FGO: What Is Rayshift? (A Current Summary)
[さいごのかぎ] Townmemory's Research Notes Author: Townmemory / First draft: May 24, 2025 [Based on information up through Lostbelt No. 4]
Translator's note: This article is an English translation of a piece originally written in Japanese in May 2025. It is based on information available up through Lostbelt No. 4. Some statements may have been superseded or weakened by subsequent revelations; however, we have chosen to preserve them as written, as we believe it is valuable to show how far the reasoning could reach at the time. The translation was produced with the assistance of AI. The URL of the original Japanese text is as follows: https://penultimatekey.hatenablog.com/entry/2025/05/24/082754
FGO features a mysterious technology called "Rayshift." In a nutshell, it sends a human being instantaneously to a specific location in the past or future. Essentially a time machine.
I've worked through my own understanding of the underlying logic to a point where it feels satisfying enough, so I'm writing it up here.
A related earlier article of mine can be found here: FGO: Continued — Displacement Magic (We Who Become Probabilistic)
■ And Yet, Past-Fujimaru Isn't in the Singularity
Based on how Rayshift is depicted in the story, the procedure goes something like this:
1) Fujimaru is put into a Coffin. 2) Fujimaru undergoes spirit particle conversion (exact nature unclear). 3) Some kind of tunnel-rush effect happens, and Fujimaru appears at a specific time and place.
Just looking at the description, it seems like: "The person inside the Coffin is converted into a state that allows transmission to a different spacetime, and then transmitted." Like the transporter in Star Trek. Or the matter transmitter in The Fly (though I wonder how many readers that reference still reaches).
However, when you sort through the finer details given in-story, it seems like the SF-movie approach — "break the human into tiny particles, blow them through a straw to the destination, and reconstruct the body on-site" — is not what's happening. Because Morgan says: "What can be sent via Rayshift is information only."
(Morgan) What can be sent via Rayshift is information only. A real human in a Coffin is converted into an information body — pseudo-spirit-particlized — and transferred to the Singularity. It is a well-crafted magical theory, made possible precisely because the Singularity is not normal spacetime.
— Fate/Grand Order, Avalon le Fae, Section 21
Since she explicitly says "information only," we can understand that no physical body — such as Fujimaru's actual flesh — moves at all during Rayshift.
Morgan, in Part 2 Chapter 6 (Avalon le Fae), performed a Rayshift to fly to the past of the Lostbelt Britain.
Morgan sent her own information into the past. As a result, past Morgan within the Lostbelt had current Morgan's memories, information, and emotions entirely overwritten onto her. (Current Morgan, we are told, dissipated and vanished.)
Rayshift can only move a person's "information." It cannot transport a person's physical body to the destination as-is.
However: if one's past self exists at the destination, that past self can serve as the "physical body," making it possible to Rayshift there (send out information and overwrite it).
So what about Fujimaru?
The Singularities that Fujimaru Rayshifts to — ancient Rome, ancient Mesopotamia, and so on — contain no past Fujimaru to serve as a physical body.
So then: where does the body of Fujimaru, who is active and present in the Singularity, come from?
- Rayshift can only transmit information. (Fact)
- When Rayshifting a person, that person must already be present at the destination for Rayshift to be possible. (Speculative)
- If one's past self exists in the past world, that past self can serve as a vessel for the information, enabling Rayshift. (Fact)
- Past Fujimaru shouldn't exist in ancient Rome, yet Fujimaru can Rayshift to ancient Rome. (Fact)
The first three points and the last one are contradictory.
Following the logic, to Rayshift Fujimaru to ancient Rome, either:
a) Rayshift is actually capable of transmitting physical bodies, not just information,
or
b) Fujimaru actually exists in ancient Rome.
One of these conditions must hold. And between them, "Fujimaru exists in ancient Rome" seems far more interesting.
■ Professor Schrödinger, Once Again
Common sense tells us that a present-day Fujimaru cannot exist in ancient Rome — but the FGO worldview features "magic" and "true magic" that overturn common sense wholesale.
Among such suspicious sorceries, what we need is one that can forcibly make Fujimaru's body exist in ancient Rome.
The device used to make that existence happen, I propose, is the "Coffin."
