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Otonari Hibiku (音鳴響句 Otonari Hibiku?) is a second-year student of Tokiwadai Middle School and a member of school's health committee,[1] who appears in Toaru Kagaku no Mental Out: The Queen's Play.[2][3][4][5][1][6][7]


Otonari has shoulder-length, wavy red hair.[1] As a Tokiwadai student, she wears the school's uniform.[1]


Otonari is dedicted to what she believes to be her duty as a member of the health committee, as well as her method of stress relief through internal bleeding which believed would ease suffering, described by some others as a 'benevolent violence'. While acting indirectly without intentionally showing herself to her victims, she is willing to barge in and inflict this treatment upon people without permission based on her assumptions and will stubbornly try to 'help' those she deems to be suffering, harming them and those in her way in the process.[3][4][1][6][7]


Otonari's background is largely unknown, but she was in her second year and had a place on Tokiwadai's health committee late in the main story's first year.[2][4]


Toaru Kagaku no Mental Out: The Queen's Play[]

Main article: Toaru Kagaku no Mental Out: The Queen's Play

At some point prior to being among the second-year group assigned to perform A Midsummer Night's Dream in their joint drama class, Otonari had been using her ability to cause internal bleeding in various students, in an effort to relieve their stress via blood loss ecstasy.[4][3] The theory she was following was based on a biological interpretation of vampire stories of victims experiencing pleasure when their blood is drained, that if blood is rapidly removed without triggering a person's sense of pain, the process creates an illusion of feeling good. Willing victims had been leaving signs for her, with at least nine girls known to have fainted as a result and Judgment subsequently investigating the case.[3] She had been interviewed as part of Judgment's investigations and had left something slip that only the perpetrator would know, but they hadn't connected it at the time.[3][1]

The Sunday after the assignment, on learning about Shokuhou Misaki accompanying Kamijou Touma to help prepare for a male role and assuming that she would be stressed at wasting her weekend with an 'uncouth boy', Otonari decided to target her in a misguided attempt to 'help'.[4][6][7] However, she mistakenly linked to Kobayashi Satori who had disguised herself as Shokuhou as an insisted precaution for Shokuhou's safety during the outing.[4][1] While she managed to bring Kobayashi down via Mind Anaphylaxis, Kobayashi in turn brought her down by using her own Telepathy to flood Otonari's mind with verbalized surface-level thoughts of the many people with range.[1][6] Though injured, Otonari put her remaining strength into one final attempt at Shokuhou, but her attack (and her spirit) was crushed by the oblivious Touma's Imagine Breaker, after which she fell unconscious.[7]


Otonari's ability is Level 4 Mind Anaphylaxis (爆雷念話マインドアナフィラキシー Bakurai Nenwa (Maindoanafirakishī)?),[1] a variant of Telepathy.[4] As implied by the name, Otonari manages her power by envisioning it in the form of an allergic reaction. Similar to how forcibly exposing someone with a severe allergy to the matching allergen can produce a lethal reaction, with a theoretical idea of an attack by implanting a fictional allergy inside a target before exposing them, Otonari's ability can mentally implant and induce a similarly damaging reaction.[6]

In order to activate Mind Anaphylaxis's full attack, Otonari needs to carry out three steps.[1] First, she must link to her target's mind.[4][1] Otonari's telepathy links herself to others by "sharing their presence",[4] and although she physically targets her ability,[5] as long as she can sense a target's presence, she can achieve a link even if she cannot see her target.[4] In the case of her attacks, this telepathic link is a forcibly established one-way link,[4] and in the case with Shokuhou and Kobayashi, she was initially applying noise (using the wind direction value as an encryption key) to mask her thoughts, though this mask was removed once Kobayashi established a counter-link.[4]

The second step after the link is established is the process of implanting a trauma or phobia into the target.[1] While the full causes of phobias are not entirely known, they are said to be a mental overreaction resulting from mistaken accumulations of experiences (e.g. through pain, suffering and failure), and this learning process can be artificially applied through telepathy.[1] Otonari does this by sending over 20,000 telepathic messages a second, transmitting a massive amount of compressed information into the target's brain where it sticks.[1] In addition to giving a target a new phobia through this method, regardless of whatever phobias they already have or don't have, Otonari can apparently create fictional phobias not present in medical literature.[1]

