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Icon-kiva.png This article is about a/an rider in Kamen Rider Kiva.

For the A.R World version, see Otoya Kurenai (A.R. World).

Otoya Kurenai (紅 音也 Kurenai Otoya) was a violinist, and the primary user of the original IXA system. He was notable for being the only human to transform into Kamen Rider Dark Kiva, although the strain from doing so cost him his life.


Otoya Kurenai is Wataru's father who battles the Fangire menace in 1986, his ideology that "All humans are music" his reason of fighting Fangires was to protect that music. Otoya was a ladies man who retires from being a professional violinist for reasons unknown. It was by accident that he interferes in Yuri Aso's mission and was eventually brought into their group as a result. Though normally a casanova, Otoya was vexed on anything marriage related, things always staying the same, and others getting in his way. He was the first to learn Jiro is actually a Wolfen, although no one believes him until later when Jiro threatened Yuri and reveals himself. He then becomes the second user of the Ixa System when Jiro was exposed, putting up a front of not suffering the suit's side effects.

He was also capable of reasoning with Fangires (and the other Demonic Races) who are not truly evil, an example being that he befriended Ōmura/Frog Fangire as he convinces him not to harm others. During his battle with the Fangire Race, Otoya falls in love with Maya, the original Queen of the Checkmate Four, resulting in the chain of events that led to him becoming the second Dark Kiva after forming a pact with Kivat-Bat the 2nd to take on the Fangires' King. Otoya, with help from a time-traveling Wataru, succeeds in destroying the King at the cost of being on the verge of death due to the strain of wielding Kiva's power. After assuring Wataru along with Maya before parting with him, Otoya would then pay final visits to his friends Yuri and the Arms Monsters (seemingly as a ghost) before finally dying in Maya's arms after playing her favorite song. He would leave behind the Bloody Rose, a violin that Otoya himself made with Maya's help, for Wataru.

However, in a strange turn of events in 2008, Otoya's spirit makes his appearance when he suddenly finds himself in Wataru's body due a fail attempt of a fortune teller to do the ritual for learning Kiva's identity. During that time, he recognized Megumi and Kivat as the children of those from his time and also starts building a new violin with Wataru unaware that his father was building it through him. He would appear to Wataru in spirit one final time, encouraging his son not to give up as he lives on through him. He was later mentioned by his future grandson Masao whom he was compared with Otoya. In the non-canon The Queen of the Castle in the Demon World net spin-off movies, Otoya is brought into the present and bought the Café mald'amour, renaming it the "Café Otoya D'amour" and attempting to remodel it.


Otoya was a strange and eccentric womanizing man. While on one hand he has ruined the lives of others through his antics, he has also helped others change their lives for the better. Some of these people he helped change like Omura, Jiro and Maya remember him fondly and respects him greatly, being known as a "great man".

Despite his oddness, Otoya is hinted to have a lot of life force with in him as he managed to live despite having his life energy drained by Castle Doran itself. He also managed to transform into Dark Kiva (also managing to transform into Ixa once then badly being beaten by the Bat Fangire between his second and third transformations) three times despite Maya stating that a normal human will die after becoming Dark Kiva even once.

Although he didn't appear to be the best role model, his son also respects him greatly and wished to meet him. When they do indeed meet, and Otoya learns that Wataru is his son, Otoya in his own way acted as a father for Wataru showing how much he can care for others. After finding out from Maya that King was holding baby Taiga hostage, he was willing to consider Taiga as his child and rescue him.

Even after sacrificing himself to stop the Bat Fangire, Otoya continues to support his son in spirit and encouraged him to not give up when Wataru was fighting the revived Bat Fangire.

"You bastard, what the hell do you think the music is?"
―Otoya to Hitomi Miyazawa after learning the purpose of her play[src]

Otoya has a great passion with music, the ultimate reason of why he never fear of monsters despite his first surprise. After the first encounter with Yuri and stole her weapon for a prank, he used it to throw a tantrum towards Hitomi, a fangire who used the music as a bait to prey. This also a sign on Otoya that despite he is a womanizer, it doesn't mean that he will forgive them for tainting the purpose of the music's existence



