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This article details a subject that is considered canon. The subject of this article appeared in Dragon Ball Z anime series. The subject of this article appeared in Dragon Ball Kai anime series. The subject of this article appeared in the video games.

Alias No. 20 (20号, Nijū-Gō; FUNimation "Android 20")
Android No. 20 (人造人間20号, Jinzōningen Nijū-Gō; Literally meaning "Cyborg No. 20")
Epithet Dr. Gero (ドクター・ゲロ, Dokutā Gero)
Personal Data
Universe 7th Universe 7th Universe
Galaxy Milky Way, North Galaxies
Race Android
Birthplace Earth
Status Deceased
Gender Male Icon Male
Voice Actors
English Kent Williams
Japanese Kōji Yada
Professional Status
Affiliation(s) Red Ribbon Army Red Ribbon Army
Partner(s) Myū (Anime only)
Headquarters Dr. Gero's Laboratory
First Appearance
Manga Debut Chapter 337
Anime Debut DBZ126
Game Debut Dragon Ball Z: Super Martial Arts Legend
Image Gallery
Character Image Gallery

Gero (ゲロ), known primarily by his title, Dr. Gero (ドクター・ゲロ, Dokutā Gero), designated as Android No. 20 (人造人間20号, Jinzōningen Nijū-Gō; Literally meaning "Cyborg No. 20") was the genius scientist and a principal member of the Red Ribbon Army.[2] He was also the father of a member of the Red Ribbon Army.[2]


Member of Red Ribbon Army[]

Dr. Gero is one of the founding members as well as the head scientist of the Red Ribbon Army. He designed the Red Ribbon's weaponry, and created the first androids in the service of the Red Ribbon Army. He built Androids because mechs can be captured and used by the enemy while Androids can think for themselves.[3]

In the anime, another scientist, Dr. Flappe was his colleagues in charge of the Red Ribbon Army's Android Development Program.[4] They created No. 8, but is seen as faulty because of his good-spirited nature.

Vengeance Mission[]

After the Red Ribbon Army was defeated by Gokū, Dr. Gero went into hiding in his laboratory located in a mountain area north of Northern Capital. In this lab, he strived to create the ultimate fighting machine. Using an extremely intelligent tracking device disguised as an insect, he studied Gokū and Dragon Team for many years, observing the battle Gokū has with Tenshinhan, Piccolo Daimaō, Piccolo, and the Saiyans Raditz, Nappa and Vegeta.

The study of Gokū's power was interrupted when the Saiyan leaves for Namek, believing he had already compiled enough information; so he simply adjusted the androids' power levels to accommodate for Gokū's expected power increase, not accounting for the power level of Gokū's Super Saiyan form. Believing he had created the ultimate fighting machines, he finalizes his plans and constructed a series of Androids. No. 16 was modeled on Gero's dead son, a high-ranking Red Ribbon soldier long ago felled by an enemy bullet. In his affection, Gero made him powerful, but did not want him to be destroyed in battle, so he made him gentle.[1] While looking for fresh material for his experiments, Dr. Gero meets two notorious delinquents by chance, two siblings, a boy and a girl. He then kidnaps them and restructures them into No. 17 and No. 18.[4][5] However, the two became rebellious as they retain their human free will, so he deactivated them. According to No. 18, Dr. Gero destroyed all the other androids up to No. 15. No. 1 - No. 7 and No. 9 - No. 12 were completely artificial, but Gero could not control their personalities: too dark, too stupid, too nice, etc.[5] No. 19 was modeled after a doll decorating the command center of an enemy base, which Gero brought home as a trophy.[1]

To become immortal, Dr. Gero had No. 19 to turn him into an android, Android No. 20.[6] The only human part of him as an android is his brain, which was transplanted into his android body by No. 19. Dr. Gero had his brain transferred into an energy-absorbing model Android rather than an infinite-powered model, which would have allowed him far greater power reserves. No. 18 hinted that it may have been because he thinks that an energy-absorbing model android is easier to use as a host. Gero would later disguise his true identity by claiming that he is merely No. 20, and that Gero had died long ago.

While constructing the Androids, Dr. Gero discovered a way to fuse together the cells from the strongest warriors to walk the Earth (Gokū, Piccolo, Vegeta, Freeza, and Cold), and tried to create a supreme fighting entity. After realizing that his project would take too long to complete, he decided to turn attention to other matters and leave his supercomputer from his lab to complete the ultimate being, who he names Cell. Cell later speculated that Dr. Gero created him to dominate the Earth and later to destroy the entire universe.[7]


Dr. Gero is very cold-hearted, willing to do everything to achieve his goals, even kidnapping other people to use in his experiments. He also holds a strong hatred for Gokū after the latter defeats the entire Red Ribbon Army. He has the great own confidence in his technological skills and intellect, as he believes, even when the odds are against him, that him, or his creations, will succeed somehow. Gero also trusts his creations with his life, believing now that he has "improved" them, they will respect him as their master. Despite his evil side, however, he was not incapable of affection, as he modeled Android 16 after his deceased son and deliberately made it gentle in order to avoid the risk of him being destroyed in battle.


Dr. Gero's appearance consists of slightly tanned skin, blue eyes, a large bushy white mustache, and long hair. He also has a Red Ribbon Army logo located on the hat that hides his visible brain after he turns himself into an android. Dr. Gero's mechanical body also lacks the eyebrows he had in his old, organic form.


Body Modifications[]

Dragon Ball[]

Androids Arc[]

In Other Timelines[]

Trunks's Timeline[]

Cell's Timeline[]

In Other Media[]

Dragon Ball GT[]

Ultimate Android Arc[]


In spite of his attempts to kill Son Gokū through his creations, it could be said Gero wound up doing far more harm than good. While Gero's dream was ultimately achieved — the death of Son Gokū through his ultimate achievement, Cell, Gokū would only wind up becoming even stronger in the afterlife. This led to the discovery of Super Saiyan 3, as well as Fusion, which would only go on to make Gokū and his allies stronger than Gero had ever calculated.

Furthermore, the three of his strongest creations aside from Cell, would go on to ally with the Dragon Team or protect them in some way. No. 16, due to his death, was instrumental in Son Gohan attaining the Super Saiyan 2 transformation. No. 18 would eventually marry Kulilin, joining the Dragon Team; she would share her energy with the Genki Dama that led to Majin Boo's defeat, and go on to participate in the Tournament of Power. No. 17 became a park ranger, protecting the very planet that Gero wished to conquer, lent his energy to the Genki Dama that would defeat Majin Boo, and was the last fighter standing in the Tournament of Power, leading to the restoration of multiple destroyed Universes.

Creation and Conception[]


  • Despite being part of the Red Ribbon Army, which played a major role in Part I, Gero was never even mentioned until the Androids and Cell Arc in Part II.
  • According to Akira Toriyama, No. 20 and No. 19 were originally meant to be the androids which Trunks foretold of, however his former editor Kazuhiko Torishima said that the two looked outdated and ridiculous. So, rather than make them the final androids, the author opted to continue the storyline in favor of No. 17 and No. 18.[8][2]
  • In the Legacy of Goku video games, Gero has a metal named after him, used to construct particularly large androids such as the Destroyer: geromantium.