Introduced as a point-of-view character in the novel, she has her own side story chronicled during the events of the High Priest's rampage in Academy City as she tries to deliver the liquid diamond that her parents worked hard on while being chased by Kenzan Shouji and his friends wanting it for themselves. In her adventure, she would cross paths with several other established characters in the series. She is later reintroduced as a recurring character.
Akikawa Mie has shoulder-length black hair and a healthy tan. She wears a white long-sleeved sailor uniform, a shorter-than-average miniskirt and a mint green cardigan, tied around her waist by the sleeves.
Mie acts as a stereotypical teenager, having conflicting feelings like wanting to assert herself via her appearance but not wanting anyone to notice and point it out to her, as well as being embarrassed of her own father. Regardless of this she loves her parents and the work that they do even if she doesn't understand it herself. And from that stems a stubborn determination that led to her smuggling the liquid diamond for the sake of her mother's work despite her own mother's objections.
At some point in the past, Mie became acquainted Keshouin Asuka through her school's tutoring system and formed a friendship with her. Around summer in the current year, the two had promised to go to a Lunar Development Forum together but Asuka came down with a fever and Mie looked after her instead.
Shinyaku Toaru Majutsu no Index
Magic God Invasion Arc
- Main article: Magic God Invasion Arc
Akikawa Mie is in one of the buildings that High Priest threw at Misaka Mikoto, who was able to save it and its occupants using her electromagnetic powers. She was there because she wanted to skip the Anti-Crime Orientation, but was later tasked by her mother to go to the aforementioned building so that she may bring her father his lunch. She later finds herself and the entire building upside down, though she is unscathed thanks to Mikoto's efforts.
Traversing the upside down building she comes upon her father apologizing to his boss about what had happened despite being beyond his control, much to her chagrin. She later tries to leave the building while talking to her mother on the phone. Here her mother talks about the qualities of Mie's father to her as well as the vaults that her father builds for her liquid diamond. After hanging up with her mother she comes upon one of the vaults that his father built that has been crushed after High Priest's rampage. Already worried about the liquid diamond that both her mother and father had worked on, her fears becomes exacerbated once she relies someone is out to steal them. They are Kenzan Shouji and his friends. She quickly takes the storage tube of the liquid diamond and makes a run for it, alerting her presence to Shouji and the others. Thus her journey to take the liquid diamond to her mother begins with Shouji and his friends on her tail believing she is also out to steal it.
As she continues trying to get to her mother, she has a conversation with her over the phone. Her phone tells her to abandon the liquid diamond because it was too dangerous for her and that her company could easily track it down, but Mie is adamant about her decision, surprising her mother. After hanging up she comes into a subway station, bumping into several familiar characters, paranoid of everyone's intentions. When she notices that a girl is sensing that there is something valuable nearby, Mie concludes that she must be referring to the container of the liquid diamond transmitting something. She desperately tries to scrape the writing on the container, in the baseless hope that she won't get tracked down.
Still paranoid, when the train stopped because of High Priest's attacks in one of School District 5's transformer substations, Mie bumps into Hattori Hanzou and Kuruwa. She later flees the train despite the power still not being up, bumping into Shirai Kuroko along the way. Her running doesn't get her far however as her worst fears come to fruition. Kenzan Shouji and his friends later catch up to her, forcing her to give the liquid diamond. Unfortunately for them Kamijou Touma was nearby, and seeing her plight, decides to save her despite being chased by the High Priest. Touma plows the Acrobike into Shouji, allowing Mie to take back the Liquid Diamond container. Touma tells Mie to hold on to the container and get down as he pedals away. Immediately afterwards the High Priest passes through, still trying to catch up to Touma. This allows Mie to escape with the Liquid Diamond, thinking that the High Priest was her savor.
When she arrives at her mother's company, she is met by her mother, embracing her and telling that everything is going to be all right. Here, she witnesses first hand the teamwork and unity of the citizens of Academy City to avert disaster, including her own father. A fact that Kamijou Touma believed and relied on in order to avert the disaster that would happen when the High Priest decided to take the dirt from under Academy City. This however was under the manipulations of Kihara Noukan, making calculations and sending out bait like the liquid diamond that Mie took to prevent human casualties during the High Priest's rampage.
Despite the city being saved from collapsing, Mie herself was not saved from danger. All of a sudden, Kenzan Shouji arrives and points a gun at her, demanding her to give him the Liquid Diamond. With his finger on the trigger, Higata Akio, one of his accomplices, finally had enough of him and hits him with a metal pipe. This distracts Shouji long enough for Mie's father and Shiosai, the man whose gun they stole, to knock him out. Shiosai then cuffs him. Mie asks Akio why he attacked Shouji afterwards, to which Akio says that it was a better alternative than him becoming a murderer.
