Dr Gero's History
Background
Dr. Gero is the head scientist of the Red Ribbon Army; he was a founding member of the Red Ribbon Army to begin with and was also effectively in control. 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.[2] Another scientist, Dr. Flappe is named as Android 8's creator. Daizenshuu 7 addresses this inconsistency by stating that Dr. Flappe and Dr. Gero were colleagues in charge of the Red Ribbon Army's Android Development Program. The Red Ribbon Army is not the primary reason for Dr. Gero's desire to create androids and cyborgs, as he reveals in GT that he always dreamed of replacing the entire human race with artificial beings even before Goku defeated the Red Ribbon Army.
Dr. Gero's son was a high-ranking Red Ribbon soldier, but he died when he was hit by an enemy bullet; Gero later modeled the powerful Android 16 after his dead son. At one point, Dr. Gero brought home a doll decorating the command center of an enemy base as a trophy, which he later used as a model to design Android 19. He fathered this child with the human who was Android 21's base.
After the Red Ribbon Army is defeated by Goku, Dr. Gero goes into hiding in his laboratory located in a mountain area north of North City. In this lab, he strives to create the ultimate fighting machine. Using an extremely intelligent tracking device disguised as a ladybug, he studies Goku and the Z Fighters for years, observing the fights Goku has with Tien Shinhan, King Piccolo, Piccolo, and the Saiyans Raditz, Nappa, and Vegeta.
Dr. Gero ceases the study of Goku's power when the Saiyan leaves for Namek, believing he had already compiled enough information; so he simply adjusts the androids' power levels to accommodate for Goku's expected power increase, not accounting for the power level of Goku's Super Saiyan form. Believing he had created the ultimate fighting machines, he finalizes his plans and constructed a series of Androids. Android 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. 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 Android 17 and Android 18. However, the two became rebellious as they retain their human free will, so he deactivated them. According to Android 18, Dr. Gero destroyed all the other androids up to Android 15. 1-7 and 9-12 were completely artificial, but Gero could not control their personalities: too dark, too stupid, too nice, etc.
Android 19 was modeled after a doll decorating the command center of an enemy base, which Gero brought home as a trophy. To become immortal, Dr. Gero has Android 19 to turn him into an android, Android 20. The only human part of him as an android is his brain, which was transplanted into his android body by Android 19. Dr. Gero has his brain transferred into an energy-absorbing model Android rather than an infinite-powered model, which would have allowed him far greater power reserves. Android 18 hints 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 Android 20 and that Gero had died long ago.
While constructing the Androids, Dr. Gero discovers a way to fuse together the cells from the strongest warriors to walk the Earth (Goku, Piccolo, Vegeta, Frieza, and King Cold), and tries to create a supreme fighting entity. After realizing that his project would take too long to complete, he decides 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 defeat the Earth and later to destroy the entire universe.
Androids Saga
Two years after Namek's destruction, after easily slaughtering Frieza, his soldiers and his father, Future Trunks informs the Z Fighters that two extremely powerful Androids created by Gero will appear in three years. Three years later, on May 12 of Age 767, at 10:00 am, two Androids appear on an island nine miles south-west of South City: Android 19 and Android 20. They attack Yajirobe in his hovercar, shortly after the latter gives the Z Fighters a sack of Senzu Beans, and descend into the city. Together, they start a killing spree and do not show any mercy or regret; during one point, #20 grabs a man from his car and crushes his skull like a grape, never changing his stoic expression. The Z Fighters struggle to find them, due to the androids having no ki, but Yamcha is the first to find them, attracted to the scene by the scream of a woman. They then ambush him, with Yamcha initially believing them to be two civilians and trying to tell them to evacuate until he noticed the Red Ribbon logo on Android 20's cap, with Android 20 smugly confirming that they are the androids he's referring to.
