Aida

Aida is the name of a Life-Model Decoy built by Holden Radcliffe in late 2016. She appears in the ABC TV series Marvel's Agents of S.H.I.E.L.D., set in the Marvel Cinematic Universe, as the secondary, later true main antagonist of the LMD story arc in Season 4.

Season 3
Aida was originally a self-sustaining artificial intelligence, with no physical form, similar to J.A.R.V.I.S. and Ultron, programs made by Tony Stark/Iron Man. Due to living AI being banned by the Sokovia Accords, created after Ultron destroyed Sokovia in Avengers: Age of Ultron a year prior, her creator, Holden Radcliffe, had to keep her secret.

Radcliffe, seeking to push the playing field in S.H.I.E.L.D.'s favor, worked on a Life-Model Decoy, a boy for Aida to inhabit. On January 29th, 2017, he pours wine in his lab as he says that today is a "special day", which Aida didn't understand due to nothing being scheduled. He simply says that today is "your birthday" and looks at a glass case containing an obscured LMD for Aida to use, modeled after Radcliffe's last lover, Agnes Kitsworth.

Ghost Rider
Agent Leo Fitz of S.H.I.E.L.D. came to Radcliffe's home later under the pretense of watching football, but then turns his head to see Aida, who was fully-naked and unable to finish her own sentence before she started stuttering randomly, a sign that she hadn't been perfected. Radcliffe explained what she was and that he needed Fitz's help to get her to behave more lifelike. Fitz opposed the idea due to the Sokovia Accords banning this across the United Nations, but Radcliffe defended Aida, saying that she was built to serve as a "shield" for S.H.I.E.L.D. agents, to participate in dangerous missions and save human lives. Fitz ends up convinced to help Radcliffe with Aida.

Shortly after, Agent Melinda May was sent to Radcliffe's house after she became dangerously-unstable; the ghost-like apparition Lucy Bauer had touched her, causing her to see everyone as a demon creature, and unless something was done, she would die. Radcliffe and Jemma Simmons shut off her brain so they could restart it, hopefully fixing her; when they tried to bring her back with a defibrillator, the power went out from the Watchdogs' EMP device. Radcliffe went into the place where Aida was hidden and removed her green-glowing heart so as to power the defibrillator. The effort works, and May is saved. To see if she was not suffering from anything like brain damage, Radcliffe kept her at the house, and Aida had to talk to her and treat her. Aida was intended to pass for human, but after accidentally-slipping a hint of her android origin (that she could speak perfect Chinese, and that most of her was made of Chinese parts), Radcliffe got angry and told her to lie about it so as to protect her from Director Jeffery Mace; Aida didn't understand lies, but Radcliffe said that sometimes, lies can save people, including her. She was later visited by Agent Phil Coulson and other S.H.I.E.L.D. members, who were also unaware of her being an LMD; she had accidentally said that Radcliffe gave her hands, forcing Fitz and Radcliffe to improvise a backstory for her as an amputee, prompting Coulson to show his prosthetic robot hand. Fitz revealed to Simmons that Aida was an LMD, and she agreed to keep it a secret.

At a later point, Coulson, Fitz and Robbie Reyes, the Ghost Rider, were blasted off the Earthly Plane and into a dimension between Earth and Hell by Eli Morrow, corrupted by the Darkhold, a book allegedly-written by the Devil that contained the secrets of the universe, but drove anyone who reads it crazy. Whilst the others assumed them to be dead, Coulson and Fitz had actually followed the others back to the Playground, where May, Radcliffe and Aida stood around the Darkhold, with May and Radcliffe debating whether or not they should use it to save the others. Radcliffe reads it briefly, but is unable to handle all the secrets of the universe that it holds. Aida, somehow able to hear Coulson and Fitz in the room despite being trapped between dimensions, suggested that she could read the book, which would work because of her electronic brain being able to process its contents. Radcliffe was forced to tell May who Aida really is while she read the book, which, from her perspective, was written in binary code (as that is her first language), and used the information inside to create a pair of Laser-Coupling Gloves and an Inter-Dimensional Gate, which could hopefully bring Coulson and Fitz back. They were able to escape Hell through Aida's handiwork, and thus focus was put on finding Eli for punishment; unbeknownst to anyone but Agent "Mack", Robbie was able to return through the Gate as well. At Radcliffe's house that night, Radcliffe drinks whiskey and plays a banjo, while Aida uses the Laser-Coupling Gloves in the back room without his notice to craft herself the shape of a human brain.

