Fate: What are Magic Circuits?

Fate What are Magic Circuits

The lore and magic system is extraordinarily developed and intricately detailed to the point that it could be overwhelming to certain fans, especially newcomers to the franchise. There are so many different terminologies related to the ‘Mystery’ system of Fate and Magic Circuits are one of the most important concepts involved. But what are Magic Circuits? Let’s find out.

What are Magic Circuits?

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A Magic Circuit is a pseudo-nervous system that spreads across the human body, the existence of which qualifies a human to be a Magus. They exist to assist the user in the conversion of Life Force into Magical Energy while also providing them access to Greater Magic Formulae, often called Thaumaturgical Foundations that allow them to perform Magecraft.

Magic Circuits are also responsible for connecting the Material World to the Astral Plane. In order to wield Mysteries, a Magus transmits instructions and Magical Energy through their Magic Circuits to a Thaumaturgical Foundation, effectively triggering one of the Magic Formulae contained within the Foundation.

Passing down Circuits

One’s Magic Circuits are determined at birth and cannot be increased or decreased without unnatural means, just like any other organ in the body. Due to this, lineages of the Magi who have a deep-rooted history in Magecraft across generations are often considered to be more powerful.

  • Magi usually don’t tamper with existing Magic Circuits but rather try to produce descendants with the greatest “extra” number of Magic Circuits possible.
  • To artificially increase one’s Magic Circuits, a ‘Mystic Pass’ is performed between two Magi, allowing for the transfer of these Circuits. Since the Magic Circuits reside in the soul, a fusion of the body and mind is necessary for successful transplantation.

However, this procedure entails risks and complications akin to those of an organ transplant. Additionally, if the Magic Circuits are tampered with while in operation, they may become unstable, potentially leading to mutual destruction unless a prior contract similar to that between a Magus and their Familiar has been established.

Interactions with the Human Body

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  • Magic Circuits are fundamentally unnatural for the human body, causing discomfort and numbing sensations for the Magus when activated. Additionally, the activation of Magic Circuits raises the Magus’ body temperature.
  • Kiritsugu Emiya used this gimmick to detect enemy Masters on the battlefield during the Fourth Grail War using a thermal sensor.

Magical Circuits ‘Open’ when Magical Energy runs through the body for the first time. A Magus creates their own personal mental trigger based on their initial experience, allowing them to subsequently activate their Magic Circuits at will. As a result, these triggers vary from person to person, ranging anywhere from self-injury to sexual excitement. (The latter of which is the case for a surprisingly large number of Magi.)


Ultimately, Magic Circuits form the foundations of Magecraft performed by humans in the Fate universe and all concepts used by humans are derivative of it in some way, shape, or form. As a lesser-known feature, they are also capable of storing or recording information. However, Magic Circuits are constant and can never be ‘changed’, meaning that they can’t be repaired if damaged.


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