Coffin means casket — a box. A person enters it, it activates, and the contents become completely unobservable from outside.
A box whose contents are completely unobservable from outside — there is only one thing that brings to mind: the box containing Schrödinger's Cat.
You place a cat in a box that is completely unobservable from outside. The box has a switch that has a 50% chance of filling it with lethal gas. You press the switch. The lid stays closed.
In this unobservable box, there is a 50% chance of a living cat and a 50% chance of a dead cat.
Common sense says: "One or the other is in there — we just can't tell from outside."
But quantum mechanics says: "No."
"The cat's state is still probabilistic; it has not yet been determined." "In this box, both a living cat and a dead cat exist in superposition."
Remarkable, isn't it?
But there's only one cat. Two cats don't come out. When you open the box, there's either one living cat or one dead cat. So when is that determined?
"It is determined the moment someone opens the box and observes the cat's state." "The act of observation is what determines it."
This is a rather distorted reading far from actual science, but taking it to an extreme: the cat wasn't killed by the gas. The culprit of the cat's death is "the observer," and the cause of death is "observation."
The cat was alive. Not because the gas didn't release — but because "a living cat was observed."
Now: the Coffin is a box unobservable from outside, and Fujimaru is the living cat (cute). Fujimaru is placed in the Coffin.
There's no gas device, so we need not ask whether Fujimaru is alive or dead. But consider reframing it this way:
"Because the Coffin is unobservable from outside, we cannot know whether Fujimaru is really in there or not."
After all, in magic tricks and mystery novels, putting a person in a box and opening it to find no one there is entirely commonplace. If it can happen in the world of stage magic, can it really not happen with magecraft (magic) or true magic?
This means: inside the Coffin, there is a 50% chance that Fujimaru is not there, and a 50% chance that Fujimaru is there — two possibilities overlapping inside the box. Neither has been determined yet... or rather, since "both are present," the question of which one holds is invalid.
We just put Fujimaru in the Coffin, yet through the sleight-of-hand of logic and magecraft, we have generated a 50% possibility that "Fujimaru is not in here." Remarkable.
If Fujimaru is not in the Coffin, then where is Fujimaru?
A magic trick where a person disappears from a box — where did the person go? The most unambiguous answer is "somewhere in all the world except the box."
So where has the Fujimaru who is not in the Coffin gone? "Somewhere in all the world except the Coffin." If there is a 50% chance that Fujimaru is not in the Coffin, then there is a 50% chance that Fujimaru is somewhere in all the world except the Coffin.
And here's the thing: we want to find Fujimaru not just "somewhere in the world," but specifically at a particular Singularity.
■ Observation Creates Reality
Say we want to Rayshift Fujimaru to ancient Rome. First, put Fujimaru in the Coffin and create the state: "Fujimaru might not be in here."
Next, generate the reality: "Fujimaru might be somewhere in the world except the Coffin — specifically, in ancient Rome."
We established: "The reason the cat is alive is that a living cat was observed."
Extending this:
"If Fujimaru is in ancient Rome, the reason is that Fujimaru was observed in ancient Rome."
Chaldea has Chaldeas and Sheba — remarkably precise instruments that can scan any specific location on Earth. Using these, combined with some further suspicious magecraft:
Let us absolutely find Fujimaru in ancient Rome.
Then the reality that Fujimaru's body exists in ancient Rome comes into being.
Fujimaru has disappeared from the Coffin, so Fujimaru must definitely be somewhere in the world. If Fujimaru is definitely somewhere in the world, then there is some possibility that Fujimaru is in ancient Rome among those locations. That small possibility is raised to 100% through magecraft or true magic.
In the framework of this article, "observation determines reality," so anything that could be observed absolutely exists there. Common sense says: "Fujimaru is there (cause), therefore Fujimaru can be observed there (effect)." But if you hammer quantum-mechanical ideas into service with sheer brute force: "If you magically observe what you wish there (cause), what you wished for begins to exist there (effect)" — the relationship inverts.
As I've noted in other articles, this is remarkably similar to Gáe Bolg — "the result of hitting is caused first, and then the spear is thrown."
