Takeshi Asakura
Asakura Ex-Aid
Used by
Tengen Toppa Lazengann
Kamen Rider KickHopper, Dai-Shocker, his contract monsters
190 (Normally)
Kamen Riders
Kamen Riders

Takeshi Asakura (浅倉 威 Asakura Takeshi) is Kamen Rider Ouja (仮面ライダー王蛇 Kamen Raidā Ōja, lit. "King Snake"), a Rider in the Kamen Rider Series Kamen Rider Ryuki. He is the sixth of the 13 Kamen Riders the story revolves around and serves as one of the main villains in the series.


Asakura was born in 1977. At age 13, he murdered his entire family in a fire, though his younger brother survived. Since, Asakura developed a reputation as a sadistic felon with a love to fight, maim and otherwise destroy anything in his random fits of rage. As a result of his sadistic nature, prior to becoming a Rider, Asakura was personally responsible for both ending the piano career of Tezuka's friend Yuichi Saito and murdering the older sister of Miho Kirishima. Eventually, his arrogant personality results with his defense attorney, Shuichi Kitaoka refusing to represent him and left him to rot in jail. Because he was in prison and could not feed his destructive nature, Takeshi gladly accepted Kanzaki's offer to join the Rider War and forms a pact with Venosnaker, using his newfound powers as Ouja in its many forms to break out of jail, avoid the law, and get his revenge on Kitaoka.

Ouja fought only to fight and was the first Rider to actually kill other Riders, killing Kamen Rider Gai and Kamen Rider Raia and taking their Contract Monster afterwards. Ouja also destroyed Kamen Rider Imperer's deck, causing him to die in the Mirror World. While the other Riders had a desire that would be granted if they won the Rider War, Asakura was simply having fun, and said that if he won, he would wish for the Rider War to start over so he could keep enjoying himself.

Ren helped Asakura fake his death once so he can fight in the Rider War without police interference. But when he was publicly revealed to be alive, Asakura was soon later captured, going in and out of jail for several instances. In one such case, he uses Metalgelas while in a police van to dispose of his police captors before escaping into the Mirror World. After a fight with Kamen Rider Survive Ryuki and Kamen Rider Tiger, he had been seriously injured and handed back to the authorities once again by Shinji. Soon he escaped again, with aid of his lawyer at that time whom he had knocked out and switched clothes with the lawyer to escape.

In the process of learning of Kitaoka's identity as a Rider, Asakura attempted to lure him by staging a hostage situation to get Kitaoka. Asakura had Venosnaker kidnap Goro Yura so Ouja can pressure Zolda into bringing Knight, Ryuki and Raia to a specific meeting place. However, Goro escapes by picking the lock of the handcuffs. Though he lost to Zolda, Ouja survived and senselessly killed Kamen Rider Gai in the process.

Upon learning of Kitaoka's identity as a Rider, he formed a personal grudge against him that manifested in many attempts to harm Kitaoka. The two would fight many times throughout the series. Miyuki Tezuka (Kamen Rider Raia) also held a personal grudge against Asakura for ending the piano career of his friend, Yuichi Saito.

During the series, he came under fire from his three monsters when they were hungry for life energy. They came close to devouring Asakura if not for his strong determination. After hunting down three Mirror Monsters, Ouja was able to feed his contract monsters. Kamen Rider Knight and Zolda tried to prevent his monsters from feeding so that they would turn on him and remove Asakura from the Rider War. but Kamen Rider Ryuki intervened and allowed the monsters to feed because Asakura had actually saved a small girl from the three monsters they hunted.

At the end of the series he finally has his showdown with Zolda. Ouja, using his "Doomsday" Final Vent, destroys Magnugiga before fatally injuring Zolda. Though happy with his victory, Ouja finds out seconds later that "Zolda" was actually Goro, as Kitaoka gave him his vent deck prior to succumbing to his cancer during the fight. Just as he returned to the real world in utter disarray of being denied the right to kill the man he hated the most, Asakura finds himself surrounded by the authorities in the warehouse he was in with snipers covering them. Defiant to the end, Asakura grabs a metal rod and runs at the cops screaming as they gun him down, brought to justice at last.

But because Kanzaki restored time to its proper course after Yui's death, Asakura was given a second chance in life with no memory of being a Rider and keeping a low profile, but still having a rude personality, as he was kicking Shinji's bike because it was in the way.

Ouja is later summoned in the World of Hibiki by Kiva-la, wielding a kanabō which he uses to summon a Bakegani from the mountain side after knocking Kiva-la aside.

