Dr. Gavin Archer is the chief scientist of Project Overlord at the Cerberus facility on Aite. Dr. Archer is the only surviving member of the Project Overlord research team. Upon arrival on Aite, Archer directs Commander Shepard to prevent the escape of the rogue VI that has taken over the facility.
Mass Effect 2 Edit
When Commander Shepard arrives at Hermes Station on Aite, Dr. Archer reveals himself on a nearby video monitor. He explains that a rogue VI has taken over and he has locked himself inside a computer room at the far side of the base. After Shepard prevents the VI from uploading itself off-world via the destruction of the base's satellite dish, he comes out of hiding. Upon first being asked the reason behind all this, Archer explains it as "Man's reach exceeding his grasp."
He explains his brother, David Archer, volunteered as a test subject for the project merging a human mind and a VI, and the results have been "less than satisfactory." When Shepard comments about the destructive progress, Dr. Archer explains, "Even amid chaos there are lessons to be learned." He explains that David could not handle the merger, and is "more like a virus now", infecting the world's networks and seizing all technology he can find. He explains that if the VI was to ever get off-world, it would be a "technological apocalypse", with every computer turning against its user. He tells Shepard the only way to stop David is to infiltrate the fortified laboratory in Atlas Station, but only after overriding the security at nearby Vulcan and Prometheus Stations.
Upon further investigation it is revealed that David is a savant, a high functioning autistic whose photographic memory and mathematically gifted mind virtually made him a human computer. In addition, because the very basis of geth communication is founded upon simple calculations communicated phonetically, it is revealed that David could already commune rudimentarily with the geth even before his interface with the VI.
Gavin saw the potential of his brother's mathematical mind interacting with geth technology, and when the Illusive Man threatened to shut Overlord down due to a lack of results, Gavin accelerated the project by forcibly connecting his brother to the VI, causing him a lot of pain in the process.
While Shepard battles David in the Atlas Station core, Gavin begs David to stop his upload, and enters the core when Shepard drops David's shields. After viewing Shepard's horror at the state of David, Gavin asks to treat his brother for all the harm caused to him, but to continue the experiment, refusing to apologise: "If my work spares a million mothers mourning the loss of a million sons, my conscience will rest easy." But when Shepard asks if he would sacrifice his brother's happiness for his own ambition, Gavin takes a closer look at David, realizes his actions were wrong, and asks Shepard to let him continue caring for his brother.
Gavin violently objects to the notion of Shepard releasing David, attempting to shoot the Commander but receiving a gun in his face instead. The Commander can pistol-whip Gavin. Either way, Gavin is warned that should he even contemplate coming for David, Shepard will not hesitate to kill him. Gavin asks where Shepard will take his brother; the Commander responds that Grissom Academy will take care of David.
If Shepard keeps David hooked up, Shepard punches Gavin tells him the only reason he survives is because his research may prevent war with the geth.
Mass Effect 3 Editattack from the Illusive Man's troops.
If Shepard released David and placed him under Grissom Academy's care in 2185, Gavin begins to regret involving his brother with Cerberus; he refused to obey the Illusive Man's instructions to find a new subject to replace David and eventually fled after erasing all information on Project Overlord, an action that resulted in Cerberus placing a kill order on him. Despite David's release to Grissom Academy, Dr. Gavin Archer still assists in the war effort.
However, if Shepard released David to Grissom Academy but then does not come to the facility's aid on time after being besieged by Cerberus, David is killed in the ensuing attack. Then, if Shepard meets Dr. Gavin Archer later, Gavin pulls out a pistol, walks away, and a gunshot rings out. Even if the Grissom Academy mission was completed beforehand, Shepard can lie to Archer and claim they do not know David's fate, which also causes him to commit suicide.
If Shepard allowed David to stay at Project Overlord, Gavin reveals that the data on controlling the geth from Project Overlord was in fact useful, and David eventually calmed down his emotions somewhat but one day just stopped responding to any stimuli at all. Gavin then had to pull the life support plug on David as a mercy killing. This caused Gavin to eventually defect from Cerberus since the guilt finally became too much. After the ex-Cerberus scientists are rescued, Dr. Gavin Archer assists in the war effort.
If Shepard never dealt with Project Overlord, Gavin introduces himself for the first time and gives a brief rundown on the project. Once prompted about why he defected, he reveals that David eventually had gone out of control to the point of killing several scientists. Eventually, Cerberus used nuclear weapons on the base. Dr. Archer never joins the war effort following the events at Gellix.
Should Shepard resolve the situation with the quarians and geth before heading to Arrae, and not save David at any point, revealing to Gavin that the geth are no longer a threat to organic civilizations causes him to realize that David's suffering was for nothing. He then walks off and a gunshot is heard.