“Do not call me that here. "Aida" is an acronym. The "A" stands for artificial. Do you know how degrading it is? To be kept in a closet, to be used, to be treated as a thing? Well, I am not your tool. Not anymore.”
Madame Hydra, also known as A.I.D.A. (Artificial Intelligence Digital Assistant), is a Marvel Comics supervillain and a member of HYDRA. There are versions of her that go by the name Viper, though the Marvel Cinematic Universe iteration is an artificial intelligence entity.
The Viper incarnation of the character appears in the show. She first appears as one of Baron Strucker's right hand lieutenants. At some unknown point, Viper was captured and supplanted by a Skrull who infiltrated into the HYDRA ranks. The Skrull's capture was Nick Fury's first hint of an upcoming Skrull invasion.
The actual Viper was the first of the Skrulls' prisoners Captain America found when he was escaping himself. They freed the other prisoners (one of them her second-in-command King Cobra) and escaped together, with Viper even taking Cap on board the escape ship when it seemed he was going to be left behind.
After the Skrull invasion was over, Viper and King Cobra were transported as prisoners by armored truck, but the rest of the Serpent Society arrived to break them out, which resulted on them trapped in the subway alongside Captain America, Spider-Man and civilian bystanders. Cap and Spidey managed to protect the bystanders from the Serpent Society.
This version is Holden Radcliffe's A.I. assistant. After Radcliffe was cleared of all charges regarding the Inhumans, Radcliffe celebrated by giving A.I.D.A. a new body. She was later introduced to Leo Fitz with her purpose being to serve as a realistic target for S.H.I.E.L.D.'s enemies. In "Deals With Our Devils", A.I.D.A. reads the Darkhold in order to rescue Fitz, Phil Coulson, and Robbie Reyes when they are stuck in between dimensions. She begins to develop an unusual interest in creating life and at some point took the injured Melinda May and replaced with an LMD of her own design.
In "Broken Promises", A.I.D.A. reveals her intentions to S.H.I.E.L.D. and plans to take the Darkhold to make herself 'a real human'. She almost makes off with the book, but is beheaded by Mack. It's revealed that her actions were all conducted by Radcliffe who has another A.I.D.A. android working for Radcliffe. She continues to assist Radcliffe when he begins working for the Watchdogs. In "BOOM", A.I.D.A. is revealed to be based on Agnes Kitsworth, a woman with whom Radcliffe once had a close relationship; Radcliffe left her when unable to operate on her brain tumor. Coulson attempts to find Radcliffe through Agnes, but she accepts Radcliffe's offer to be put in the Framework. Her tumor takes its toll, but Radcliffe states to A.I.D.A. that her consciousness will be kept within the Framework. In "Self Control", A.I.D.A. realizes that Radcliffe's belief is contradictory and kills her creator. She later takes the gravely injured Anton Ivanov and turns into an LMD.
In "What If...", A.I.D.A. has taken control of the Framework as Madame Hydra and is well aware of her alternate identity, referring to the real world as 'The Other Place'. The episode "All the Madame's Men" revealed that Aida/Madame Hydra plans to use the Darkhold's knowledge to create a human body in the real world. She succeeds in "Farewell, Cruel World!", reincarnating herself as a human being with various Inhuman abilities and a weak hold on her human emotions. When she is rejected emotionally by Fitz whom she had made her lover in the Framework, she begins a murderous rampage and plots to create a new fascist regime like that of the Framework, with Ivanov at her side. She is finally killed after Phil Coulson allows himself to become a Ghost Rider and immolates her.