Fujimaru's body has now come to exist in ancient Rome. From there, nothing is difficult. Wherever a body exists to serve as a vessel for information, Rayshift is possible. Fujimaru's information is transmitted toward Fujimaru's body in ancient Rome. The body then becomes inhabited by Fujimaru's current memories, knowledge, and emotions — and Fujimaru can operate in ancient Rome as a physical presence.
One question arises: "Since the Fujimaru who disappeared from the Coffin shows up in ancient Rome, isn't transmitting the information unnecessary? The missing person appears there, right?" — Probably the transmission is still necessary.
For instance: "The Fujimaru observed in ancient Rome right now is not necessarily the Fujimaru who just entered the Coffin."
Fujimaru has entered the Coffin dozens of times. The Fujimaru found in ancient Rome might be the Fujimaru who entered the Coffin on a past Rayshift — or the Fujimaru who will enter the Coffin on a future one. But the Fujimaru we want in ancient Rome is the one who entered just now, so we transmit the current Fujimaru's information and overwrite. Regardless of which temporal Fujimaru is physically present in ancient Rome, after overwriting, the one there is the current Fujimaru.
■ Proof of Existence
Official supplementary materials contain the following:
The concept is that Masters are sent to various eras via Rayshift, but in practice they are converted into spirit-particle data and "projected/observed."
— MOONLIGHT/LOSTROOM material, p.11 (appendix to Fate/Grand Order MOONLIGHT/LOSTROOM)
The word "observed" appears here. This article's proposal is "Fujimaru is made to exist through observation, and then current Fujimaru's data is projected there" — which is consistent with the official explanation.
Incidentally, during Rayshifts in-story, the operator (often Mash) says things like "Establishing and maintaining Proof of Existence — focusing now." That's quite striking.
In the Rayshift framework proposed here, Fujimaru — who can only be located probabilistically — is being forcibly made to exist through the act of observation. As long as a living Fujimaru at that location is being observed, Fujimaru can continue to exist there. The moment observation ceases, Fujimaru reverts to "something only graspable probabilistically" — meaning Fujimaru can no longer maintain existence and vanishes.
After all, the probability that Fujimaru disappeared from the Coffin is only 50%, so the probability of Fujimaru being at a specific location in a Singularity is also at most 50%. The thing raising that to 100% is "the act of observation" — so if the observation is interrupted for any reason, it becomes catastrophic. Therefore, once Fujimaru is Rayshifted, one must firmly maintain the fact that "Fujimaru exists at the destination" through continuous observation.
Calling that the "Proof of Existence" seems fairly consistent.
An alternative reading: "Proof of Existence" might refer to the task of concealing from the world that Fujimaru has vanished from the present. The MOONLIGHT/LOSTROOM glossary entry on Rayshift says:
The deviation in history and causality caused by the Master's absence is calculated, a provisional formula is applied, and history is properly corrected.
— MOONLIGHT/LOSTROOM material, p.11
Calling that "Proof of Existence" wouldn't feel out of place either.
■ Singularities Are Easy to Rayshift To
However, this proposal has a major problem.
Fujimaru is a modern person, so Fujimaru absolutely cannot have been born in ancient Rome's era. Therefore, the probability of Fujimaru being observed in ancient Rome is zero percent. No matter how hard you look, Fujimaru absolutely cannot be found there.
The setting that resolves this problem is: "Rayshift is in principle only possible to Singularities." (I believe this setting exists somewhere, though I can't find the exact source right now. Fujimaru in principle only Rayshifts to Singularities, right?)
A Singularity is like a floating island cut off from the flow of history, where consistency with surrounding eras is completely ignored, and things that absolutely could not happen in that era and region happen without issue. Ancient Celtic armies in Revolutionary-era North America!
In an ancient Rome where the rules say historical consistency with the surrounding eras can be completely ignored, a present-day Fujimaru is allowed to exist — so Fujimaru can be found with Sheba's scan.
As already quoted, Morgan evaluates Rayshift thus:
(Morgan) It is a well-crafted magical theory, made possible precisely because the Singularity is not normal spacetime.
— Fate/Grand Order, Avalon le Fae, Section 21
This seems to be saying roughly: "In a vague and undefined place like a Singularity, anything can exist, so anything can be sent there." It follows that even a Fujimaru who shouldn't originally exist in that spacetime can be there without issue.
