Masaru Aso

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

History
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, but fell asleep for four years until he awoke with an unconscious urge to protect "Hiroshi". Finding the boy, he fought with the monster Doras who was attacking him, transforming into Kamen Rider ZO in the process. Impaling Doras on a metal pole, he followed the boy, Hiroshi's grandfather Seikichi Mochizuki recognizing him.

He again transformed into ZO to protect Hiroshi from the Koumori Man and Kumo Woman, monsters sent after Hiroshi by Doras. He defeated the Kumo Woman, but the Koumori Man took Hiroshi to his father Doctor Mochizuki's lab. Following, he quickly defeated the Koumori Man before the Neo Organism, Mochizuki's ultimate creation, awoke, having imprisoned the Doctor for not letting it go free. ZO is defeated and absorbed by Doras, but hearing the music of Hiroshi's pocket watch distracts Doras, letting ZO break free and destroy it and the Neo Organism. He managed to rescue Hiroshi but couldn't save the Doctor. Bringing Hiroshi back to his grandfather, he rides away on his motorcycle.

Though he hated Mochizuki for making him a cyborg, Masaru eventually forgave him before learning the man was telepathically communicating with him.

Kamen Rider World
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.

All Riders Vs. Dai-Shocker
He arrives with the other Riders to fight Dai-Shocker's monster army, fighting Shocker Combatmen, the Butterfly Orphnoch, a Bakeneko, and the Slug Orphnoch before taking part in the All Rider Kick to destroy the Dai-Shocker Castle and Nobuhiko Tsukikage (Shadow Moon). He then became a Kamen Ride Card for Kamen Rider J as the giant Decade Complete Form to kick through to defeat King Dark. The day saved, he left with the other Riders through a dimensional rift.

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.

Super Hero Taisen
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 Taisen
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.

Due to the timeline alteration caused by Shocker, ZO became one of the brainwashed Riders in that timeline, donning the name of Shocker Rider ZO.

Following the Rider Grand Prix in which Drive emerged victorious over Kamen Rider 3, who was promptly integrated into the Great Leader of Shocker's Rider Robo form, ZO was among the Riders who appeared to attack Zeronos Zero Form and Denebick Buster only to be fought off by the turncoat BOARD Riders: Chalice, Leangle, Blade and Garren. Ultimately, the Double Riders 1 and 2 made their appearance having survived their apparent demise from within the Rider Robo, and broke Shocker's brainwashing on the fallen Riders, enabling all Riders to unite in a final battle against Shocker.

Unfortunately, ZO was among the Riders whose existence was erased by the Rider Robo. This fate, however, was rendered moot when the Rider Robo was finally destroyed by, restoring ZO's place in history.

Kamen Rider ZO
Kamen Rider ZO Rider Statistics: Ability Parameters:
 * Rider Height: 193 cm
 * Rider Weight: 83 kg
 * Maximum Jump Height: 130 m
 * Maximum Running Speed: 100 m per 1.2 seconds

Masaru is capable of transforming into "Neonoid #1", a mutant cybernetically enhanced creature based off of a grasshopper called ZO, who would be later called Kamen Rider ZO. Masaru first gained this ability by being surgically altered and genetically modified by Doctor Mochizuki. At first, he had no control over the transformation and it was triggered by emotional stress. But a bolt of lightning somehow corrected this problem while putting Masaru in a coma.

During his four year coma, the red core on his waist absorbed the biological energy of nature to enhance ZO's power to an unknown limit. Upon transformation, Masaru's body is enveloped in a dark green armored shell made of enhanced biological tissue with golden "veins" surrounding it. ZO's strength is able to crush special alloys up to 20 cm thick and he can scrap up to 50 cars in a single blow.

Special Attacks
 * ZO Punch (ZOパンチ)
 * ZO Kick (ZOキック)

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

Z-Bringer


ZO also rides on the Z-Bringer (Zブリンガー), 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) Rider Break.

Other Appearances
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.

Zyuranger Stage Show at Super Hero Korakuen Yuenchi
In a stage show where the Zyurangers are seen fighting their usual foes, Neo Organism shows up and ends up defeating them. Kamen Rider ZO,, , &  arrive to assist the Zyurangers.

Let's Go Kamen Rider net movies

 * 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.

The Masked Rider: Kamen Rider ZO
Through his appearance in ZO, Masaru Aso/Kamen Rider ZO is featured in The Masked Rider: Kamen Rider ZO.

The Great Battle IV

 * 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).

All Kamen Rider: Rider Generation

 * 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: Ganbaride

 * Kamen Rider ZO is a playable character in Ganbaride.

Kamen Rider SD

 * Although ZO didn't show up in any Kamen Rider SD medias like manga, OVA or video games. His SD counterpart was released however as a soft vinyl figure in one of the SD toylines along with Kamen Rider Shin.

Rider No.
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) and Showa Rider #14 (昭和ライダー14号).

Conception

 * One of ZO's conceptual designs would serve as the early basis for his successor Kamen Rider J.


 * Various art books reveal an earlier concept for ZO was that he was an alien warrior from outer space who came to Earth to stop an invasion.

Portrayal
In Kamen Rider ZO, Masaru Aso was portrayed by Kou Domon (土門 廣), who later played in . As Kamen Rider ZO, his suit actor was Jiro Okamoto (岡元 次郎).
 * In Kamen Rider Decade: All Riders vs. Dai-Shocker, ZO was portrayed by an unidentified suit actor.
 * In OOO, Den-O, All Riders: Let's Go Kamen Riders, ZO was voiced by an unidentified voice actor and portrayed by an unidentified suit actor.
 * In Kamen Rider × Super Sentai: Super Hero Taisen, ZO was portrayed by an unidentified suit actor.

Promotion

 * In the earliest trailer which was titled "Masked -Rider-", ZO's suit looks completely different from the film version. Many years later, Keita Amemiya finally confirmed it is actually Kamen Rider Black's suit since at that time they didn't have a final design.

Scrapped Development

 * Keita Amemiya had designed ZO's upgraded form. In this form ZO was wearing a red scarf, and his limbs and belt becomes silver. But it has never been adopted because the other producers changed their mind.


 * In an early conception of what would be known as a "Legend Rider" form, popularized in the Heisei Kamen Rider Series Phase 2, an upgraded ZO form designed for the unmade sequel of Kamen Rider ZO in 1994 featured ZO utilizing the powers of the 7 Senior Rider (せんぱいライダー) by remodeling his body parts.
 * Kamen Rider V3: Equipped a radar on ZO's left hand
 * Riderman: Equipped a weapon on ZO's right hand.
 * X: Equipped two flippers on ZO's feet.
 * Amazon: Upgrated ZO's teeth and bite ability.
 * Stronger: Equipped a on ZO's shoulder.
 * Skyrider: Equipped two wings on ZO's back.
 * Super-1: Equipped a rocket on ZO's waist.

Appearances

 * Icon-zo.png Kamen Rider ZO
 * Icon-kr.png Kamen Rider World
 * Icon-decade.png Kamen Rider Decade: All Riders vs. Dai-Shocker
 * Icon-ooo.png OOO, Den-O, All Riders: Let's Go Kamen Riders
 * Icon-fourze.png Kamen Rider × Super Sentai: Super Hero Taisen
 * Icon-gaim.png Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai
 * Icon-drive.png Super Hero Taisen GP: Kamen Rider 3