Before Yamcha can act, Android 20 demonstrates a deadly power: Dr. Gero's latest design for Androids, an energy absorbing function. Using a small red jewel embedded in his hand, he grabs Yamcha by the jaw, punches a hole through his chest, and saps his life-force. Goku, Piccolo, Krillin, and Tien Shinhan detect Yamcha's fast dropping energy and find him fatally injured by Android 20. Krillin takes the dying Yamcha back to Bulma for a Senzu Bean. Android 20 is surprised that the Z Fighters knew that he and 19 were androids even though they gave no indication. He also says that the Z Fighters also seemed to know where he and Android 19 would be and gathered in anticipation. #20 asks how this is possible, but Piccolo refuses, saying that they will have to obtain the information by force. Android 20 says that they will do just that. However, Goku suggests that they move to another location since there are too many innocent people around. Android 20 takes it as meaning that he doesn't want anyone to get in the way and single-handedly destroys half the city and its populace with his Bionic Punisher technique. An enraged Goku tells the android to stop and charges in, hitting Android 20 in the head with a punch and knocking off his hat in the process, revealing a seemingly organic brain is revealed underneath. Android 20 detects that Goku is unsatisfied with his solution to finding an uninhabited place. Android 19 says the Z Fighters will be unable to defeat them no matter where they fight, but Android 20 tells Goku to choose his place of death, calling him by name. Piccolo wonders how Android 20 knows Goku's name, and Android 20 says that he knows them all, naming Piccolo and Tien as well. Police sirens are heard approaching, and Goku says that they can ask questions later, then takes off. The androids, Piccolo, and Tien follow him.
As the group with the androids flies over a deserted plain, Android 20 says they will fight there because it is adequate for that purpose. Goku does not object and the group lands. Piccolo realizes that the plain is surrounded by rocky mountains, and that the androids are planning on hiding among these if necessary. Android 20 begins to explain to Goku that they have been watching his battles with miniature surveillance drones ever since he defeated the Red Ribbon Army, looking for a weakness. 20 says that only the humiliated Dr. Gero remained after the Army's defeat, and Piccolo says that 20 is talking as if he was Gero himself. 20 lies, saying that he is the creation of Dr. Gero and that the doctor himself is no longer alive. Goku then asks if they observed his battles on Planet Namek, and Android 20 responds that they had sufficient data by that time, thus it was unnecessary, as the androids' power levels were adjusted to accommodate for Goku's expected power increase. Goku tells Android 20 that he has missed something. Android 20 and Android 19 are surprised to hear this, and Piccolo says that it is a fatal mistake not to know about the Super Saiyan. Goku then powers up and transforms, and the burst of ki alerts Gohan, Krillin, and Yamcha to the location of the battle. 20 admits that Goku has far exceeded his calculated limits, however, he says that 19 can still handle Goku. Goku says that he will find that out for himself, and charges in to do battle.
Goku, at the start, does well in the fight, completely overwhelming 19. Android 20 is concerned that Android 19 will run out of energy before he can absorb any of Goku's power. However, the Saiyan's Heart Virus manifests at that exact moment and hinders his performance. Goku, visibly exhausted, decides to try to finish 19 with a Kamehameha. Upon seeing the blast, 19 and 20 are overjoyed, and 19 simply absorbs the blast with his right hand. 20 notes that 19's power has increased while Goku's has dramatically decreased. Krillin gives Goku a Senzu Bean, hoping it will help him. Android 20 realizes that the bean is indeed the legendary Senzu, and Yamcha is now again optimistic about Goku's chances. However, the Senzu could not cure Goku's illness and the Saiyan can no longer maintain his Super Sayan form. 19 jumps, landing on Goku's chest and grabbing him by the neck to absorb his energy. The rest of the Z Fighters fly forward to help Goku, however, they are intercepted by Android 20, who tells them that they will not intervene in the battle and warns them to try at their own peril. Piccolo says that he will and kicks at 20, but 20 dodges and hits Piccolo with Eye Lasers. Piccolo falls to the ground, and 20 says that his actions were bold, but stupid. Before Goku can be killed, Vegeta saves him by kicking 19 in face, declaring he will be the only one to kill Goku.
The Z Fighters and the androids are both stunned by the sudden appearance of Vegeta. Piccolo, lying on the ground, suddenly gets up. He reveals that he was simply faking defeat in order for the android to let his guard down, telling Gohan that it would take more than one blast to beat him. Vegeta says that he saw everything, and tells Goku that he is a fool for turning Super Saiyan even though he noticed the anomaly in his body and kicks him forward into the air. Piccolo grabs him, and Vegeta says that someone should drag Goku home and give him the Heart Medicine. Yamcha says that he will, as he seems to be the least useful one there. Piccolo tells Yamcha to take some of the medicine as well, as the virus could be contagious. As Yamcha flies off with Goku, Android 19 watches and prepares to give chase, but Android 20 tells him not to, as it could be fun to save the best (Goku) for last. 20 says that they can take care of the rest of the Z Fighters now, and that things will be more interesting since Vegeta has joined them. 19 asks if he can kill Vegeta, and 20 agrees after calling him greedy and saying that in exchange he will take the other four. Vegeta tells 19 that from his observations, the androids are not as strong as they were said to be. He tells 19 that he knows about their energy absorption through the palms, but 19 replies that he already knows Vegeta's abilities. Vegeta says that Saiyans cannot be reduced to numbers and wonders if androids can feel fear, then transforms into a Super Saiyan. The Z Fighters and androids are both surprised at this development, and Krillin says that he thought a Super Saiyan had to have a pure heart. Vegeta says that his heart is pure, but pure evil. He tells how he endured a brutal training regimen before reaching his own limits, and became a Super Saiyan due to his rage against himself. Android 20 tells Vegeta that he is still no match for them, and 19 charges towards Vegeta.