■ The Body Is There on the Way Back
When Fujimaru finishes work in a Singularity and returns to Chaldea, the return trip works in reverse.
Inside the Coffin, Fujimaru is there or not — fifty-fifty. Turn the dial (or whatever the mechanism is) and activate the "Fujimaru is in the Coffin" side.
Simultaneously, retrieve Fujimaru's information from the Singularity's Fujimaru. Re-overwrite that information onto the Coffin-Fujimaru's body. Done.
From the perspective of the Fujimaru in the Singularity, this is a Morgan-style Rayshift directed at one's own body in Chaldea. Therefore, the Singularity Fujimaru's body — the one not in the Coffin — dissipates (vanishes), just as Morgan did.
To make something exist at the Rayshift destination, it must become absent at the original location. Therefore the original-location version is forcibly made absent = dissipates. Original Morgan dissipates when she Rayshifts, and Singularity Fujimaru dissipates when Rayshifting back to Chaldea. That's my understanding.
In summary, the Coffin's role is to put Fujimaru's body into an ambiguous state of: "Has it vanished...? Or is it still in here...? Which is it~?"
While Fujimaru is on assignment in a Singularity: "The Coffin-Fujimaru might have vanished. In that case, let's go with vanished — being in the Singularity is fine!"
When Fujimaru returns from Singularity to Chaldea: "The Fujimaru we thought had vanished actually hadn't, so Fujimaru can return to the body in the Coffin. Return successful!" — a conveniently flexible judgment.
The Coffin's purposes are twofold (in this article's hypothesis):
- To enable Fujimaru's body to be found at the Rayshift destination (by pseudo-annihilating the present Fujimaru).
- To preserve Fujimaru's body so Fujimaru can return from the Singularity.
Therefore, if one already knows their own body definitely exists at the destination, a Coffin isn't needed. If not returning to real-time real-space is acceptable, a Coffin also isn't needed.
Hence Morgan — who knew she herself would be at the destination and would return to the present after living 6,000 years — had no need for a Coffin.
● One Million Superimposed Fujimarous
There's the established idea that Fujimaru has a 100% Rayshift success rate — quite the extraordinary feat.
In the earlier article linked at the start of this piece, I discussed why Fujimaru is so exceptional. It may be because Fujimaru is a superimposed state in which a huge number of us FGO players are packed into a single body.
These figures are from one to two years ago, but FGO reportedly has an estimated roughly one million monthly active users. The number may have dropped somewhat by now, but we can reasonably say there are about one million Fujimarous in the world.
Fujimaru is one person — and yet this one Fujimaru is a multiple-superimposed existence of one million Fujimarous overlaid.
You put a cat in a box and press the button, and the cat becomes a multiple superimposed existence of living-cat and dead-cat. Likewise, Fujimaru is a multiple superimposed existence of players number 0000001 through 1000000 — one million variants overlaid.
Put Fujimaru in the Coffin and close the lid: the probability that Fujimaru is in the Coffin is 50%. (Writing it out, that's quite a statement.)
But if Fujimaru consists of one million superimposed variants, that 50% is not just any 50% — it can be expressed as:
50% ÷ 1,000,000 × 1,000,000
That is: there's a 0.00005% chance that "Fujimaru #0000001" is in there. A 0.00005% chance that "Fujimaru #0000002" is in there. A 0.00005% chance for Fujimaru #0000003... and so on a million times.
And since the probability that Fujimaru is "not in" the Coffin is also 50% — in other words, the probability that Fujimaru is in some Singularity (other than the Coffin) — is also 50%:
There's a 0.00005% chance that "Fujimaru #0000001" is in some Singularity. (abridged) ...There's a 0.00005% chance that "Fujimaru #1000000" is in some Singularity.
In other words: lock Fujimaru in the Coffin and render existence/non-existence unverifiable — and Fujimaru becomes a person who thinly permeates all spacetime, potentially present everywhere simultaneously.
A person who can potentially be present throughout all spacetime would be remarkably easy to observe at a specific Singularity. With an ordinary human, you'd be working with: "Somewhere across the vast span of human history, in one of the countless Singularities large and small, this one person exists with 50% probability" — observation would be virtually impossible. In that case the Rayshift success rate would likely be nearly zero.
