Aisa's family name Himegami is an aptronym for her, as it is basically read as the characters (姫 and 髪), meaning Princess and Hair respectively, referring to the hime cut, a hairstyle that Aisa sports.
Aisa looks like a normal teenage girl. She has long, straight, black hair, and is often seen wearing her miko outfit. After the events of the second volume, she begins wearing a cross necklace given to her by Necessarius so vampires will not be attracted to her blood.
She is a quiet, young girl with a rather blunt personality, generally soft-spoken and sometimes shy. She can be as gluttonous as Index , which is shown when she was trying to buy out all hamburgers at one restaurant. Because of her ability, she has been miserable because her friends and family were killed by it. Ever since Touma saved her life, Aisa started to have feelings for him, which is ironic as she once joked that Touma's life was like a dating sim.
She also has a kind and considerate side, shown during the Daihaseisai after she was recovering from the near-fatal injury caused by Oriana Thomson, she once thought about leaving Touma and everyone else since she seems to only be a burden to Touma. She thought she didn't have any special talents that could help Touma, nor was she the kind of person that could help others just by her presence like Index. Though Index quickly told her it wasn't true, as Himegami is everyone's friend and a valuable person to everyone who was worth saving .
One of her strongest personality traits is a slight complex about not being special, she can usually be seen reading books with advice on how to rebuild yourself or how to increase your own individuality; Touma once noticed that as she is very talented when cooking she has an important distinctive feature , however Aisa realizes that such trait it's not enough individuality when faced to the unique characters that are around her, such as Tsukuyomi Komoe. Due to the events that have occurred in her past, her initial goal of wanting to be a magician of fairy tales and picture books because she wanted to save those that can't be saved.
Touma also has pointed out that even though she is really quiet, it's not like she doesn't want to express herself, and as such many of the things that she wants to say are showed in some other way even if it's almost impossible to perceive normally, the example that Touma used was that when Himegami is happy she doesn't say anything, but she slightly curls up her lips to show that feeling. 
According to Kamachi Kazuma, he created Aisa as a tragic girl who can never be the female protagonist. That may explain why both in canon and in the fandom, she is barely notable and is the target of constant jokes of her irrelevance.
Known as "Deep Blood," she has the ability to attract and kill vampires. Ten years prior to the start of the series, Aisa lived in a mountain village in Kyoto. Here, a vampire, fearing the power that Aisa held, turned everyone in the village into vampires as a reaction to it. Predictably, they were drawn to her blood and bit, turning to dust. Even the vampire became a victim at some unknown point.
This incident prompts her to go to Academy City, hoping to find a way to get rid of her power and not kill anyone anymore. She arrives in Academy City to find a way to a way to know the secret of her power, and by proxy find the way to remove it. Enrolling in Kirigaoka Girls' Academy, Aisa discovers that even Academy City itself couldn't give her answers. She is later kidnapped by the Cult of Science and taken into Misawa Cram School, imprisoning and apparently abusing her there. Later, Aureolus Izzard later takes over and controls the school, freeing her from imprisonment. Aureolus, looking for a vampire in his plans to save Index agrees to give Aisa a Walking Church which would seal her powers and free her from its burden if she cooperates and help him draw vampires. She agrees and becomes ecstatic that she finally found a shortcut to her dreams.
Because of her exceptionally rare ability, she is enrolled into Kirigaoka Girls' Academy. She later discovers of the apparent existence of Kazakiri Hyouka, who always tops the rankings of the school, but no one has ever saw her, which year she was or even her powers. Aisa then asks one of her teachers about Kazakiri Hyouka, and discovers that she is called Counter Stop, more importantly, she is called the Key to the Imaginary Number District, and a special lab was set up just to investigate her. It is later revealed that even the teacher she asked has never seen Hyouka, and that her true identity is known only to a few teachers.
Toaru Majutsu no IndexEdit
Deep Blood ArcEdit
- Main article: Deep Blood Arc
Aisa becomes a major concern to the Magic Side as she has been apparently abducted by Aureolus Izzard, a powerful alchemist who has taken over Misawa Cram School and is an enemy of the Roman Catholic Church. With the situation complicating, Stiyl Magnus is recalled back to Academy City to rescue her. Even though Academy City is unable to intervene with the Magic Side's affairs, Aleister Crowley allows Stiyl to borrow Kamijou Touma's help, as he deems him as no threat to the Magic and Science Side's secrets.
Aisa is first seen in Macronall Hamburger, having spent all her money on hamburgers and unable to go home. Touma and Index meet her, where she tries to borrow money from Touma, but is refused and Index argues with her for claiming to be a magician without proof. She is later escorted by teachers of Misawa Cram School, making Touma suspicious.