Finally, the trauma must be physically triggered from outside to damage their mind.[1][6] In the case of Kobayashi Satori, Otonari implanted gynophobia that would be triggered by her own body.[1][6]

Aside from her ability, Otonari has received Tokiwadai's training in basic self-defense techniques.[1]



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Tokiwadai Middle School
Students (Current Year)
Misaka Shirai Kuroko Winter Clothing (Anime) Shokuhou Misaki in Winter Clothing (Anime) Hokaze Junko Winter Clothing (Anime) Kongou Mitsuko in Winter Clothing (Anime)
Misaka Mikoto[1] Shirai Kuroko Shokuhou Misaki[1] Hokaze Junko[1] Kongou Mitsuko
Awatsuki Maaya RailgunT (Anime) Wannai Kinuho RailgunT (Anime) Kirifu Megumi (Anime) Kobayashi Satori (Anime) Yumiya Iruka Color (Astral Buddy)
Awatsuki Maaya Wannai Kinuho Kirifu Megumi[1] Kobayashi Satori[1] Yumiya Iruka
Houjou Arei (Astral Buddy) Makigami Komaki (Astral Buddy) Maybe Natsumi Sakibasu Yuri (Navbox) Gaouin Tsukasa
Houjou Arei Makigami Komaki Natsumi Sakibasu Yuri Gaouin Tsukasa
Kamino Kokuchou Mayui Iori Mashiro Tatsuki Mirei Kumamori Tazuna
Kamino Kokuchou Mayui Iori Mashiro Tatsuki Mirei Kumamori Tazuna
Inubushi Glasses Judgment Girl - Commissioner (Mental Out) Mei (Anime) Kii (Anime) Resanerié Sadis Dialine
Inubushi Glasses Judgment Girl Mei Kii Resanerié Sadis Dialine[1]
Asato Kisa (Anime) Mibuki Kazan (Anime) Spy in Shokuhou Clique Otonari Hibiku
Asato Kisa[1] Mibuki Kazan[1] Nenohi Wakana Otonari Hibiku
AndouIkushimaInoriKinoshita HagoromoMatsuzai ShoukoSenbayashi KonomiTanaka MizuhoUmibe RyoukoUsukinu YasumiYonaki ReikaYamashiroYanagisakiin RondoYugure Kanaria
[1]: Student who is also present in Tokiwadai 1 year ago.
Students (1 Year Ago)
Kessai Kiyoshi (Navbox) Shinenkouji Rurikakesu Sha Tanshan Mikagami Nagisa Hasekura Reiri
Kessai Kiyoshi[C] Shin'enkouji Rurikakesu[G] Sha Danshan[C] Mikagami Nagisa[G] Hasekura Reiri[G]
Lily Ouyang Qian Lin Lihua Urui Aika Kazanin Tsukasa
Wu Lili Ouyang Qian Lin Lihua Urui Aika[G] Kazan'in Tsukasa[G]
Asakura Olivia Moa Kadosaka Rina Sukezawa Sena Enjou Kasumi Yasutoba Suika
Asakura Olivia Moa[G] Kadosaka Rina Sukezawa Sena Enjou Kasumi Yasutoba Suika[G]
Amano Ayane Unnamed Hasekura Clique Member 1 (Railgun Ch139) Unnamed Hasekura Clique Member 2 (Railgun Ch138) Unnamed Hasekura Clique Member 3 (Railgun Ch138) Ibotanokikouji Kaede
Amano Ayane[G] Satsuki Mahiru Soyogo Kato Asuwara Yui Ibotanokikouji Kaede[D][F]
For the unnamed clique members, see respective pages: Sha Clique, Mikagami Clique, and Hasekura Clique.
[C]: Student who is present in current year. / [D]: Deceased / [F]: Former student who haven't graduated but left school / [G]: Graduated
Students (2 Years Ago and Earlier)
Takebayashi Yayoi
Takebayashi Yayoi[D][F]
[D]: Deceased / [F]: Former student who haven't graduated but left school
Unabara (Mental Out Ch20, 6D+6F) Ryoukan Watanabe (Anime)
Director Unabara
Tokiwadai Dorm Supervisor Watanabe