That, I propose, may be the true nature of Fujimaru's 100% Rayshift success rate.
■ Ansummon, Summon, and Heroic Spirit Summoning
In the Rayshift execution sequence, a system announcement says something like: "Ansummon Program — Start. Beginning spirit particle conversion."
Ansummon.
"Summon" means to call forth. The prefix "an-" (un-) negates it, so literally something like "non-summon" — probably intended as "reverse-summon" or "un-summon."
Searching "unsummon" brings up Magic: The Gathering's card "Unsummon" — the return of a summoned creature to its origin. It appears to be modern fantasy terminology rather than traditional English, described in Wiktionary as: "To send (a summoned creature) back to its original location."
FGO describes sending Fujimaru to a Singularity via Rayshift as "un-summoning" or "returning."
Come to think of it: bringing a Heroic Spirit from the Throne to Chaldea is "Summon," so sending Fujimaru somewhere would be "Ansummon (un-summon)."
If sending Fujimaru from Chaldea to a Singularity is "un-summoning," then calling Fujimaru back from the Singularity to Chaldea would be "forward-summoning" — that is, "Summoning."
Converting the Fujimaru standing in the Singularity into information only, transmitting that information to Chaldea, and overwriting it onto the body in the Coffin (Rayshift) is "Summoning."
And then I realized:
Transmitting a Heroic Spirit's information from the Throne of Heroes to Chaldea, and overwriting it onto a mannequin (a body / spirit origin) made of magical energy to render it operational — that is Chaldea-style Heroic Spirit Summoning.
They're doing the same thing. Rayshift and Chaldea-style Heroic Spirit Summoning are the same thing.
It's natural for Chaldea to possess both Rayshift and Heroic Spirit Summoning — because they are the same thing.
Both involve: "Preparing some physical body in advance and then possessing it with memories, skills, and emotions (information)." They are nearly identical.
This brings to mind the story of Morgan. Morgan, summoned to the Lostbelt Britain by Beryl Gut, fully analyzed Rayshift that very day and Rayshifted to her past self that same night. On the day she was summoned, Morgan had only exchanged pleasantries with Beryl. She had never seen or experienced Rayshift. So how could she analyze something she'd never seen?
But Morgan had just been summoned via Chaldea-style Heroic Spirit Summoning, and experienced it firsthand. If Rayshift and Chaldea-style Heroic Spirit Summoning are nearly identical, analyzing her summoning would give her the grasp of Rayshift needed.
Another tangential point: according to Katatsuki Kōhon, Zelretch's method of parallel world travel uses nearly the same idea as Rayshift:
For instance, to move from World A to World B, the jewels in World B gather in a rush until they form Zelretch's shape, and then Zelretch's soul transfers there. Instantly, the jewel golem transforms into Zelretch. At this point, the Zelretch who was in World A returns to the original pile of jewels.
— Katatsuki Kōhon, p.34
Rayshift involves handling souls, which makes it seem like Third-Magic-adjacent technology — but in fact it seems to draw heavily on Second Magic derivatives. It wouldn't be strange if there were backstory along the lines of "Zelretch provided the Animusphere family with the technology at some point in history."
And one more tangential thought to pursue. Chaldeas is said to be a copy of Earth's soul placed into a model of Earth. Adjusted slightly, that sounds like Rayshift:
"Prepare the physical model of Earth in advance, and then possess it with soul information."
The core engineering behind the creation of Chaldeas might itself be Rayshift... though it's a little odd that the original Earth didn't dissipate and vanish. One could perhaps reason: "The reason the original dissipates is that the world applies a corrective force against two identical things existing simultaneously — but since Earth is the world itself, the corrective force does not apply."
If the core engineering of Chaldeas is also Rayshift, then Chaldea's three great super-technologies: "Heroic Spirit Summoning" "Rayshift" "Chaldeas" ...are all built from a single foundational theory. If the Animusphere family possessed that foundational theory, they could have built all three super-technologies.
I love it. This kind of "truth that converges to a single point" is exactly my preference. (This blog is basically a place where I write "this is what I like.")
