World Egg

The concept of a Reality Marble (固有結界
, Koyū Kekkai
Riariti Māburu
?, Innate Bounded Field) is one that centres around the materialization and projection of one's inner world onto reality following the Thaumaturgical Theory World Egg (世界卵, Sekai Tamago?).[1] Originally, it was an ability specifically had by daemons as their Alien Common Sense (異界常識, Ikai Jōshiki?), but has since come to include the unique Bounded Fields possessed by many people, such as the Twenty-seven Dead Apostle Ancestors and the greatest of magi who have made this ability available to use through a long time. As such, Reality Marbles represent the pinnacle of all Bounded Fields where the boundary line becomes the space itself.

The created worlds are completely cut off from normal reality, projecting their internal landscape and sealing off the regular World. Following the World Egg theory, the actualization of a Reality Marble is the result of switching the Self and the World while keeping the boundary the same. The size of the Self and the World is switched, enclosing the World in a small container while the Self is expanded. The contained World is the World Egg and the name of the theory. They will encase anyone within range, causing them to disappear from view. Magi are still able to feel the presence of the Bounded Field, and while they cannot be directly affected from the outside, a large burst of mana, such as Excalibur, may be able to disrupt them. The World constantly attempts to crush the unnatural bounded fields as they are not created by spiritual beings, meaning that it costs a great deal of magical energy to construct one and keep it stabilized. This generally only allows them to be used for a few minutes, but given their powerful nature, that is likely enough time to properly utilize them; even the strongest Dead Apostle cannot maintain a Reality Marble for more than a single night. Each world has its own set of patterns and rules, which can be said to be an invasion of reality by the diagram inscribed on the soul, and as it is just one aspect put into form, the user cannot add their own will into the form of the barrier.[2]

The practitioners can also make use of certain aspects of their Reality Marbles without activating them. Unlimited Blade Works is responsible for the Projection and Reinforcement abilities of its practitioners, and Rider is able to summon a single soldier from Ionioi Hetairoi at any time without bringing about the corrective impulses of the World. Some can be activated inside the body of the user, such as Unlimited Blade Works going out of control and creating swords inside of Shirou Emiya, and in a special case, Nrvnqsr Chaos only deploys his Reality Marble inside his own body, which allows him to avoid the corrective impulses of the World.

If two Reality Marbles are deployed at the same time, the stronger one will manifests. If both are at the same level, it becomes a "battle between two worlds;" in which both are deployed and one can defend in their Reality Marble or travel to the other.

The mechanics of a Reality Marble being activated when one is already established is unknown. Within SE.RA.PH of the Moon Cell, all areas are manifested as Reality Marbles, and they can be overwritten by those of Servants. Within Fate/EXTRA CCC, Archer's Unlimited Blade Works can be overwritten by Archer's own Unlimited Blade Works, Caster's Eightfold Blessing of Amaterasu, and Saber's Aestus Domus Aurea. It is unknown if this reflects an actual occurrence or if it is limited to a gameplay feature.

It is the closest magecraft to real Magics, a taboo among taboos, mystery among mysteries and one of the pinnacles for magi, so researches on it have been banned by the Mage's Association.[3][4] Obtaining a Reality Marble is not something every magus can achieve through research. Even Caster, far above all modern magi, can only construct "another world" of the same scale with enough time and expenses instead of a Reality Marble.[5] While obtaining a Reality Marble is very hard, a user can pass his Reality Marble down in some way once he gets it.[6]

In the case of Servants utilizing a Reality Marble, it will generally be limited to the Caster class due to the spell's nature as high thaumaturgy, but there are exceptions like Rider.[7] Those of the Berserker class will likely never be able to utilize them, meaning that most who use them will be powerful magi with low combat abilities.[8][9]

Reality Marbles and Marble Phantasm are both ways to create another world, but Reality Marbles turn everything into their own world that even its users cannot change, whereas Marble Phantasm manipulates only natural things as its users want. In other words, both ways have good and bad points.[2] Areas filled with grudges and remnants of strong regrets are like Reality Marbles to spirits.[10]

List of known Reality MarblesEdit

List of known abilities similar to Reality MarblesEdit


  1. 2.0 2.1
  2. Fate/stay night Prologue - Day 2

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