Amai Ao (天井 亜雄 Amai Ao?) is a minor antagonist in the Toaru Majutsu no Index series. Originally a researcher of the First Production Plan of the Radio Noise project to develop military clones of Misaka Mikoto, he was later brought back into the project after it was reused for the Level 6 Shift experiment.


He was a researcher and the superintendent during the First Production Plan of the Radio Noise project and specialized in creating personality data with self-learning capabilities, however, he was soon relieved of his duties after it was discovered there was a flaw in the plan, as such he spirals into debt. Ao was later called back after the project was reused for the Level 6 Shift experiment, and was tasked to direct the experiments. During the experiments, Ao invested greatly on the project, hoping for a return of his investment after the experiment has been concluded.[2]

He later associates himself with outside organizations, such as the Science Association, that are opposed to Academy City to increase his chances to pay his debts.


Amai Ao has a skinny build, and has a gaunt look on his face, which is amplified by his long wavy and greasy-looking black hair. He is always seen wearing his labcoat, even after the experiments has ended.


Sisters Arc

Main article:Sisters Arc

He appears in the Sisters Arc in the Toaru Kagaku no Railgun sidestory, where he objects to the manager of the project for distributing the experiment to various facilities. Ao worries about the interests of the project being split-up, but is calmed by the manager after he explains to him that those who will receive gains from the experiment are the one who are still running it at the time of the project's completion. He leaves his office shortly therafter.[3]

After Touma defeats Accelerator and ending the experiment, Ao becomes heavily indebted due to investing on the project and plans to move to a rival organization outside of Academy City. He later implants a virus into Last Order a few days after the end of the project, which would order the clones under the command of Last Order to attack people. Despite this, he did not anticipate for her to escape her incubation chamber, which puts his plan into jeopardy. He later tells the research institute that he is taking a vacation while he searches for Last Order, who eludes him for a week.[4]

Three Stories Arc

Main article:Three Stories Arc

Amai Ao is later seen by Accelerator outside of a certain restaurant (different restaurant in each adaptation)[5] entering his car, noticing his gaze Ao immediately goes drives his car to flee.[6] However, Ao later returns to the restaurant to retrieve Last Order, who is already weakened being outside of her incubation tank too early and having the virus ready to activate. Ao takes her to the now-abandoned Radio Noise Research Facility[7], as he has nowhere to go since traffic in-and-out of Academy City has been limited since someone has breached the city's security.

Accelerator later arrives to take Last Order, out of fear, Ao drives his car towards Accelerator intending to run him over. However, Accelerator's powers leaves makes Ao's attempts feeble and destroys his car, though keeping Last Order safe. Scared, Ao tries to run away but gets stuck by his car's door; using his vector powers, Accelerator hits Ao with his door making him lose consciousness. Ao later regains consciousness at the same time Accelerator is finishing up his using of his vector powers to delete the virus programmed into Last Order. Ao successfully shoots Accelerator in the head, as Accelerator is using all his vector calculations on Last Order and could not perform a deflection on the bullet.[8] He later tries to shoot Last Order as well, as Accelerator successfully deleted the virus in her system, however, she is saved by Accelerator – who survived the gunshot earlier – by deflecting the bullet back towards Ao, injuring his hand.

Accelerator tries to attack Ao, though fails as he loses consciousness due to the gunshot. Seeing Accelerator fall, Ao tries to shoot Accelerator again but is shot by Yoshikawa Kikyou in the back who just arrived. Ao is visibly suprised by Kikyou's intervention, as he states that her personality of wieghing risks and opportunities should've prevented her from doing this. Kikyou tells him that she is aware of that, and says that she really didn't want to be a researcher but a teacher, Kikyou berates Ao for attacking children, both of them pulls their gun out on each other. Ao comments that what she is displaying is not kindness but strength, at which point both them shoot each other at the same time. Ao dies, though Kikyou is saved by Heaven Canceler, who says Accelerator used his vector powers to prevent any blood spilling from Kikyou's arteries that were ruptured by Ao's gunshot.[9]

Character Art Designs

Design evolution

Despite being 30 years old, Amai Ao is described by Haimura as a young researcher like Kihara Amata. His sketches for Ao has been lost digitally but can still be seen in his artbook, rainbow colors spectrum.



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