Android 20 can only watch in horror as Vegeta aggressively beats 19 around. Terrified, Android 19 scrambles out of the crater and begins to run away. Vegeta rises into the air and prepares to destroy Android 19 when Android 20 verbally intercedes, demanding he stop. Vegeta tells him that he will deal with him after. After powering up sufficiently, Vegeta unleashes a Big Bang Attack on the fleeing android, which creates a massive explosion, stunning the onlookers. When the smoke clears, only Android 19's head remains. Vegeta lands near Android 20 and powers down to his base form, and tells Android 20 that he has lost a lot of energy and that this is his chance to defeat him. Android 20 wonders what sort of trick Vegeta is trying to pull. Vegeta asks why Android 20 said he had no hope, and Android 20 tells Vegeta that even though he has exceeded their calculations, he is more powerful. Vegeta asks 20 to show him. Intimidated, Android 20 then runs away, heading for the nearby rocks as Piccolo had feared earlier.
Android 20 quickly hides from a rejuvenated Super Saiyan Vegeta and watches him from a distance. Impatient and tired of searching, Vegeta decides to flush 20 out by destroying some of the area, so he flies into the air and throws a Photon Bomber towards the ground. Krillin yells for him to stop, as rest the team could get caught in the blast. Seeing his chance, Android 20 steps in front of the blast and absorbs it through his palms. Seeing this, Vegeta immediately flies towards 20, who quickly disappears. Vegeta chases after him, but is upset to discover that 20 is quicker and managed to leave his sight. Android 20, watching Vegeta from above, says that he has become too dependent on tracking ki and has lost his eye for movement, however, he admits that he did not count on so much power from Vegeta. Although he believes the most logical option is to return to his lab, he wants to avoid that if at all possible. He then spots Gohan, Tien, Piccolo, and Krillin searching for him and decides to steal their energy in order to become powerful enough defeat Vegeta.
Android 20 decides to attack Piccolo first, as he is the strongest after Vegeta. He ambushes Piccolo from behind to absorb his energy and covers his mouth so that he cannot call for help. 20 tells Piccolo that the others cannot see them, as he knows where they all are. However, Piccolo telepathically calls out to Gohan, who detects the constant decrease in his ki and flies over to help. As Android 20 tells Piccolo that he is almost out of energy, Gohan arrives and hits Android 20 from behind, knocking him off of Piccolo (this also knocks off the android's hat). Krillin, Tien Shinhan, and Vegeta sense Gohan's ki, and surround Android 20 upon reaching the area. Android 20 is surprised at the arrival of the other Z Fighters, but decides to stall for time and absorb more energy from the others before fighting Vegeta. Gohan tells Krillin to give Piccolo a Senzu Bean, which he does. Piccolo then descends down to face Android 20, removing his weighted clothing. He tells Vegeta not to interfere because he wants to face Android 20 personally. Vegeta responds that he does not care if Piccolo gets killed, but says that he will only be giving Android 20 more energy. Android 20 thinks to himself that this is another chance to absorb more of Piccolo's energy, but Piccolo quickly disappears from his sight and knees him in the face. He tries to fight Piccolo head-on, but Piccolo is superior by far as a result of the three years of intense training with Goku (and also the fusion with Nail). Piccolo mercilessly severs the android's right arm and prepares to destroy him, but is distracted by the arrival of Future Trunks. Believing he has miscalculated too much, Android 20 decides to retreat into his lab, in order to activate Android 17 and Android 18, although he laments that he cannot fly away without being spotted and decides to run away on foot. Suddenly, Bulma arrives by airplane with Yajirobe and the present, infant version of Trunks in tow. Seeing an opportunity to escape, 20 declares that 17 and 18 will come and avenge his defeat, before firing a large Photon Wave at Bulma's plane. With a cloud of smoke and dust covering his tracks, Android 20 runs away into the rocky mountains. Having recognized him as Dr. Gero, Bulma notifies the Z Warriors about the approximate area of his laboratory and they depart for the mountains near North City. Vegeta, more overconfident than usual thanks to his new Super Saiyan power, goes off on his own to challenge the androids, so the rest of the group becomes determined to find Gero or his lab before Vegeta does.