Asakura later appears to fight the organization, Dai-Shocker. However due to his sadistic nature he sides with Dai-Shocker along with KickHopper (Yaguruma). He attempts to stop Diend and Natsumi only for Diend to summon Gai, Raia, and PunchHopper to fight him and Yaguruma. He fought Gai and Raia, the two riders he killed in the series. The outcome of the fight is unknown.

Asakura was later revived along with the Beast Rider Squad as part of Foundation X's scheme in researching the Rider Gashats. He attacks Hiiro Kagami's nurse assistants, Mizuki and Satsuki, as well as Emu Hojo. Asakura as Ouja would later be defeated by Brave's Level 4 form, leading to Asakura fading away once again.

Later, he would appear to be revived, leading him to first team up with FlamingoMask against a group of Mechanical Gangsters, before later turning on FlamingoMask. During their fight, Ouja was able to overpower FlamingoMask, but ended up leaving out of boredom, while FlamingoMask was left alone so that he could heal his own wounds.

Some time after this Asakura would appear to the man who was known as Kamen Rider Garren, or Sakuya Tachibana, looking for a fight. Overpowering the other Rider, Ouja used his Advent to trick Garren into trying to use his Gemini Rouze card, only to steal it using his Steal Vent. After stealing Garren's Gemini Card, Ouja was able to use it in his visor, creating a duplicate of himself, which would be defeated by Garren's finisher. While Garren attacked his clone, Ouja used his Final Vent to hit Garren while he was distracted, planning to beat him to death, until deciding not to, due to Garren entertaining him. With that fight finished, Asakura left with Venosnaker, and his Gemini clone's corpse, as well as most of Tachibana's rouze cards. With that, he disappeared back into Mirror World.

Some time later, he was confronted by Ryuki, who demanded he give back the Rouze cards, in exchange for his Survive Rekka card. Seizing the moment, Ouja attacked Ryuki, who defended himself with Survive to show him the power it holds. Seeing this Ouja agreed, on the condition that he and Ryuki would fight when they were the last two Riders left. Agreeing to the deal, Ryuki handed over the Survive card, and took Garren's Rouze cards back.

A couple hours later, Asakura was attacked by an old rival, Kamen Rider Femme, who had come to avenge her sister's death. Easily countering her attacks, Ouja was able to overpower her, and would have beaten her to death, had it not been for the timely arrival of Zolda, who used his End of the World Final Vent to trap Asakura under a fallen building, before leaving with the beaten and bruised Femme. Ouja was able to survive due to his mirror monster taking more of the damage, but promised to kill Zolda later, as well as Femme.

After surviving his previous battle, Asakura was able to locate an old enemy of his, Masashi Sudo, who had recently forged evidence on Femme's sister's murder case, which implicated Asakura, and was in fact Kamen Rider Scissors. Transforming, Ouja and Venosnaker attacked Scissors and his Mirror Monster, Volcancer. During the battle, Ouja was able to overpower Scissors, with the two trading blows for a while, while their Mirror Monster fought. Once Scissors activated his Final Vent, Ouja saw an opportunity and active his own, using his Bicycle Kicks to knock Scissors into Volcancer's claws, impaling him.

With him being impaled, Ouja approached the now untransformed, yet alive, Masashi, and pulled him from his monster's claws, before beating him to death with glee. Finally, with no one left to implicate him in the murder charge, Asakura was a free man again. Using the opportunity, he was able to take Scissors' cards and added them to his own deck, as well as forming a contract with Volcancer, before heading off.

A few months, Asakura resurfaced alongside Odin to fight Tiger and the two Alternatives, who had discovered the Core Mirror, and were preparing to destroy it. Overwhelming the two Riders, Ouja proceeded to beat Alternative Zero half to death, before allowing Volcancer to devour the defeated Rider, leaving behind his destroyed deck. Watching as Odin overwhelmed the remaining Alternative and Tiger, Ouja saw an opportunity, and initialized his Survive, before using his Final Vent on Odin, defeating him. Before the Odin deck disappeared, Ouja was able to make a contract with Odin's contract Monster, acquiring Odin's deck and removing him from the Rider War.

Turning to face the remaining Alternative and Tiger, Ouja grew angry when he saw that the two had retreated.


Asakura is a violent and sadistic man, finding joy in fighting, maiming, killing, or otherwise destroying anything in his random fits of rage. He has no sympathy or remorse for his actions, and will attack anyone simply because he was "vexed".


