World Egg.jpg

The concept of a Reality Marble (固有結界(リアリティ・マーブル), 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,[2][3] 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.[2] 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,[4] 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.[1] 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,[2] 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.[5] 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.[2]

When two Reality Marbles are deployed the one with higher output (magic foundation, magical energy) would be deployed. If both parties are equal in power and successfully deploy their Reality Marble, they would enter a state of two worlds in conflict. Reality Marbles do not move from the place they were deployed at (they don't move along with the user), so the user would have to decide whether to draw the enemy into their own world, invade their opponent's world to crush them, or wait for both to run out of time and go back to fighting on neutral grounds.[6]

Within SE.RA.PH of the Moon Cell, all areas are manifested as Reality Marbles,[7] 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.[2][3][8] That said, Reality Marbles are also considered magecraft, a series of taken tricks to deceive the world, taken to its logical extreme.[9] But 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.[10] While obtaining a Reality Marble is very hard, a user can pass his Reality Marble down in some way once he gets it.[11]

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.[12] 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.[13][14]

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.[15]

List of known Reality Marbles[]

User Name Notes
Einnashe Unknown
Kingprotea Airavata King Size

List of known abilities similar to Reality Marbles[]


  1. 1.0 1.1
    [v] Fate/complete material III: World material - Theory of Magic - Magecraft: Reality Marble, p.045

    Reality Marble
    A Reality Marble is magic that actualizes the internal landscape of oneself. If it's activated, the surrounding space is changed to a completely different landscape.
    The actualization of the internal landscape will be explained by the magical theory, "World Egg" shown in the figures to the bottom left.
    That is, the Reality Marble is the result of switching the Self and the World while keeping the boundary the same. At this time, the size of the Self and the World is switched, and the World is enclosed in a little container. This little World is the World egg and the name of the theory.

  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6
    [v] Tsukihime Dokuhon PlusPeriod - TSUKIHIME Dictionary: Reality Marble [Unusual talent], p.179

    Reality Marble [Unusual talent]
    Intrinsic Field.
    Originally referred to the alien common sense possessed by the beings called devils, but now also includes the unique boundary fields possessed by many people.
    A subset of marble phantasm, it erodes reality and gives form to the user's imagined world. It is the sorcery closest to magic, and a forbidden art within the Association.
    Unlike marble phantasm, however, the form of a reality marble cannot be freely adjusted. It is the manifestation of the user's one-and-only self, after all, so changing it with their will is impossible. On the other hand, since even things that are not part of nature can be influenced, perhaps it is actually even more amazing than marble phantasm, in a way.
    Marble phantasm, which can change the world at will, but only has influence over elementals and nature. Reality marbles, which are limited in use to a single pattern, but force everything to submit to the user's personal rules. Though the methods are different and they are each limited in their own way, the fact remains that they are both powerful abilities that change the world.
    …Properly speaking, reality marbles are only supposed to be used by elementals and devils, but given enough time it is possible for some advanced practitioners to complete a sorcery to give shape to their personal imagined world and create a reality marble of their own.
    Of course, if anything that isn't an extension of nature like an elemental creates an alien world, the world itself will crush it. As a result, the upkeep of a reality marble requires a vast amount of energy, and most individuals are only capable of using one for a few minutes at a time.
    Most of the 27 Dead Apostle Ancestors are capable of using reality marbles. Oh, and Nrvnqsr was able to escape the corrective influence of the world by using his reality marble within his own body. Way to go, Professor Chaos.


  3. 3.0 3.1
    [v] Melty Blood Act Cadenza PS2 Manual - Dictionary: Reality Marble [Unusual talent], p.056

    Reality Marble [Unusual talent]
    Intrinsic Field. Originally referred to the alien common sense possessed by the beings called devils, but now also includes the unique boundary fields possessed by many people.
    A subset of marble phantasm, it erodes reality and gives form to the user's imagined world. It is the sorcery closest to magic, and a forbidden art within the Association.


  4. Fate/stay night- Heaven's Feel route - Day 15: limited. - Nine Bullet Revolver
  5. Melty Blood Block D: 3/Fierce Heat, With Scattered Lies - Alice's Anxiety
  6. FGO's 5th Anniversary Famitsu Q&A

    Q: There are multiple characters with Reality Marbles in FGO. What happens if they use them at the same time?

    Nasu: If the opponent’s output is higher, a Reality Marble can’t be used. If both are equal and use them at the same time, I think the two worlds would resist each other. As the RM does not move from the position it is used (does not move with the user), the users have to decide whether to draw the opponent in, step into the opponent’s world, or just wait until both RMs die out.

  7. Fate/EXTRA- Archer route - Week 1 Day 4
  8. Reality Marble dictionary entry

    Reality Marble
    A Magecraft close to Sorcery. A taboo among taboos, a mystery among mysteries. One of the pinnacles for a magus.


  9. The Adventures of Lord El-Melloi II Volume 2: The Devil of the Wandering Sea (Upper) - Chapter 2
  10. [v] Comptiq 2007-04 issue - Fate Dojo Q & A:
    Q: Although it did not appear in the works, can Caster use a Reality Marble?

    Q: Although it did not appear in the works, can Caster use a Reality Marble?

    A: Unfortunately, Caster cannot use it. But, if it is a magus of her level of excellence, by precisely constructing small magecraft and large magecraft, she can construct "another world" of the same scale, don't you agree? Well, the time and expenses required for that is vast, after all.


    A:残念ながら使えません。が、彼女ほど超絶した魔術師なら、小さな魔術と大きな魔術を緻密に構築していく事で同規模の「異界」を作り上げられる でしょう。まあ、その為にかかる時間と費用はやっぱり莫大なものですが。

  11. Toraburu Hanafuda Travel Journal Normal Mode - Kirei Kotomine, Gilgamesh and Lancer Route - Final Stage

    Buruma : Fufu, do you know this? Reality Marbles can be passed down.

    ブルマ:ふふ、知ってる? 固有結界って継承できるのよ?

  12. Fate/Zero Volume 2: The Mad Feast of Kings - Act 8 Part 6 -102:54:10

    “How could this be….you could materialize the environment inside your mind…You aren’t a – magus?!”

    “Of course I’m not. This is not something I can do alone.”

  13. Fate/EXTRA - Touko Aozaki conversation

    "A Berserker? Are you sure you aren't mistaken? This Servant is using a large-scale reality marble, right? That's not a Berserker's style. A reality marble is highly advanced thaumaturgy. So if you think about it, a Caster makes more sense. …I'm sure there's more to the story, though."

  14. Fate/EXTRA - Female Student conversation

    Female Student:
    If you're talking about reality marbles, you won't see that many Servants using them. That Servant must be powerful to use a reality marble. The Master too, for that matter

  15. Fate/stay night Prologue - Day 2