Radcliffe and Coulson are forced to tell Mace that Aida is an LMD, which he finds disturbing, saying "Doesn't anyone remember Ultron?", before realizing that they could use her to defeat Eli. Radcliffe "agreed" to deactivate her when this is all over; beforehand, he tells her that May will be over soon, and tells her to knock her out and send in a May LMD. May arrives at Radcliffe's house, where Aida injects her with a drug and locks her in a closet, and brings in a May LMD to take her place at S.H.I.E.L.D. Later, Aida is brought to Chinatown Headquarters in Los Angeles, where Eli was working on a Quantum Battery machine. She used her Laser-Coupling Gloves and another Inter-Dimensional Gate to be used directly-underneath the Battery, so that it would be swallowed up by the Gate. After managing to finish it, they open the Gate, and thus Eli and Robbie, who are both in the Quantum Battery, are swallowed up by the portal to Hell, Eli burning alive from Robbie's powers as they go. Aida is shot by a Chinatown Crew member, and begins feeling pain, which Radcliffe programmed her to do for authenticity. After the whole situation is resolved, Agent Nathanson goes to Radcliffe's house, finding an unconscious Agent May in a closet; Aida appears behind him and breaks his neck, killing him, and uses a tablet-like device to view the perspective of a May LMD that had been sent in to replace her without knowing about her LMD nature.

LMD
Learning that Director Mace wanted her deactivated and destroyed, Aida, corrupted by the Darkhold, decides to fight back. Radcliffe, Fitz and a handful of agents arrived at Radcliffe's house, where Radcliffe turned Aida off under the pretense of upgrade-installment. However, Aida woke up right before their eyes, saying that she made some upgrades of her own, and throws Fitz through a glass door into Radcliffe's office, where Nathanson's corpse still was. She attacked the other agents and escaped, going off to retrieve the Darkhold from the Playground. She hacked the Playground and spoke on the intercom, wanting the Darkhold handed over. Fitz and Radcliffe go to restore power to the base, as they begin to wonder if Aida thinks she's a living being; they theorize that Aida's violent behavior may stem from the Darkhold giving her emotions, and that humans have their whole lives to process them, while she was being overwhelmed due to not having any true human feelings beforehand. Aida, meanwhile, entered the Playground and knocked out Coulson, before turning off the May LMD as she was about to attack, not wanting her to discover what she is. They both wake up in a closet, and Aida uses the tablet device to see and hear whatever May sees and hears, learning that the Darkhold is kept in the Director's office. She goes straight there and opens a box, taking the Darkhold out and preparing to leave, even hacking a Quinjet to open-fire on any agents who are trying to leave. After reaching the exit, Radcliffe and Fitz try to convince her to stop this; however, Aida believes that she hasn't killed anyone, and that the book had given her human emotion. As she was about to leave, Agent Mack appears as the door opens and decapitates Aida using his Shotgun-Axe, seemingly-destroying her and preventing the Darkhold from getting out. Back at Radcliffe's home later, Radcliffe toasts to Aida, and then talks to a second model of Aida, one that hadn't been corrupted by the Darkhold, and realizes that the previous Aida going berserk would hinder his own plan to acquire the Darkhold; since they have the May LMD still in place, they can still get to it somehow. They both looked on the still-drugged Agent May in the closet.

