Dr. Gero

Biodata

Feature	Value
Name	Dr. Gero (盖洛)
Alias(es)	Android 20 9
Species/Race	Originally human; later converted into an android 9
Gender	Male 9
Affiliation	Red Ribbon Army 9
Occupation/Role	Scientist; creator of androids and the biological weapon Cell 9 25
Status	Deceased; killed by Android 17 and Android 18 four years before the events of Chapter 48 9 48
First Appearance	First mentioned in the supplied material in Chapter 3; does not appear in person 3

Power Progression

Stage / Realm / Level	Chapter	Notes
Android 20	9	A retrospective reference confirms that Gero converted himself into an android and no longer had ordinary human physical needs. No combat-power value or transformation date is provided.

Background / History

Gero kidnapped the human twins who became Android 17 and Android 18. Android 18's original name was Lazuli. Their modifications erased most of their earlier memories, although fragments survived alongside their personalities and emotions 3 14.

He also constructed Android 16 as a fully mechanical combat unit. Attempts to correct its personality failed: it refused destructive missions, protected other lifeforms, and developed an interest in nature. Gero classified these autonomous behaviors as defects and placed the unit in storage 9.

His biological weapon, Cell, incorporated cells from Goku, Vegeta, Frieza, and Piccolo. Its intended route to Perfect Form required absorbing Android 17 and Android 18, whose Eternal Furnaces were key components of that evolution 25 52 55.

Gero eventually became Android 20. Android 18 later confirms that she and Android 17 killed him; their destruction of his laboratory nevertheless left some underground systems intact 9 48 49.

Personality

Gero treated independent behavior as a problem to be corrected rather than a quality to preserve. His assessment of Android 16 specifically condemned its refusal to destroy, protection of life, and unprogrammed autonomy 9.

His shutdown failsafe reflected distrust of his own creations. Chen Mo explains that Gero expected possession of the remote control to prevent Android 17 and Android 18 from escaping his authority 3.

His judgments also had limits. According to Android 17, Gero considered him stronger than Android 18, failing to recognize her superior body compatibility, combat instincts, and ki control. Android 18 later successfully operates two Eternal Furnaces despite the original single-furnace design 55.

Abilities & Skills

Android Engineering

Gero created both modified humans and fully mechanical androids 9.

• Human modification: Android 17 and Android 18 combine biological tissue with mechanical structures and Eternal Furnaces 9 52.
• Neural data implantation: Android 18 received extensive information during modification, including knowledge of the Red Ribbon Army's standard operating system 9.
• Preserved sensations and emotions: The modifications retained human emotional functions and pain nerves rather than eliminating them 14 31 55.
• Failsafe control: He designed an emergency shutdown remote capable of disabling the androids with a button 3.

Biological Weapon Design

Cell combines multiple species' cellular traits with Gero's implanted technical systems 25 53.

• Inherited traits: Namekian cells provide regeneration, Saiyan cells enable growth after near-death recovery, and Frieza's cells allow survival in a vacuum 53.
• Android tracking: An implanted cellular database allows Cell to detect the electromagnetic signatures of Android 17 and Android 18's energy engines 15.
• Built-in analysis: Cell uses Gero's radar, logical calculations, and database to track opponents, assess claims, and record new combat techniques 53 54.
• Design limits: Cell eventually pursues alternative absorption targets, including Majin Buu, explicitly seeking to exceed Gero's intended design 53.

Surveillance and Combat Analysis

Gero's insect-like reconnaissance robots collected the Z Fighters' combat data, technique details, and weaknesses for use in android development 47.

• The robots carry high-definition cameras and remote transmission modules that send footage back to their base in real time 47.
• Chen Mo describes the surveillance as extending to personal habits and daily activities; Yajirobe recalls Gohan feeling that the androids already knew his next moves 7.
• The devices can be repurposed: Android 18 reactivates and recodes a robot bee to monitor Chen Mo 48.

Equipment / Weapons / Items

• Northern mountain laboratory — A concealed underground Red Ribbon Army facility whose entrance resembles an ordinary cave 3 9.
• Emergency shutdown remote blueprints — Stored in a dedicated directory; the files are marked as transferred to external storage when Android 18 investigates 9.
• Incubation equipment — Used for Cell's development and Android 16's dormancy. The Cell incubation units have been carefully dismantled and removed before the twins arrive 9.
• Third-level database — Survives the main facility's destruction and contains a complete analysis of Cell's cellular structure, intended as a contingency 49.
• Maintenance and repair systems — Include calibration terminals, automated mechanical arms, repair chambers, and a main control computer 49 55.
• Backup furnace space — A redundant cavity in Android 18's chest designed for single-furnace failure, later repurposed to house a second active furnace 55.
• Combat-power testing device — Built to test Ultimate Cell, with an upper measurement limit of three billion; Android 18 overloads it after her dual-furnace modification 55.

Relationships

• Android 17 and Android 18 — Kidnapped human twins whom he modified and attempted to control through a shutdown failsafe. They ultimately killed him 3 9.
• Android 16 — Fully mechanical creation he stored as defective because it resisted destructive orders and protected life 9.
• Cell — Biological creation designed to absorb the twins and reach Perfect Form; retains Gero's databases and analytical systems 25 53 54.
• Goku and the Z Fighters — Surveillance subjects whose combat information and genetic samples contributed to Gero's weapons research 25 47.
• Tao Pai Pai — Chen Mo recalls Gero rebuilding him as Cyborg Tao Pai Pai in the main timeline, but cannot confirm whether that modification occurred in the current future timeline 4.

Story Role / Major Arcs

The Laboratory Search

Chen Mo's revelations about Gero's kidnapping, Cell, and the shutdown remote persuade Android 18 to investigate the northern laboratory. She and Android 17 find the incubation units missing, the remote blueprints removed, and Android 16 still dormant 3 9.

Surveillance records later establish that someone entered the laboratory two years before Android 18's report. Chen Mo suspects Trunks, but the supplied material does not confirm the intruder's identity 14.

A Cover for Chen Mo's Knowledge

Chen Mo repeatedly invokes Gero's records to explain information he actually knows through his previous-life knowledge. His claimed possession of an external storage device during negotiations with Cell is explicitly a bluff; his account of learning Kaio-ken from laboratory files is also identified as a lie 21 28.

Surviving Technology

Gero's equipment remains consequential after his death. Android 18 uses a recovered surveillance bee to watch Chen Mo, then returns to the surviving underground facility to investigate Cell's absorption limits and recalibrate her Eternal Furnace after a 0.3% efficiency loss 48 49.

The same facility supports Android 17's emergency treatment and Android 18's dual-furnace operation. Its computer estimates twenty years to repair Android 17 and warns that installing a second active furnace carries a 99.8% probability of bodily collapse—a risk Android 18 successfully overcomes 55.