- Main article: Salome Arc
Mie returns the next day to find out that the student body of A Certain High School will make use of their large campus after their school got destroyed by High Priest. Here, she constantly tries to have Touma remember that he saved her during her flight with the Liquid Diamond incident, though he does not recall, much to her chagrin. As a close friend of Keshouin Asuka, she knows how exactly she acts around various situations. This becomes useful when she and Asuka find Touma being carried by a recently armless Salome. Asuka tries to bribe Salome with a piece of food that Mie made for her in order to protect her, to which Mie becomes suspicious, as she knows she would rather protect the food that Mie made for her as well. As the day continues, she becomes more and more suspicious, eventually confronting her at the school's incinerator. There, she confirms that Asuka is not the same one she knows. Knowing that no one would believe her, she asks for Touma's help as she is aware of the unusual things that happen to him, though her first choice was Kamisato Kakeru.
After explaining the situation, Touma and Salome believe that Kakeru has been manipulated by his faction into acting in the gruesome act of shoving Asuka into the incinerator, having her be replaced by someone else, and having Touma's friends try to use it so that he can use it against Touma. They later confront Touma's friends about what they are doing, eventually forcing Salome to destroy the incinerator only to find that it is empty. Mie does not believe that she was mistaken with Asuka, and is later proven right when after Kakeru denies to Touma and Salome that he had done something to Asuka, Kihara Yuiitsu shows herself before them. Here, she used the FIVE_Over (Out_Sider) - Modelcase_"MENTAL_OUT to disguise herself as Asuka and monitor Kakeru in the hopes of getting her revenge on him for killing Kihara Noukan.
- Main article: Element Arc
Mie becomes an unlikely leader of her school after the Elements and the heatwave struck Academy City, putting it in a standstill. After Touma comes to from battling an Element, Mie has Keshouin Asuka summon him to the student council room as he has become the de facto face of the high school students that have transferred to their school. After Mie notes that they don't have enough water, Fukiyose Seiri begins arguing with Mie over Seiri and the other transfer students' roles in the school, concerned for the animosity and division being created between the two groups. Mie plans to prevent this by having Touma's group secretly seen as "heroes" by having them get a special type of mud that has microbes that eat bacteria to purify the school's swimming pool. For this the group must venture out and retrieve it from School District 7's water department. Seiri is suspicious of Mie's intentions but Touma reassures her that Mie is a good person even if the thought of her "using them" passed her mind as he says that Mie isn't shrewd and would not succumb to emotion.
Kamisato Rescue Arc
- Main article: Kamisato Rescue Arc
- One of the gyarus that approached Saten and Uiharu bears a resemblance to Akikawa Mie, most notably her short hair and cardigan tied around her waist.
- (To her mother as she carries the Liquid Diamond, from NT Index 13): "But that will still mean it was stolen and that’s enough to hurt you and dad. It’ll hurt the path you’ve proudly walked down!"
- Shinyaku Toaru Majutsu no Index Light Novel Volume 13 Chapter 2 Part 4
- Shinyaku Toaru Majutsu no Index Light Novel Volume 13 Chapter 2 Part 9
- Shinyaku Toaru Majutsu no Index Light Novel Volume 15 Chapter 2 Part 5
- Shinyaku Toaru Majutsu no Index Light Novel Volume 13 Chapter 3 Part 1
- Shinyaku Toaru Majutsu no Index Light Novel Volume 13 Chapter 3 Part 4
- Shinyaku Toaru Majutsu no Index Light Novel Volume 13 Chapter 4 Part 2
- Shinyaku Toaru Majutsu no Index Light Novel Volume 13 Chapter 4 Part 11
- Shinyaku Toaru Majutsu no Index Light Novel Volume 15 Chapter 1
- Shinyaku Toaru Majutsu no Index Light Novel Volume 15 Chapter 2
- Shinyaku Toaru Majutsu no Index Light Novel Volume 15 Chapter 3
- Shinyaku Toaru Majutsu no Index Light Novel Volume 15 Chapter 4 Part 1
- Shinyaku Toaru Majutsu no Index Light Novel Volume 15 Chapter 4 Part 4
- Shinyaku Toaru Majutsu no Index Light Novel Volume 16 Chapter 1 Part 1
- Shinyaku Toaru Majutsu no Index Light Novel Volume 17 Epilogue
- Toaru Kagaku no Railgun Manga Chapter 097
|Keshouin Asuka||Glasses Boy||Kamisato Kakeru|