  • Rider Height: 200cm
  • Rider Weight: 98kg
  • Ability Perimeters:
    • Punching Power: 12.5 tons
    • Kicking Power: 20 tons
    • Max Jump Height: 40m
    • Maximum Running Speed: 100m/5s

This is Ouja's standard form that he had throughout most of the series, obtained once he forms his contract with Venosnaker. A melee-based Rider, Ouja's fighting style helped him in his victories more often than any of his Advent cards, using the Veno Visor (ベノバイザー Beno Baizā) scepter to conjure his spiral-bladed Veno Saber. His Final Vent is Veno Crash (ベノクラッシュ Beno Kurasshu), running at an opponent with Venosnaker slithering behind before raising its head up as its master jumps back towards it and the Mirror Monster launches him so he can deliver a rapid bicycle kick at the target. Once he defeated Gai and Raia, he had access to both their contract monsters and their Advent cards, becoming an even more dangerous force to be reckoned with the Unite Vent to create Genocider so the Final Vent Doomsday is used, with Ouja corkscrew kicking his opponent into a vortex that materialized on Genocider's torso.

Survive Form
  • Rider Height: 198cm
  • Rider Weight: 97kg
  • Ability Perimeters:
    • Punching Power: 17.5 tons
    • Kicking Power: 27.5 tons
    • Maximum Jump Height: 60m
    • Maximum running speed: 100m/3s

Kamen Rider Ouja Survive (仮面ライダー王蛇サバイブ Kamen Raidā Ōja Sabaibu) is Ouja's ultimate form. This form is acquired when Ouja stole the Survive Shippu card from Kamen Rider Knight, becoming more powerful than his other forms. His contract monster Venosnaker, is also able to change into a more powerful version, Venoviper (ベノバイパー Benobaipā), and combine it with other stolen contract monsters to form Genosurviver (ジェノサバイバー Jenosabaibā).

Advent Cards


OujaAdvent SwordVentOuja StealVent VenoVent UniteVent SurviveRekka CopyVent ConfineVent OujaVolcancer OujaPincer OujaShell OujaScissors OujaGoldPhoenix OujaSwordVent2 Genocider


OujaEvildiver DiverVent OujaSwingVent OujaMetalgelas MetalVent OujaMetalHorn SurviveShippu

Contract Monsters

  • Height: 310 cm (10.1706 feet)
  • Weight: 490 kg (1080.27 pounds)


  • Maximum Travelling Speed: 500km per hour

Obtained through the Unite Vent Advent Card after Ouja used two spare Contract Cards to Contract the stray Monsters of defeated Riders, Genocider is a combination of Kamen Rider Raia's Evildiver, Kamen Rider Gai's Metalgelas, and Kamen Rider Ouja's Venosnaker. As such, it is an amalgamation of all three: the body of Metalgelas, Venosnaker attached onto its back as a long neck and tail, Metalgelas' face and horn on Venosnaker's head, and Evildiver strapped to the back of the creature, the front edges of its wings sprung up to form an 'X' shape.

Later, Ouja was able to create a complete version of this creature without requiring all three of his contract monsters by using a Copy Vent card, leaving a completed version of Genocider alongside his other monsters before Raia and Gai were revived by Kanzaki, causing them to return to their former masters.

  • Doomsday (Final Vent): A vortex opens up on Genocider's chest, with Ouja corkscrew-kicking his opponent into it.

  • Animal Basis: Cobra
  • Length: 625cm
  • Weight: 190kg


  • Maximum Travelling Speed: 500km per hour

Venosnaker resembles a giant mechanical cobra. It's able to spit out a thick venom from its mouth at the opponent that melts anything it touches. This monster was also a direct counterpart to Ouja as seen having a vicious and animalistic personality and even attempted to attack its master out of hunger.

Venosnaker was already contracted to Asakura's Card Deck before he became Kamen Rider Ouja. He played a pivotal role in the deaths of both Jun & Tezuka. Because Venosnaker is as tall as Dragreder, they've both fought against each other before on multiple occassions.

After a certain period of time, Venosnaker, who hadn't been fed by Asakura in a while, started to act violently towards him in breach of contract. However, Asakura was safely able to feed Venosnaker before it completely killed him.

Near the end of the Rider War, Venosnaker assisted in killing Goro Yura, who had taken up the Zolda deck from Shuichi Kitaoka.

  • Veno Crash (Final Vent): Venosnaker launches Ouja into the air, after which the latter performs a bicycle kick to the opponent.


  • His Rider name, Ouja, could also literally meant "King Evil" (王邪 Ōja), as he is the long standing evil Kamen Rider in this series.