Touma later realizes, after being involved by Stiyl, that the person they are trying to save is Aisa. Aisa meets Touma again within the confines of the school and tells her the reason why she joined Aureolus.When Aureolus learns Index's life was already saved by Touma and tries to kill him, Aisa attempts to defend Touma, which prompts Aureolus to use his alchemy to try to kill her as she is now useless to him. Her life is saved by Touma who dispels the spell on her with his right hand. When she asks Touma about why he saved her, he told her that he did not have a reason to rescue her. After the incident, she starts to live with Touma and Index but later moves to Tsukuyomi Komoe's Tsukuyomi Residence.
- Main article: Sisters Arc
She is given a British Puritan cross that is able to seal off her ability, which, according to Index, is the bare minimum of what makes up a Walking Church barrier. Because of this, she was highly recommended by Kirigaoka Academy for Girls to transfer schools (kicked-out), and as such lost her dorm, necessitating for her to move with Tsukuyomi Komoe.
During the Sisters Arc, she is first shown trying to find a way to get rid of the fleas on Sphynx, with her suggesting to use an insecticide spray on the cat. When Touma brings Misaka 10032 to his dormitory, she comments on him being a protagonist of a dating sim, and how he raises flags and inevitably gathers girls around him. She is later seen with Komoe and Index, partaking in various activities such as eating and going to a certain bathhouse, while hearing Komoe's explanation on how esper abilities work.
Angel Fall ArcEdit
- Main article: Angel Fall Arc
Due to Angel Fall, her appearance is given to an unknown truck driver who drives Touma back to the island to save his father.
Three Stories ArcEdit
- Main article: Three Stories Arc
In the anime Aisa is seen walking by Julian Restaurant when she gets bumped by an invisible Yamisaka Ouma who at that time had kidnapped Index. This occurs in the novels as well, although Accelerator manages to witness it all.
Kazakiri Hyouka ArcEdit
- Main article: Kazakiri Hyouka Arc
Later, during Sherry Cromwell's attack on the mall, Aisa tries to call Touma on her phone, but is unable to get through although Komoe was able to get through just fine. She and Komoe would later scold Touma in a certain hospital for his reckless behavior.
Daihasei Festival ArcEdit
- Main article: Daihasei Festival Arc
She has a part small part in this arc and when not focusing on the sport events of the festival she is usually seen around Komoe-sensei; she notices that Touma is being restless about something however she cannot understand what's really behind Touma's worries. It is revealed that Himegami and Tsuchimikado Maika have a close friendship when Maika approached the class in order to sell bentos. 
Later on, she and Komoe-sensei bumps into Oriana Thomson, who notices that Aisa dons a Walking Church. Mistaking her for an Index-class pursuer magician Oriana proceeds to attack Aisa and injures her greatly. Touma and Stiyl appear shortly after that and initially they can only feel frustration faced to Himegami's terrible injuries; Komoe is attempting to use the healing magic that she used on Index back in then in Volume 1 but she is unsuccessful on recreating the spell until Stiyl takes over and manages to stabilize Aisa's condition enough for her to be treated by the Frog-Faced doctor.
Aisa spends the rest of the arc in the hospital recuperating. However Index, Seiri, and Touma later drops by to visit her after the conflict finally ends.
Academy City Invasion ArcEdit
- Main article: Academy City Invasion Arc
She briefly appears talking to Fukiyose Seiri and witnessing her knocking out the "idiot trio."
- Main article: Skill-Out Uprising
She appears at the beginning of the arc eating lunch with Touma. After she begins choking, Touma tries to rub her back to help her. Unfortunately, his efforts only cause her bra strap to become accidentally unhooked, and she then punches Touma in the stomach. She later appears while the class is at a restaurant having dinner.
British Royal Family ArcEdit
- Main article: British Royal Family Arc
As Fukiyose Seiri and the 'three class idiots' talk about the upcoming cultural festival in Academy City, known as the largest culture festival in the world, Aisa is reading a book that states a good way to capture another person's heart is to stand out in some way, apparently trying to gain Touma's attention and attraction. Komoe then walks into the class, and Aisa despairs seeing no matter how much traits she has she can never match the numerous amounts of Komoe, being a 135cm height but still a grown woman that chain-smokes and loves beer, specializes in studying pyrokinetic esper abilities, and a expert in AIM fields.
Shinyaku Toaru Majutsu no IndexEdit
- Main article: Homecoming Arc
Aisa sees Touma and asks what he was doing there, with many other girls coming soon after. After she was told by Birdway's men leave Touma alone for the time being, she was later seen talking to Komoe about him, giving her opinion on how Touma not going to class may be a method in defeating a dragon.