  • Master Violinist: Otoya was known for his prodigious violin skills.
  • Skilled Combatant: Otoya initially had little experience in fighting but soon learned more as he joined Yuri and the gang as he fought Fangires. His strength was fully shown when he, along with his son, managed to defeat the Bat Fangire despite its seemingly overwhelming powers.
  • Balance Proficiency: Like all Kurenai's, Otoya had the unique ability of being able to walk on the balls of his toes.
  • Indomitable Will: Otoya was known to be unusually robust as a human, always appearing to be full of life and easily excel at physical activities despite his inexperience in them. Otoya had an exceptionally high tolerance for pain, which allowed him to handle the strain put upon his body by the unstable IXA system and still fight effectively.Not only did he survive having more than half of his lifeforce sucked by Castle Doran, he proceeded to transform into Dark Kiva not long after & fought effectively with it--something which should have immediately cost him his life due to him being a full-blooded human. As the first human to not only have transformed into Dark Kiva but survived, he proceeded to transform into Dark Kiva for two more times despite the danger posed to his body, which was already falling apart due to his previously mentioned ordeals, and survived intact on both occasions still. He only finally died having succumbed to the effects of using Dark Kiva's powers excessively, but still with enough time for him to realize his end was near and say his farewells to his friends.


Save Mode

Kamen Rider Ixa

"Fist On!"
―Transformation announcement[src]
  • Rider Statistics:
    • Rider Height: 218 cm
    • Rider Weight: 160 kg
  • Ability Parameters:[1]
    • Punching Power: 4.2 t
    • Kicking Power: 1.8 t
    • Maximum Jump Height: 18 m
    • Maximum Running Speed: 100 m per 9.6 seconds

The IXA system, an acronym for Intercept X Attacker, is a Rider System developed for fighting Fangire. Otoya uses the Prototype Version of the Ixa System, which only has access to Save Mode (セーブモード Sēbu Mōdo).

In 1986, the Ixa System was still in development. There were several technical problems such as the armor shooting out steam, a constant beeping, and the Ixa Knuckle producing sparks when activating a Fuestle. In addition, Ixa only has access to the Knuckle Fuestle. In contrast to the 2008 versions, the Ixa Knuckle had a deeper tone of voice and uses a bronze projection for the Ixa System's transformation. The Ixa Prototype Version exhausts a qualified person's body considerably even if they are not human, as the System still managed to harm both Jiro and Rook. Prolonged usage of the IXA system caused Otoya to develop temporary amnesia.

By inserting the Knuckle Fuestle into the Ixa Belt and pressing the Ixa Knuckle, Ixa can perform the Broken Fang (ブロウクン・ファング Burōkun Fangu) finisher.

Kamen Rider Ixa is composed of the following parts:

  • Ixa Met (イクサメット Ikusa Metto) - The helmet. It is composed of Ixa Platinum (イクサプラチナ Ikusa Purachina), a diamond-hard material made exclusively for Kamen Rider Ixa. Ixa Platinum was developed from 8AL-7V Titanium (8AL‐7Vチタニウム 8AL‐7V Chitaniumu), one of the strongest current alloys on Earth, and is considered as the material that next-generation weapons and armor would be made out of. The metal was obtained via special routes. All information is transferred to the user within via internal pads that mount through electrical contact.
    • Hunting Glass (ハンティング・グラス Hantingu Gurasu) - The eyes. They are ultra-wide lens that possess a 180° field of view in front, and video information captured is transmitted to the wearer inside via an in-helmet terminal. It also contains a type of night vision scope function that can even see in darkness with zero visibility, and a Super X-Ray (スーパーXレイ Sūpā X Rei) function that allows Ixa to see through a 5 meter thick iron plate. The Hunting Glass can record images via a digital camera lens and save it onto a built-in disk.
    • Access Signal (アクセスシグナル Akusesu Shigunaru) - A blue light on the forehead. It blinks when a computer within the Ixa System accesses internal disks.
    • Cross Shield (クロスシールド Kurosu Shīrudo) - The golden cross-like visor. In Save Mode, it closes down to cover the Hunting Glass. Immediately after transformation, the Cross Shield closes to prevent the suit from self-destructing and to protect the face where high precision instruments are located. In Burst Mode, all energy is concentrated in one point (the weapons) to enable devastating special moves. Since Burst Mode not only consumes considerable energy but also puts a high load on the suit and the built-in computer, continuous operation in Burst Mode for more than 30 minutes is highly dangerous.
    • GPS Bit (GPSビット GPS Bitto) - The blue tips on top of the Cross Shield. They are antennae that lets Ixa know the location of an optical beacon as if they were using a satellite.
    • Poisona Filter (ポワゾナフィルター Powazona Firutā) - The white section between the eyes. It is a device that decomposes and purifies all toxins to supply safe air to the wearer.
    • Masker Regulator (マスカーレギュレーター Masukā Regyurētā) - The mouthplate. An ultra-small oxygen cylinder in installed, enabling approximately 360 minutes (6 hours) of underwater activity and in low oxygen conditions.
  • Sol Mirror (ソルミラー Soru Mirā) - Chest-mounted power unit. It is a next-generation power engine that increases stored power by hundreds of times. This energy converted by the Ixa Engine (イクサエンジン Ikusa Enjin), a black boxed device, transcends human intelligence. In order to efficiently cool down the heat, which is produced as a by-product of the tremendous energy, an opening around the central mirror is used as a heat dissipation block. Small indicator lights arranged around the centre in a cross-like pattern indicate the flow of energy. The indicator placed in the middle top is red, and the indicators to the left and right are green, and are said to be the ideal indicators of energy.
  • Delta Earth (デルタアース Deruta Āsu) - Aerial discharge-type grounding systems provided on the shoulders, hips and back. Discharges high voltage that flows excessively through the suit into the air, reducing the burden on the body.
  • Sol Flasher (ソルフラッシャー Soru Furasshā) - The light bars on the shoulders. Energy can be concentrated here to be used as a flash grenade. The amount of light is 3 million candela. The intensity of the flash can lead to blindness in ordinary people with a single shot, making it even more effective against Fangires, who dislike light. Therefore, it can be said that this is specifically anti-Fangire equipment. Additionally, during normal operation, it plays the role of a condition signal that flashes red when a yelow light pops up, a malfunction occurs, or when battery level is significantly reduced.
  • Black Armor Suit (ブラックアーマースーツ Burakku Āmā Sūtsu) - The bodysuit. It is an inner suit that wraps around the wearer and protcts them from external impact. It is made from Carbotech Linen (カーボテックリネン Kābotekku Rinen), one of the strongest synthetic fibres ever made. Theoretically, it can withstand temperatures of 2000°C, and boasts an intense tear strength of 200t.
  • USM (Ultimate Servo Motor System) (USM(ウルティメットサーボモーターシステム) USM (Urutimetto Sābo Mōtā Shisutemu)) - The servomechanisms. It is an ultra-compact high-power motor that produces power equivalent to a 5000cc-class industrial combustion engine. By connecting both upper and lower arms with a strong ultra-thin inner frame, and assisting the arm with artificial muscle fibre (マッスルファイバー massuru faibā) which operates via electrical signals, the user is given tremendous extraordinary strength. A similar system is installed within the legs.
  • Ixa Armor (イクサアーマー Ikusa Āmā) - The arm armor. Has a hardness of 8.522. It is made of Ixa Platinum. It also contains sterling silver (スターリングシルバー sutāringu shirubā), a material that dislikes Fangires, and 87 Titanium (87チタン 87 chitan).
  • Hunting Grabs (ハンティング・グラブ Hantingu Gurabu) - The hands. An ultra-thin inner frame is built into the USMand the fingertips, providing 20 times the grip strength of ordinary people. Electrical contacts are built into the palm to connect to the Ixa Knuckle.
  • Emergency Battery (エマージェンシーバッテリー Emājenshī Batterī) - Spare power packs contained in the legs for when Ixa runs out of power. The power transition is automatic and can always be carried as a backup power source. The main power unit can operate up to 12 hours while an Emergency Battery can operate up to 6 hours.
  • Power Knee Unit (パワーニーユニット Pawā Nī Yunitto) - The knees. It incorporates an assisted artificial knee joint with USM, creating superhuman leg strength. Since a large amount of electricity flows through it, a bunch of Delta Earths are provided to efficiently discharge excess voltage to reduce burden.
  • Super Absorber (スーパーアブソーバ Sūpā Abusōba) - The ankles. The ankles are wrapped in multiple layers of muscle fibre, providing tremendous leg strength. In order to reduce burden to the legs, air shock absorbers (エアショックアブソーバ ea shokku abusōba) are incorporated on both sides of the ankles and on the soles of the feet.