Meanwhile, as he hides among the rocks, Dr. Gero sees Vegeta and then Future Trunks fly overhead in the direction of his lab. He initially thinks that it must be a coincidence, and that they cannot know its location because only a handful of scientists know of its existence. Thinking back, he recognizes Goku's close friend, Bulma as the heir to Capsule Corporation and thinks that she may have learned about him through her father. Suddenly, he sees Piccolo, Krillin, and Tien Shinhan flying in the same direction and realizes that they are indeed heading for his lab to destroy 17 and 18 before he can activate them. He heads off after them, thinking that their need to find its precise location will give him enough time. In the anime, as he approaches his lab, Gero senses Krillin nearby and ambushes him. Before he can kill Krillin, Gero senses Piccolo nearby and decides to spare him in his hurry to activate his Androids. Dr. Gero quickly reaches his lab, and leaps up into the cave which houses it. As he is about to enter, however, his sensors detect something, and he turns around to see Krillin looking at him. Gero thinks that Krillin will not be able to do anything, and opens the door to his lab. He then tells Krillin that even if he calls the others, they will be too late now. Krillin then raises his ki, and Piccolo, Tien, Vegeta, and Trunks all sense it.
Gero, inside his lab, says that he would have preferred not to activate 17 and 18, but that he has no choice now, and hopes that he has made them obedient. He then activates Android 17, while holding his Shut Down Remote. After awakening, Android 17 says good morning to Dr. Gero. When Gero comments on his politeness, Android 17 says that Gero is his creator, though he eyes the remote. Relieved that Android 17 appears to be operating properly, (in Dragon Ball Z Kai, Gero believes he successfully reprogrammed 17's personality), Gero then activates Android 18. Android 18 is polite to Gero as well, though she also eyes the remote. She comments on the fact that Gero has made himself into a android, and Gero says that he wanted eternal life. He also says that he previously devoted too much time to their infinite energy reactor, (in Dragon Ball Z Kai, Dr. Gero explains that in order for their infinite energy reactors to function, he had to disable the behavioral limiters wired into their firmware), and that they would not obey him. He then relates the news that the Z Fighters are en route, and tells the twin androids to kill them all, which they agree to do. The Z Fighters soon arrive and begin attempting to break in. This momentarily distracts Gero, and 17 steals the remote from him. Much to Gero's horror, he then crushes the remote and tells Gero that he will not put them to sleep again.
Suddenly, Vegeta blasts the door down and the androids are surrounded by the Z Fighters. Dr. Gero tells Android 18 and Android 17 to kill the Z Fighters, mentioning that they destroyed Android 19 and almost killed him. Android 17 asks if 19 was an energy absorption model and the one who converted him into android, and Gero replies that he was. Android 18 asks if Gero went back to the old energy absorption model on a more recent android because infinite energy models like she and Android 17 were too powerful to control. Dr. Gero tells them that it does not matter now, and orders the pair to kill the Z Fighters, but 17 says that they will fight when they want. Gero is even more upset when Android 18 begins inspecting a chamber labeled "16". Android 18 notices that 16 is also an infinite energy model and asks how the android inside is different from them, but Gero tells her to get away from 16's chamber. Android 17 tells Android 18 to activate Android 16, but Gero tells them not to, as 16 was a failure and would put the entire world at risk. Android 18 questions why he kept 16 around, and Gero says he was planning on fixing him later. Android 17 says that he has a much higher power rating than Android 16, and tells Android 18 to activate him. Gero calls the pair failures, and says he will deactivate them all for good. Android 17 reminds him that the remote is destroyed, but Gero says he can build another. Once more, he yells at Android 18 not to activate Android 16, but suddenly Android 17 brutally murders Gero by impaling him from behind with his arm, decapitating him with a swift kick, and then stepping on Gero's still-living head. His remains are later destroyed along with what seems to be the rest of his laboratory at the hands of Future Trunks when he fires the Buster Cannon with the intention of destroying Android 17 and Android 18.
Majin Buu Saga
In filler, Dr. Gero is permitted by King Yemma to keep his android body while entering Hell but the reason is unknown. Along with Cell, Frieza, King Cold, and the Ginyu Force, Dr. Gero watches the final battle between Goku and Kid Buu, being one of the very few people cheering for Kid Buu.