■ The Superimposed State of Uncertain Life and Death
Looking through supplementary materials on Rayshift, one finds the Coffin described as things like: "A magically created box that is both living and dead" "A device that renders the Master's vital signs indeterminate"
Most recently, Manga de Wakaru! Fate/Grand Order ("Understanding FGO Through Manga") offered a similar explanation:
(Gareth) So the mechanism of Rayshift is: create a superimposed state of uncertain life and death in a sealed space where information is blocked, and then project your information into another spacetime.
— Riyo, Manga de Wakaru! Fate/Grand Order, Chapter 405
What this article has been calling the "existence/non-existence" state and the "living but dead / superimposed state of uncertain life and death" appear to be one and the same. Personally, "existence/non-existence" is the intuitive framing for me — but I believe there is a strong reason it is expressed as "life or death." Let me explain.
First: the phrasing "superimposed state of uncertain life and death" extremely powerfully evokes Schrödinger's Cat. This serves as a significant hint pointing toward the truth that "Schrödinger's Cat is the core idea of Rayshift" — assuming that is the truth.
Second: Heroic Spirit Summoning involves "giving dead people — reduced to pure information — a magical body and possessing it with them." The reminder that Heroic Spirits are the dead appears all over the place. And in this article's framework, Heroic Spirit Summoning and Rayshift are the same thing. By sprinkling "life and death" language throughout both the explanation of Heroic Spirit Summoning and the explanation of Rayshift, the hypothesis "Heroic Spirit Summoning and Rayshift are the same thing" becomes easier to arrive at and construct.
Heroic Spirit Summoning can be rephrased as a technology for retrieving the information of the dead; Rayshift as a technology that pseudo-kills the subject to transmit their information. Perhaps this is fundamentally "a technology for handling the information of the dead."
Third: Team A, when preserved in Coffins, were called by a mysterious light and told "choose: to live, or to die." A person in a Coffin in the "living but dead superimposed state" being told "choose: to live or to die" is elegantly coherent. When Nasu Kinoko designed the Rayshift setting, he presumably already had a plan for "Team A being forced to choose life or death." The setting and the story line up nicely. (Thinking of it this way, Consort Yu's Rayshift affinity — given her fluid relationship with life and death — makes perfect sense.)
Fourth: If "life/death" and "existence/non-existence" are the same thing:
"A dead person is judged as non-existent at their original location, and therefore may exist somewhere else (Rayshift is possible)."
The most extreme implication of this idea is: "A dead person can be made to be alive somewhere else."
If this could be used to resurrect Kadoc, that would be wonderful — but it probably won't work out that neatly. More likely, the person this brings back is Marisbury, who shot himself after being cornered by Daybit.
Marisbury, who died by suicide at that moment, is judged as "non-existent" and thus meets the conditions for Rayshift. He could appear alive somewhere else at the moment of his death. Even if his body is lying there, the non-existence judgment is already satisfied.
■ The Purpose of Rayshift
(Morgan) In the isolated world of a Lostbelt, a thaumaturgical formula capable of this level of power is abnormal. ...If you ever have the opportunity, return to the original causality. What Chaldea is. What Rayshift was prepared for.
— Fate/Grand Order, Avalon le Fae, Section 24
Morgan departed after issuing this homework: "Think about what purpose Rayshift was created for."
The homework-setter Morgan is a person who Rayshifted to the past and altered history. It's doubtful she's done anything more drastic than that. She likely believes "the ultimate act realizable through Rayshift is historical alteration."
So the straightforward model answer to the homework is: "Rayshift was created to alter the past." Marisbury was the one who put Rayshift into practical use, so Marisbury developed Rayshift in order to alter the past.
History has almost certainly already been altered, and the characters simply don't know it.
As I wrote in detail elsewhere, Marisbury learned after the fact that something called the Holy Grail War had taken place in 2004. Someone had won and had their wish granted. According to Olga Marie, Chaldea learned of this in 2010:
(Olga Marie) Laplace's observation confirmed a special Holy Grail War in this city in 2004. (abridged) Chaldea learned of this fact in 2010. Father... I mean, the former director used this data to create the summoning ritual.
— Fate/Grand Order, Prologue, Section 4
The 2010 Marisbury thinks: if only he had participated in that 2004 Holy Grail War, he could have secured the funding to operate Chaldeas...
So: he researches the weaknesses of the Servants appearing in that war, and Rayshifts to his own past self before 2004 (he can execute this at the moment of his own natural death). His younger self — carrying all the experience up to the moment of death — materializes in the past.
He obtains Solomon's rings and dominates the 2004 Holy Grail War. Uses the funds to complete Chaldeas (historical alteration achieved). Executes the Earth-whitening using Chaldeas.
In this scenario, the history Marisbury altered is the 2004 Holy Grail War outcome. This causes the event "Chaldeas is completed" — which should never have occurred — to materialize, leading to the Earth-whitening. In other words, the history from 2004 onward in FGO is a branch diverging from the original history.
(Much of this section I'm writing based on what I learned from the following video — please check it out: [FGO Theory] Current Logical Analysis of Singularity F )
■ True History or Singularity?
Following this thread: the history in which "Marisbury didn't participate in the Holy Grail War and Chaldeas was never completed" is the true canonical history — meaning what Da Vinci and Fujimaru believe to be canonical history is, at least from 2004 onward, arguably not canonical.
Meanwhile, Morgan caused the "withering of the Fantasy Tree" — an event impossible in canonical history — founded a Fairy Kingdom impossible in canonical history, and accumulated 2000 years of Fairy Calendar impossible in canonical history. Since the withering of the Fantasy Tree onward, Britain was no longer a Lostbelt, so that era is called a "Singularity."
So what should we call the post-2004 world produced by Marisbury's historical alteration — a world that cannot be called canonical?
Might it be called a "Singularity"?
Marisbury's attempt to alter history likely turned the Fuyuki of 2004 into a Singularity. If that went uncorrected and continued — it would spread across the entire world. A Singularity overwriting the true history.
The characters in FGO think Singularity F is a Singularity because they believe the world they belong to is canonical history. But what if the baseline of FGO is itself entirely a Singularity? Something that looks like a Singularity from within a Singularity.
If canonical history were to collide with the Fuyuki of FGO, it would look like a Singularity from within...
Singularity F is, then, a pocket of true canonical spacetime floating up at a single point within a world where all of existence has become a Singularity...
I adore this kind of idea — it feels like the world has been turned inside out.
That's why standing guard in Singularity F is Saber — the true victor of the canonical Holy Grail War. Saber is attempting to re-overwrite all the world in that spacetime of "what appears to be a Singularity but is actually canonical history" — to win "the battle to reclaim true history." It's Saber who's performing Singularity correction...
If that's the direction this is heading, it creates enormous problems. I'd want to support Saber — but letting Saber win would erase the whitening problem, while simultaneously erasing everything Fujimaru has traveled through. Can we accept that? I absolutely cannot.
But "your world needs to disappear, so your world will disappear" is the Lostbelt story inverted and aimed at the protagonist — and that's a compelling direction... That's where my thoughts on Rayshift end for now.
■ Addendum 1: Why Mash Could Be Sent to the Past
After writing this article, I encountered the question: "Why could Morgan Rayshift Mash to the past?"
Morgan used a magic called the "Water Mirror" to hurl a calamity into the Fairy Calendar era — and accidentally hurled Mash instead. But Mash's body doesn't exist in the Fairy Calendar era.
If Rayshift truly only transmits information, and if someone without a body at the destination would simply vanish, then Mash appearing with a physical body in Fairy Year 400 would be contradictory. Mash isn't there in that era.
...Or so I thought, but on re-reading Avalon le Fae, I resolved it myself. Morgan possesses physical transfer magic — the ability to move objects as objects.
(Beryl) Morgan's "Infinity Mirror" is something else — practically magic!
You won't find this kind of effortless "Transfer" anywhere in the pan-human history.
Only a "Witch" left behind by the ages could manage it. That alone merits reverence. (abridged) A transfer (Shift) that is essentially dimensional connection itself, performed by linking a parent mirror with multiple child mirrors. (abridged) On top of that — a Rayshift without a Coffin, which even Chaldea hasn't achieved!
Who'd have thought she was flinging "calamities" to ancient times and pawning off debts onto the "past"!
— Fate/Grand Order, