dōpanto). However, Isaka has modified the Invisible Memory such that she does not turn into a monstrous Dopant and making it impossible to remove from her body. She initially goes to the Narumi Agency for help in finding the man who gave it to her under the pretense that she wishes to have it removed, but instead she wants to be able to control the invisibility. Isaka agrees, stabilizing the Gaia Memory, only because he knows it will eventually kill her and he will be able to take it from her after she dies, giving him the power of invisibility without the Dopant transformation. However, by killing her and using his Engine Blade as a defibrillator to quickly revive her, Accel removes the Invisible Memory and crushes it. Lily later returns in the events of Kamen Rider W Returns: Accel.

Lily Shirogane is portrayed by Nao Nagasawa (長澤 奈央, Nagasawa Nao).[52] As a child, Lily is portrayed by Sea Kumada (熊田 聖亜, Kumada Sea).

Nagi Shimamoto (島本 凪, Shimamoto Nagi) is a worker at the Futo Bird Sanctuary who became the unwilling subject of Isaka's experimentation with the powers of the Quetzalcoatlus Dopant (ケツァルコアトルス・ドーパント, Ketsarukoatorusu Dōpanto). After Isaka murdered her father, Nagi became the Quetzalcoatlus Memory's user with her fear towards Isaka and her compatibility to the Gaia Memory making it stronger. This was part of Isaka's plan to make increase the Gaia Memory's power for his use, using a copy of the Quetzalcoatlus Memory he created on a red-and-green macaw to further frighten Nagi by showing her the memory's power in the form of a giant Quetzalcoatlus Dopant and intending her to become one herself. But after Double CycloneJokerXtreme saves Nagi and destroys the copy Dopant, Accel Trial destroys the Quetzalcoatlus Memory so Nagi would be free of it.[53]

Nagi Shimamoto is portrayed by Miyuu Wagawa (和川 未優, Wagawa Miyū).

Maria S. Cranberry (マリア・S・クランベリー, Maria Esu Kuranberī), originally Maria Daido (大道 マリア, Daidō Maria), was a researcher for Foundation X, where she was known only as Professor Maria (プロフェッサー・マリア, Purofessā Maria), who used her research to save her son Katsumi Daido. After leaving the Foundation, Maria served as NEVER's support from adding new members to supplying weapons and vehicles. Arriving in Futo and using the T2 Cyclone Memory to transform into the wind manipulating Cyclone Dopant (サイクロン・ドーパント, Saikuron Dōpanto), Maria introduces herself as Maria S. Cranberry and as a member of the International Special Investigation Research Agency (国際特務調査機関, Kokusai Tokumu Chōsa Kikan) who was tracking NEVER, offering her services to Shotaro and Philip in order to get close to the latter so he can be used to power the X-Bicker with the T2 Gaia Memories. However, she gets second thoughts at the last minute and is killed by her son when she tries to stop him.

Maria S. Cranberry is portrayed by Aya Sugimoto (杉本 彩, Sugimoto Aya).

Melissa (メリッサ, Merissa) is a famous opera singer in Futo during the year 1999. She is later attacked by the Spider Dopant, which is then revealed to be Matsu who fell in love with her. She appears in the film Kamen Rider × Kamen Rider OOO & Double featuring Skull: Movie War Core, when the Pteranodon Yummy uses the Memory Memory on Akiko to reveal the events of Sokichi Narumi's past.

Melissa is portrayed by Hikaru Yamamoto, who also portrays Akiko Narumi.[4]

Kozo Yaguchi (矢口 孝三, Yaguchi Kōzō) is the manager of the Yaguchi Talent Agency that Melissa works for. Because of his seedy nature, he is a suspect for being the "Spider Man" that was plaguing Melissa. But in reality, Yaguchi was selling clients of his talent agency as guinea pigs for Gaia Memories before he was killed off by the Spider Bomb that Matsu implanted in Yaguchi's wife. He appears in the film Kamen Rider × Kamen Rider OOO & Double featuring Skull: Movie War Core when the Pteranodon Yummy uses the Memory Memory to reveal the events of Sokichi Narumi's past.

Kozo Yaguchi is portrayed by Kenta Satoi (佐戸井 けん太, Satoi Kenta).

Aoi Katsuragi (葛木 葵, Katsuragi Aoi) is the member of a pick-pocketing ring and the daughter of a thief. Prior to her appearance in Kamen Rider Accel, she was a witness to her father's murder by Hiroshi Sagami yet she could not remember his face. Due to the event, Aoi viewed any police officer to be against her until she meets Ryu when she is targeted by the Kamen Soldiers for unknowingly stealing the Gaia Memory Enhancing Adapter. As Ryu helps her get it to save her life, Aoi learns that she can change into a better person and turned herself in the end to start fresh.

Aoi Katsuragi is portrayed by Yukari Taki (滝 裕可里, Taki Yukari).

Mina (ミーナ, Mīna) is young woman who was a member of the Quarks months before NEVER arrived to Futo, one of the stronger specimens due to having psychokinesis, pyrokinesis, and psychometry. However, she turned against Doctor Prospect to help NEVER in freeing her fellow Quarks prior to Prospect using his Dopant powers to kill them. Though it turned out she survived, Mina's "death" caused Daido's descent into madness. In the events of Kamen Rider Eternal, after attempting to kill Double in order to avenge Daido, Mina reveals his story so Shotaro and Philip know the truth before she is hospitalized.

Mina is portrayed by Rin Takanashi (高梨 臨, Takanashi Rin).