Ichihanaran Festival ArcEdit
- Main article: Ichihanaran Festival Arc
Aisa is with her class helping out with the preparations of the Ichihanaransai, when she is asked by Seiri if she knows where Touma is. She, like Mikoto, may have overheard that Touma has been arrested by Anti-Skill after his tussle with Thor.
Magic God Othinus ArcEdit
- Main article: Magic God Othinus Arc
Aisa doesn't appear at all in-text or is even mentioned in passing. She however, appears in the illustration depicting the second recreation of the world by Othinus, known as the Version_Beta world in-text, where another "Kamijou Touma" exists living Touma's life. She is in the background along with Headband girl.
Toaru Kagaku no RailgunEdit
- Main article: Poltergeist Arc
Aisa gets a cameo in episode 17 and is seen ordering all the hamburgers in Macronall Hamburger. Tessou Tsuzuri, a member of Anti-Skill ask her why she wants all the hamburgers, with Aisa answering that she likes their taste. In this episode, it is indicated by Aisa's cross necklace that the Deep Blood Arc has already been concluded. Also, Aisa also states that she is from Kirigaoka Girls' Academy, which would imply that she has yet to enroll in a certain highschool.
In the final episode of the anime, she is seen with Komoe in the epilogue.
Daihasei Festival ArcEdit
- Main article: Daihasei Festival Arc (Railgun)
Prior to the start of the Daihaseisai, she aids Seiri in laying out the route for the upcoming event. Both are seen by Saten Ruiko and Uiharu Kazari, who are passing by. In her brief appearance, Aisa's face is always obstructed by an object.
Dream Ranker ArcEdit
- Main article: Dream Ranker Arc
Himegami Aisa's dream is sold as an Indian Poker card and is visited by Misaka Mikoto. Here, Aisa laments how she doesn't stand out, admiring how Seiri stands out despite being surrounded by unique people, and complaining about her breasts are huge compared to her. Mikoto, who has a meager bust line, is angered by Aisa's complaints and wakes up as a result.
Continuing the gag from her previous appearance, her face is never shown in her short appearance.
Toaru Majutsu no Index-tanEdit
Aisa is first seen in the special in a short parody of the opening theme, here she is seen holding the Palmtop Tiger from the Toradora! series instead of Sphynx. Aisa is later seen with Komoe and Index-tan, in a parody to the scene in the Sisters Arc, where she enjoys the food Komoe cooked for them. Here, she asks Komoe repeatedly that she wants to eat meat, but is ignored by Komoe every time.
The 2nd Toaru Majutsu no Index-tan episode features Aisa in front of chalkboard, trying to say lines to the audience of is always cut-off before finishing a sentence, which may be a reference to her being insignificant and ignored in the storyline. One notable line she would have recited was a line by Enma Ai, the main character of Jigoku Shoujo - while using the character's voice as well, who has the same voice actress (Mamiko Noto) as Aisa.
She appears briefly near the end of the 3rd episode, being made fun out of the fact alongside with Tsukuyomi Komoe, on how she was not even mentioned or played a part in the episode, with a laugh track.
She appears in the 4th episode in a scene parodying her choking in episode 23 of the second season of the anime adaptation. Here, despite Touma trying to get an answer out of her if she was alright after rubbing her back to relieve her, Aisa never gives an answer as Touma's rubbing unhooked her bra. Out of nowhere, Fukiyose Seiri arrives and tells everyone she has a front hook bra, much to Touma and every boy in the class' celebration. Here, Aisa is completely overshadowed by Seiri. In another scene, Aisa once again tries to eat her meat and other food but it keeps getting stolen by Index-tan.
Toaru Majutsu no Index: Love Letter CompetitionEdit
- Main article: Toaru Majutsu no Index: Love Letter Competition
Aisa witnesses to Kumokawa Seria's request to Fukiyose Seiri of delivering a mysterious letter to Touma. She later casually says to Seriri that she has been to Touma's place before.
Toaru Majutsu no Index Movie: Miracle of EndymionEdit
- Main article: Toaru Majutsu no Index Movie: Miracle of Endymion
Aisa appears briefly, overhearing the conversation with Touma, Aogami, and Motoharu, that he couldn't sleep because someone occupied his bed. She was so shocked her hand slipped the bag she was carrying.
Non in-universe appearancesEdit
In Episode 10 of Durarara!! Erika Karisawa and Walker Yumasaki are arguing about who will become the staring heroine of the series with Walker believing it to be Biri-Biri and Erika disagreeing believing it to be Himegami instead, while they are each holding the first volume of the Railgun Manga.