Appearances: Kiva Episode 13-14, 16, 25, 27-31, 41-46, 48 (briefly as a spirit), King of the Castle in the Demon World

Dark Kiva

Kamen Rider Dark Kiva

―Dark Kivat's transformation announcement[src]

Rider Statistics:

  • Rider Height: 205 cm[2]
  • Rider Weight: 112 kg[2]
  • Ability perimeters
    • Punching power: 20 t[2]
    • Usual kicking power: 35 t[2]
    • Maximum jump height: 250 m[2]
    • Maximum running speed: 100 m. per 1.2 sec[2]

With Kivat-Bat the 2nd, Otoya became Dark Kiva, the only human ever to do. Dark Kiva only appears to have one form, similar to that of Kiva Emperor Form However, Dark Kiva does not require the use of a being such as Tatsulot to achieve this form, and has no chains on his body as Kiva needs to control his power. Like King, Otoya has access to a unlimited potential of power that is hindered within his successor such as telekinesis and the use of the Kiva insignia as a weapon.

As Maya would later explain, the human body is unable to handle the strain of becoming Kiva: a single usage is fatal to most humans. Otoya was able to become Dark Kiva a total of three times before finally dying due to the strain it put on his body. Shima also mentioned this when Wataru revealed his heritage to him.

In search of a power stronger than the Saga armor, the Fangire created a new armor meant for the second king. The armor is also known in dialogue as the "Kiva of Darkness" (闇のキバ Yami no Kiba), and can reach its limits by accessing the wearer's natural abilities, but it has the drawback of making the wearer lose control. The first King, now equipped with the Dark Kiva armor used the Wake Up III finisher "King's World End" during the fight against the Legendorgas. Due to the huge loss of Fangire life after the finisher was used, Knight and Pawn sealed off the use of the finishing attack.[3]

Kamen Rider Dark Kiva has the following parts:

  • King's Persona (キングス・ペルソナ Kingusu Perusona) - Dark Kiva's helmet. The bat-like wings on the head are called "Zenon Stabilizers", and spreads the stress on the user's brain by maximizing the demonic power of the user and armor.
  • Darkness Breast (ダークネスブレスト Dākunesu Buresuto) - A depressant called Darkness Tar is applied to the armor to control the demonic power which is amplified by the 3 Demon Emperor Stones to prevent self-destruction. The silver stripe in the center is called the Satan's Vessel (サタンベッセル Satan Besseru). It is an energy conduit that is connected to Kivat-Bat II to control the demonic power.
  • Demon Emperor Stone (魔皇石 Ma Ō Ishi) - Like Kiva Emperor Form, the stones control the air, water, and Earth, and amplifies the strength of the user by ten. The purity is higher than Emperor Form's 3 stones and has stronger amplification powers.
  • Darkness Veil (ダークネスベール Dākunesu Bēru) - The cape. It can neutralize all physical attacks in the world. By swinging the cape, Dark Kiva can generate a blade of darkness to penetrate enemy defenses.
  • Satan Mail (サタンメイル Satan Meiru) - The undersuit made of GaoraDoran leather. The material is rare, and it is made using the finest quality 1200-year-old Doran leather and boasts 3 times the defense of Kiva's armor.
  • Bloody Shoulder (ブラッディショルダー Buraddi Shorudā) - The shoulder armor made of polished Bloody Stone, has a blade that is sharp enough to cut like a razor with just a touch. It functions as armor and a powerful weapon in close combat.
  • Bloody Armor (ブラッディアーマー Buraddi Āmā) - The bright crimson armor made of Bloody Stone. It is said it is not possible to refine it further, it stores demonic power and combines the power with the user.
  • Stabilize Shadow (スタビライズシャドー Sutabiraizu Shadō) - The black lines on the Bloody Armor. They are restraint bands made of Darkness Tar with the purpose of cooling down the demonic power to protect the user from being overpowered and self-destructing as a result.

