Reading Thoth 78 (問答型思考補助式人工知能 (リーディングトート78) Mondō-Gata Shikō Hojo-Shiki Jinkō-Chinō (Rīdingu Tōto 78)?, lit. "Discussion-type Thought Assistance Artificial Intelligence") is a parallel processing device and artificial intelligence built into the Windowless Building that is introduced in Shinyaku Toaru Majutsu no Index that is apparently for the sole purpose of being used by Aleister Crowley.


The name is derived from the Thoth Tarot that was created by Aleister Crowley. The deck is named after the Egyptian deity Thoth. The number 78 is the number of all the cards of the Tarot according to Gematria, and coincidentally, is also the number that was first attributed to AIVAS, or Aiwass.


The AI can apparently recognize Aleister Crowley through his biometrics, and refers to him as "Aleister-sama". As its name suggests, it apparently not only reports information, but apparently discusses it with the user, giving metaphors to help the user to better understand the topic like a human. Moreover, when there is a different topic that the AI deem necessary, it makes a link to that topic. It also has calculation and estimating type abilities like a normal computer.[1]

Reading Thoth 78 is capable of verifying certain calculations such as those carried out by Tree Diagram,[2][3] and is capable of simulating and manifesting recreations of certain individuals, together with their personality and a degree of their abilities, such as with Mina Mathers.[2]

The core of the Reading Thoth 78 is made up of the 78 Tarot cards constructed by Aleister, which can also be seen as sorting them all into a single book. As such, it is also the original grimoire known as the Thoth Tarot (トートタロット Tōto Tarotto?). As a grimoire, the Thoth Tarot is capable of absorbing power from its surroundings, enabling it to automatically use magic for self-defense, despite being unable to refine magic power as a living being can. Additionally, it contains the essence of the Holy Guardian Angel Aiwass and through the 20th card of the Major Arcana, 'The Aeon', is capable of drawing on Aiwass's power.[2] Incorporating the Thoth Tarot into the digital parallel processing device and forming a grimoire in this way had the accidental effect of creating a thought entity, which would be given the recreated identity of Mina Mathers.[4]

The main Reading Thoth 78 is built into the Windowless Building,[2] however Aleister has created a version of the AI reduced to a consumer level, Aneri, and spread it through Academy City.[3]


Shinyaku Toaru Majutsu no IndexEdit

Ichihanaran Festival ArcEdit

Main article: Ichihanaran Festival Arc

The technology appears after some time Fräulein Kreutune has escaped the Windowless Building. Here, it apparently welcomes Aleister Crowley back and begins discussing the existence known as Fräulein Kreutune, who she is, what she is capable of, and what she will do, estimating that Fräulein will acquire properties that allows her to eat and absorb brains, will begin within two hours after its conclusion.[1]

Aleister Crowley ArcEdit

Main article: Aleister Crowley Arc

On December 11th, when Kamijou Touma's group entered the Windowless Building, the Reading Thoth 78, using the form of Mina Mathers, guided Touma through a series of visions detailing Aleister's past,[5] and later assisted him against Aleister and Aiwass.[2]

Processor Suit ArcEdit

Main article: Processor Suit Arc

When the Windowless Building was launched into space in order to delay Coronzon, the Reading Thoth 78's recreation of Mina Mathers acted to prevent the demon from escaping. Aiwass then intervened and created a new grimoire derived from the Thoth Tarot to sustain her existence in place of the processing device, freeing her from the bounds of the Windowless Building.[4] While Mina Mathers escaped to Academy City and survived thanks to the new grimoire,[6][7] the original processing device was smashed to pieces along with the Windowless Building when it crashed into the 'new world' version of Academy City.[8]


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