Aisa's ability is called Deep Blood (
She has been trained in and experienced in first aid easily recognizing the damage done to a victim was not a severe as it looked despite the amount of blood and calmly analyzed the scene remaining so although the emergency treatment.
- Stun Baton (電動ガスガン Dendou Gasgun?, lit. Electric Gas Gun) : She has one and prefers to call it her Magical Stick (魔法のステッキ Mahou no Stick?). Officially the electric baton is also known as Head Crush (西瓜割り Suikawari?, lit, Watermelon Splitter) and was banned from sale in Japan in 1993 due to its excessive strength.
Character Art DesignEdit
Due to her standard character design, Haimura had no troubles designing Aisa, though notes that there is an inconsistency in the illustrations regarding the red strings that line the sleeves of Aisa's outfit.
Aisa is affected by Haimura's deformed style change by volume 12, among most characters.
- Himegami first appear in the manga version in Volume 7 in Kazakiri Hyouka and the Imaginary Number Discrict Arc where she came in as a transfer student in A Certain Highschool like in the novel and anime version where Deep Blood Arc did not exist in the manga version and give warning to Touma about Kazakiri Hyouka.
- She is the main character of an omake called "Deep Blood" in the Volume 2 of the manga, where she has to fight against "zombies" using her "Miko Powers". In a very Aisa like fashion, the story end ups with the Editor of the manga calling Kogino Chuuya, ordering him to cut Himegami Aisa's Deep Blood arc, in order to start right away with the Mikoto centric Sisters arc.
- After leaving the Misawa Cram School building, she initially lived with Kamijou Touma's residence (Volume 2), after that she moved to Tsukuyomi Komoe's residence (Volume 3). By the time she enrolls in a certain school she moves to the school dorms (Volume 6).
- She came in last in the Toaru Sakuhin no Convention character poll of the Toaru Kaki no Campaign event.
- (To Touma) "Lend me 100 yen since I'm beautiful."
- (To Index / Touma) "Perhaps, that is his fate. He raises flags with other people and goes down their story routes." -referring to Touma and his ability to attract girls.
- (To Touma) "I'm a girl who goes unnoticed after all, huh?"
- (To Tsuzuri) "Their taste is unforgettable. So I want them all." -referring to hamburgers.
- (To Touma) “Up till now, you looked like you’re about to face a demon king. Why put on a brave warrior look?”
- (To Touma / herself) “A-are you saying…that what I wished for was within me all along…?” --- “My era starts now. I will use magic bentos to put an end to the era where I was the expressionless person shoved to the side…” -- When pointed out that cooking is her very own personal trait.
- ↑ 1.0 1.1 1.2 1.3 Toaru Majutsu no Index Light Novel Volume 03 Chapter 1 Part 3
- ↑ 2.0 2.1 Toaru Majutsu no Index Light Novel Volume 10 Epilogue Part 4
- ↑ Toaru Majutsu no Index Light Novel Volume 17 Chapter 01 Part 3
- ↑ 4.0 4.1 4.2 4.3 Toaru Majutsu no Index Light Novel Volume 02 Between the lines 2
- ↑ Toaru Majutsu no Index Light Novel Volume 02 Afterword
- ↑ 6.0 6.1 Toaru Majutsu no Index Light Novel Volume 02 Chapter 3 Part 2
- ↑ Toaru Majutsu no Index Light Novel Volume 06 Chapter 1 Part 8
- ↑ Toaru Majutsu no Index Light Novel Volume 09 Chapter 02 Part 4
- ↑ Toaru Majutsu no Index Light Novel Volume 17 Chapter 1 Part 3
- ↑ Toaru Majutsu no Index Light Novel Volume 18 Chapter 6 Part 5
- ↑ Shinyaku Toaru Majutsu no Index Light Novel Volume 02 Chapter 1 Part 2
- ↑ Shinyaku Toaru Majutsu no Index Light Novel Volume 02 Chapter 2 Part 1
- ↑ Shinyaku Toaru Majutsu no Index Light Novel Volume 05 Chapter 3 Part 1
- ↑ Toaru Kagaku no Railgun Manga Chapter 079
- ↑ 15.0 15.1 Toaru Majutsu no Index Light Novel Volume 02 Chapter 2 Part 7
|A Certain High School
|Kamijou Touma||Tsuchimikado Motoharu||Aogami Pierce||Kumokawa Seria|
|Himegami Aisa||Fukiyose Seiri||Headband girl||Spiky-haired glasses girl|
|Tsukuyomi Komoe||Yomikawa Aiho||Oyafune Suama||Saigo|
|Himegami Aisa||Sogiita Gunha||Gemstone Girl||White Player|