This article is about a/an rider in the film Kamen Rider ZO.
Kamen Rider ZO
Masaru Aso
Gender: Male
Series: Kamen Rider ZO
Motif: Grasshopper
Rider Type: Protagonist
Homeworld: Earth (Main Timeline Continuity)
First Appearance: Kamen Rider ZO
Last Appearance: Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai
Number of Episode
6 (Movie)
Actor: Kou Domon
Kamen Rider ZO

Masaru Aso (麻生 勝 Asō Masaru?) is Kamen Rider ZO (仮面ライダーZO Kamen Raidā Zetto Ō?), the main protagonist in the Japanese tokusatsu movie Kamen Rider ZO.


Masaru was originally an assistant to Doctor Mochizuki until the doctor conducted experiments on him. Horrified at being made into a grasshopper-like cyborg, Masaru went into hiding in the mountains for two years until he awoke with an unconscious urge to protect Hiroshi. Though he hated Mochizuki, Masaru eventually forgave him before learning the man was telepathically communicating with him.

Kamen Rider WorldEdit

ZO and J, with Berry

ZO and J, with Berry.

Later, ZO teamed up with Kamen Rider J. The two riders fought a gang of five revived monsters led by Shadow Moon: Sai Mutant, Cyborg Soldier Lv. 2, Agito, Garai, and Zu. Berry witnessed Shadow Moon's plot and is attacked by the mutants. Masato and his sister Ayumi stumble onto an injured Berry by chance and are chased by the revived mutant army as a result.

However, they are saved by the sudden arrival of Kamen Rider ZO on his ZO Bringer motorcycle, who thwarts off the monsters into a nearby abandoned warehouse. ZO is suddenly assisted by Kamen Rider J, who arrives into the warehouse on his J Crosser bike. The five mutants are defeated by the combined forces of the new Double Riders. The two are then challenged by Shadow Moon, who enlarges himself into giant proportions. J grows into giant size as well and fights off Shadow Moon by himself. Shadow Moon is defeated and peace returns to the day. Kamen Rider World

Let's Go Kamen RidersEdit

ZO (Let's Go Kamen Riders)

ZO as seen in Let's Go Kamen Riders.

A mishap caused by the Greeed Ankh unintentionally altered the timeline which enabled Shocker to utilize a Cell Medal to create the Shocker Greeed which defeated the Double Riders and seemingly erased the legacy of the Kamen Riders from history. In 2011, after Kamen Rider New Den-O's attempt to repair the damage, he along with Kamen Rider OOO and M-Ankh awaited execution. However, it was revealed the Double Riders had their brainwashing removed by a Shocker scientist.

The Double Riders joined with New Den-O and OOO to fight Shocker's forces, but were eventually defeated. When the order was given to kill everyone, V3 suddenly appeared, asserting that there were more than four riders. V3 was soon followed by all the other revived riders that came after him, including ZO, as even though Rider history was changed, the people's memories haven't changed.

After the riders were united, they faced off against Shocker's Great Leader. Later, when joined by a force of extra riders, ZO and all the other riders got on their motorcycles and performed the "All Rider Break", ramming into the Rock Great Leader and defeating it once and for all. OOO, Den-O, All Riders: Let's Go Kamen Riders

Super Hero TaisenEdit

14 Showa KR,9 Heisei Rider & 1 Neo-Heisei Rider(with Accel)

ZO was among the Kamen Riders caught up in the 'Super Hero Taisen' incident. He was presumably sent to the dimensional rift, under the pretense of being defeated, by Captain Marvelous while he was apparently hunting the Riders. When his and Tsukasa's ruse was revealed, ZO and the other Riders appeared through the dimensional wall. ZO then fought alongside all the other Kamen Riders and Super Sentai against Dai-Shocker and Dai-Zangyack's Shocker-Zangyack Alliance. Kamen Rider × Super Sentai: Super Hero Taisen

Kamen Rider TaisenEdit

As one of the 15 Showa Riders, ZO fought in the battle against the 15 Heisei Riders in Zawame City. At some point during the fighting he was defeated by a Heisei Rider, turning into a Lockseed.

ZO was later released with all the other sealed Riders by Kamen Riders Gaim and ZX. United, all 30 Kamen Riders teamed-up to take down the revived Badan Empire.

After Badan was defeated, ZO fought with the Showa Riders in a final showdown against the Heisei Riders. ZO took on Agito, striking each other with their Rider Kicks and falling to the ground after their power collided. The battle was ended when Rider 1 and Gaim reconciled on the differences of the two sides of Kamen Riders. Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai

ZO's attacksEdit


Break TootherEdit

Break Dousar

Break Toother.

Another of ZO's features within his insectoid head called a Break Toother (ブレイクトゥーサー Bureiku Toūsā?), a breathing apparatus stored around the mouthplate that shoots out vapors, bearing resemblance to fangs when extended.




Main article: Z-Bringer

ZO also rides on the Z-Bringer (Zブリンガー Zetto Buringā?), built by Dr. Mochizuki. Though resembling a regular motorcycle, the Z-Bringer changes along with ZO with ability to reach speeds up to 1300 km/h and resist heat up to 1000 degrees. ZO can use the Z-Bringer to execute the Z-Bringer Attack (Zブリンガーアタック Zetto Buringā Attacku?) Rider Break.

Picture Gallery (ZO's Arsenal)Edit

Legend Rider DevicesEdit

Kamen Ride ZO

Kamen Ride ZO

Kamen Ride ZO (カメンライドZO Kamen Raido Zetto Ō?) is the Kamen Ride Card which contains the power of Kamen Rider ZO. In All Riders vs. Dai-Shocker, Decade Complete Form Jumbo Formation performed the Final Dimension Kick, a variation of the Dimension Kick, transforming the Shōwa Riders, including ZO, and Heisei Riders into Kamen Ride cards for Decade to travel through as opposed to Final Attack Ride cards before hitting the target.

In theory, this card would allow Kamen Rider Decade to transform into ZO.

ZO LockSeed

ZO Lockseed

Kamen Rider ZO Lockseed (仮面ライダーZOロックシード Kamen Raidā Zetto Ō Rokkushīdo?): A Lockseed bearing the likeness of Kamen Rider ZO, created when ZO was defeated in the battle between the Showa Riders and Heisei Riders. Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai The core image depicts ZO's waist while the lid backside image depicts Berry. When inserted into a Sengoku Driver or when channeled through the Showa Rider Lockseed, it would allow an Armored Rider to assume ZO Arms (ZOアームズ Zetto Ō Āmuzu?). It is styled for Zangetsu and Mars in the toyline.

  • Transformation: ZO Arms: Daijizen Neo Seimeitai!
    • Squash: ZO Punch (ZOパンチ Zetto Ō Panchi?)
    • Au Lait: Z-Bringer (Zブリンガー Zetto Buringā?)
    • Sparking: ZO Kick (ZOキック Zetto Ō Kikku?)

Other Appearances Edit

Although Kou Domon has never returned to portray the character Masaru Aso, a generic "Kamen Rider ZO" character has appeared in later Kamen Rider live action productions.

Later Appearances in Kamen Rider/Super Sentai live action productionsEdit

Zyuranger Stage Show at Super Hero Korakuen YuenchiEdit

In a stage show where the Zyurangers are seen fighting their usual foes, Neo Organism shows up and ends up defeating them. Draft Redder, Draft Blues, Draft Keace, Kamern Rider ZO, Red Hawk, White Swan, Five Black & Black Turbo arrive to assist the Zyurangers.

Let's Go Kamen Rider net moviesEdit

  • In the 4th net movie Listen Quietly! The Tragedy of the 20th Anniversary Rider!, ZO was doing a speech to commemorate the film and the franchises 40th anniversary. The speech quickly became a rant about how his film came out in 1993 rather than 1991 and yet is considered a 20th anniversary production when it was the 22nd year of the franchise, how people confuse him with Kamen Rider J despite having a different look, the pronunciation and meaning of his name, how his enemy Doras was the villain of Movie War 2010 and the fact he didn't get to fight him. He then screams that he demands to know who is responsible for his misfortune but then he is dragged off the stage by 1, 2, OOO and Den-O.

Video GamesEdit

  • In The Great Battle IV, Kamen Rider ZO is a playable character and one of the pilots of the Compatible Kaiser along with Ultraman, original hero Fighter Roar and the Victory 2 Gundam (portrayed as human-sized here).
  • Kamen Rider ZO is also a playable character in the 2011 Nintendo DS video game All Kamen Rider: Rider Generation and Rider Generation 2 for the Sony PSP and Nintendo DS.

Kamen Rider Battle: GanbarideEdit

"To be added"

Behind the scenesEdit


In Kamen Rider ZO, Masaru Aso was portrayed by Kou Domon (土門 廣 Domon Kō?). As Kamen Rider ZO, his suit actor was Jiro Okamoto (岡元 次郎 Okamoto Jirō?).

Rider No.Edit

As the leading Rider protagonist of Kamen Rider ZO, Masaru Aso (Kamen Rider ZO) is labeled Kamen Rider #14 (仮面ライダー14号 Kamen Raidā Jūyongō?) and Showa Rider #14 (昭和ライダー14号 Shōwa Raidā Jūyongō?). Quiz! Decade Countdown!!

ReferencesEdit lists Kamen Rider ZO as Masaru Aso

Also seeEdit

Kamen Rider Series
Shōwa TV series: Kamen Rider | V3 | X | Amazon | Stronger | Skyrider | Super-1 | ZX | BLACK | BLACK RX
Heisei TV series: Kuuga | Agito | Ryuki | 555 | Blade | Hibiki | Kabuto | Den-O | Kiva | Decade | W | OOO | Fourze | Wizard | Gaim | Drive
Original films: Shin Kamen Rider: Prologue | ZO | J | World | The First | The Next
Other Media: Ultraman vs. Kamen Rider | Hyper Battle | G | Battle: Ganbaride | Climax Heroes
Manga & Books: Kamen Rider Spirits | BLACK | Eve -Masked Rider Gaia-
American Series: Saban's Masked Rider | Dragon Knight