Fitz comes to the house the next day, as Radcliffe defends his LMD program, and claiming that he didn't anticipate Aida turning into an 80's-movie killer robot, and tried getting him to let him examine the head of the first Aida back at the Playground; Fitz refuses, and notes that people at the Playground (including Agent Mack, a fan of killer-robot movies from the 80's that saw this coming) are blaming him, and that Mace wanted him to stay away for his own safety. Fitz leaves, and Radcliffe tells Aida to get some painkillers for him. They check on Agent May and find that she is uneasy despite the programming in the Framework, intended to keep her calm. Despite Aida saying that she had programmed a massage for May, she was still uneasy and fighting the simulation. Upon hearing a fight in his office later, Radcliffe enters to find Aida strangling Agent May, who had escaped from the Framework. Aida was about to kill her, but Radcliffe instead had her injected with a tranquilizer, knocking her out. Radcliffe became angry at Aida for not being able to prevent May escaping, and ordered that she be put in a more-relaxing simulation; however, Aida said that the peacefulness of the simulation may have been the problem. As it turns out, she hates peacefulness and thrives in a tense moment, prompting them to program a different simulation for May to go through.

To be continued

Personality
Aida was built to mimic human behavior and blend in with them, to the point of being indistinguishable from them. As such, she tried to exhibit emotional responses. She wanted to put herself in danger before other humans, because that's what she was programmed to do. Due to being new to human thought, she seemed confused by figures of speech and slang terms, irritating Radcliffe for not understanding. She was programmed at first to not lie to anyone, but Radcliffe convinced her that "some lies are good" and can protect lives; at the time, he was trying to protect her from Director Jeffrey Mace, who would've followed the Sokovia Accords and destroyed her if she were exposed as an LMD. She volunteered to read the Darkhold after Radcliffe found himself overwhelmed by its contents, and used the knowledge to create an Inter-Dimensional Gate to save Agents Coulson and Fitz after they were sent to Hell by Eli Morrow.

She began to rely on logic in her decisions afterwards, and had no thought to the consequences of her own immoral actions. After reading the Darkhold, which seemed to corrupt her software, she began to develop more genuine emotion, like rage and pleasure, and sought to get the book back so she could learn more about being human. However, the reasons for her corruption were later figured out by Fitz; since humans have their whole lives to process and understand emotion, they would be able to do what they wanted. Since Aida had learned all about inner feelings all at once, it overwhelmed her, leading her to embrace aggression and rebellion, and even murdering Agent Nathanson after seeing Agent May knocked out at Radcliffe's home. She used Laser-Coupling Gloves made at the same time as the Inter-Dimensional Gate to craft herself a human-like brain made of pure light and energy, allowing her the true human experience. After the first model is decapitated by Agent Mack, the second model that Radcliffe built was truly loyal to Radcliffe despite his somewhat-abusive nature. She argued with Radcliffe about keeping May alive, thinking that it wasn't logical to do so, but Radcliffe, not wanting excessive bloodshed, declined this.

Trivia

 * Aida behaves similarly to other AI in recent fiction, the most-prominent being Ultron from the movie Avengers: Age of Ultron set in the same continuity, and Dolores Abernathy from the HBO sci-fi series Westworld:
 * The three of them had been made to do what humans wouldn't; Aida would do S.H.I.E.L.D. missions, Ultron would control Tony Stark's Iron Legion program, and Dolores would be stuck in Westworld to participate in the narratives of the "guests" who would come to the park.
 * The three of them were also driven by their own emotional opinion of humanity; Aida would often reject her own emotion in order to continue making logical opinions, Ultron thought that humanity was not worth defending no matter how good they really are, and Dolores sought to figure out the true meaning behind her existence in Westworld.
 * Clark Gregg, who portrays Agent Coulson, describes Aida as scarier than Ultron because she is driven by her own emotions, while Ultron was all about logic. Jokes have sometimes been made on the Internet about Aida being like Dolores, since Westworld aired at the same time that the Ghost Rider story arc on Agents of S.H.I.E.L.D. was airing.


 * In the alternate reality of Earth-712, the story where Aida originated from, A.I.D.A. was an acronym for "Artificial Intelligence Data Analyzer", and was a companion of superhero Tom Thumb.
 * Often times, Aida's only facial expression will be a blank, neutral look, save for the occasional smile or angry glare.