Kamen Rider Dark Kiva has the following finishers:

  • Darkness Hell Crash (ダークネスヘルクラッシュ Dākunesu Heru Kurasshu): Referred to by Kivat-Bat the 2nd as "Wake Up One," the Darkness Hell Crash is a punch with the force of 65t. When performed, day turns into night with blood red fog. Dark Kiva then does a flying punch with his right arm.
  • King's Burst End (キングスバーストエンド Kingusu Bāsuto Endo): Referred to by Kivat-Bat the 2nd as "Wake Up Two," the King's Burst End is a Darkness Moon Break-style kick with the force of 180t and green energy blades.
  • King's World End (キングスワールドエンド Kingusu Wārudo Endo): Referred to by Kivat-Bat the 2nd as "Wake Up Three," a self-destruct attack with an unknown amount of power. It was not used in the series.

Appearances: Kiva Episode 45-46



Behind the Scenes


Otoya Kurenai is portrayed by Kouhei Takeda (武田 航平 Takeda Kōhei), who would later go on to play Kazumi Sawatari in Kamen Rider Build. As a child, he is portrayed by Ayumu Maruyama (丸山 歩夢 Maruyama Ayumu). As Kamen Rider Ixa, his suit actor is Jiro Okamoto (岡元 次郎 Okamoto Jirō), whereas the suit actor for Kamen Rider Dark Kiva is Eitoku (永徳 Eitoku).


  • Even though Otoya and Wataru have met through time travel, Otoya didn't recognize his own son when he entered his body as a ghost thus creating a time paradox.
  • Otoya is similar to Gai Yuki (Black Condor)Icon-crosswiki.png from Choujin Sentai JetmanIcon-crosswiki.png, especially in their womanizing ways. Both fell in love with a fellow heroine of their time - Yuri to Otoya and Kaori (White Swan)Icon-crosswiki.png to Gai.
  • According to Kouhei Takeda in his blog, Otoya's pose when transforming into Ixa is a homage to Takeshi Hongo's transformation pose as Kamen Rider 1.[4]

Kazumi Sawatari Dogtag.jpg

  • Takeda's future role as Kazumi Sawatari contains a reference to his role as Otoya in the form of a dogtag pun: 9 ( Ku), 0 ( Re), 7 ( Na), 1 ( I) , 0 ( O) 10 ( To), 8 ( Ya).
    • In another sheer coincidence, both transform into Riders with an upgraded form that will put them into mortal danger - Dark Kiva and Grease Blizzard, respectively. This is further enforced by how the risk posed is from the nature of the transformation(using Kivat II as a pure human and the Hazard-Level increasing effect of the Grease Blizzard Knuckle), and not the taken form.



Icon-kiva.png Kamen Rider Kiva
Kamen Riders
Wataru Kurenai - Keisuke Nago - Taiga Nobori - Kengo Eritate - Otoya Kurenai - Takato Shiramine - Takashi Sugimura - Masao Kurenai
Kivat-Bat the 3rd - Kivat-Bat the 2nd - Kivat-Bat the 4th - Rey Kivat - Arc Kivat
Sentient Allies
Demon Imperial Dragon Tatsulot - Castle Doran - Shoodoran - Zanvat Sword - Machine Kivaa
The Arms Monsters: Jiro - Ramon - Riki
Kivat Belt - Ixa Belt - Ixa Knuckle - Dark Kivat Belt - Rey Kivat Belt - Arc Kivat Belt - Fuestles - Ixa Calibur - Ixariser - Powerd Ixer - Ixalion - Jacorder - Gigantic Claw - Arc Trident
The Wonderful Blue Sky Organization
2008: Mamoru Shima - Keisuke Nago - Kengo Eritate - Megumi Aso
1986: Otoya Kurenai - Yuri Aso
The Fangires
The Checkmate Four:
1986: Bishop - Rook - Queen I - King I
2008: Bishop - Rook - King II - Queen II
Pawns: Horse Fangire - Octopus Fangire - Moth Fangire - Sheep Fangire - Ryo Itoya - Prawn Fangire - Frog Fangire - Earwig Fangire - Rhinoceros Fangire - Seastar Fangire - Ladybug Fangire - Chameleon Fangire - Grizzly Fangire - Shark Fangire - Crab Fangire - Cicada Fangire - Warthog Fangire - Tortoise Fangire - Moose Fangire - Horsefly Fangire - Rat Fangire - Mantis Fangire - Seamoon Fangire - Sungazer Fangire - Silkmoth Fangire - Polar Bear Fangire
Takato Shiramine - Takashi Sugimura
Mummy Legendorga - Medusa Legendorga - Mandrake Legendorga - Gargoyle Legendorga - Antlion Legendorga