Masaru Aso

is the main protagonist of Kamen Rider ZO. Transforming into a grasshopper mutant known as , he seeks to protect a young boy from monstrous creations that have been sent after him.
==History==
Masaru was originally an assistant to Dr. 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 Dr. Mochizuki's lab. Following, he quickly defeated the Koumori Man before the Neonoid, 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 Neonoid. 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.http://www.all-rider.jp/character/index.html
===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 Kingdark. 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 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 against Dai-Shocker and 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. 
===Super Hero Taisen GP: Kamen Rider 3===
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.
=== ===
Though he was seemingly erased as a result of Asmodeus’ manipulations, he was restored back into existence once Touma Kamiyama had helped Shotaro regained his passion in drawing out the superheroes that he wants to draw out.
During the climatic final battle itself, he can be seen fighting alongside , and Kamen Rider Kiva.
==Appearances in other media==
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 productions===
====Zyuranger Stage Show at Super Hero Korakuen Yuenchi====
In a stage show where the Zyurangers are seen fighting their usual foes, Neonoid 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.
===Video Games===
====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===
*ZO didn't show up in any Kamen Rider SD media such as 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.
==Personality==
to be added
==Kamen Rider ZO==
Kamen Rider ZO
 
;Rider Statistics. (2001). Masked Rider Chronicles: A History of Cyborg Soldier's Battle. p. 208-209. ISBN 978-4812407837.Kamen Rider Official Data/Perfect File.Hobby Japan. (2005). S.I.C. Official Diorama Story: S.I.C. Hero Saga. Vol. 1. p. 72. ISBN 978-4894253896.
*Rider Height: 193 cm
*Rider Weight: 83 kg
;Ability Parameters
*Maximum Jump Height: 130 m
*Maximum Running Speed: 100 m per 1.2 seconds
Masaru is capable of transforming into , a mutant that partially incorporates the grasshopper gene and machine called ZO, who would be later called Kamen Rider ZO. Masaru first gained this ability after being forced to undergo surgery and genetic modification by Dr. Mochizuki, who was driven by madness. At first, he had no control over the transformation and it was triggered by emotional stress. A bolt of lightning somehow corrected this problem while putting Masaru in a coma. During his four year coma, the on his waist absorbed the biological energy of nature to enhance ZO's power to an unknown limit.
Having undergone organic remodeling, Masaru has a strong body and special abilities even before transformation. He has extraordinary durability, as seen when he withstood a direct hit from Doras's Moleculaser, and was able to transform immediately afterward. ZO also possesses a healing factor to some degree, as he is able to recover from injuries in a short period of time.
Masaru has several telepathic abilities. He can telepathically communicate with grasshoppers, which enables him to see the locations where they have been or listen to the conversations of those around the insects. Dr. Mochizuki was communicating with him psychically over long distances as well. He also repaired Masaru's broken pocket watch through unknown means.
Upon transformation, Masaru's body resembles a locust, enveloped in a dark green armored shell made of enhanced biological tissue covering the entire body with golden biological lines. 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
*
*
==Equipment==
===Break Toother===
Another of ZO's features within his insectoid head is the , a breathing apparatus stored around the mouth plate that releases vapors from holes in the golden lines on the back of his head, bearing a resemblance to fangs when extended.
===Z-Bringer===
ZO also rides on the , 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 Rider Break.
==Legend Rider Devices==
==Relationships==
===Allies===
*Hiroshi Mochizuki: to be added
*Seikichi Mochizuki: to be added
*Reiko: to be added
*Kuroda: to be added
*Nishimura: to be added
*Miyazaki: to be added
===Enemies===
====NeonoidS====
*Neonoid/Doras: to be added
*Kumo Woman: to be added
*Koumori Man: to be added
==Behind the Scenes==
===Portrayal===
In Kamen Rider ZO, Masaru Aso was portrayed by , who later played in . As Kamen Rider ZO, his suit actor was .
*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.
===Rider No.===
As the leading Rider protagonist of Kamen Rider ZO, Masaru Aso (Kamen Rider ZO) is labeled and . 
Before this definition in the Decade net movies, Kamen Rider ZO was considered Kamen Rider #13, as Kamen Rider Black RX was originally seen as a form change for Black rather than a separate Rider.
===Concept Art===
ZObyShotaroIshinomori.jpg|A design decided by Shotaro Ishinomori. Details such as biological treatment and joint seams are specified.
ZOdesign1.jpg|ZO’s styling study design. This becomes an ambitious design that eliminates the installation of protectors and transformation belts.
ZOdesign2.jpg|ZO's unused design.
ZO_prototype_concept_art_design.png|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.
===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.Director's interview in Blu-ray disk
===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 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: Upgraded 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.
==Notes==
*In reality, the best indicators for which is ZO and which is J is that J has stripes in various shades of green and a seashell-like gem on his waist while ZO has a round gem with gold vein-like patterns on his body.
**In some official material, ZO would be depicted with his Break Toother extended, in order to further distinguish him from J.
==Appearances==
==See also==
===Footnotes===
==Navigation==
Category:ZO Characters
Category:Kamen Riders
Category:Movie Riders
Category:Heroes
Category:Showa Era Riders
Category:Cyborg Riders
Category:Movie-exclusive Characters
Category:Primary Riders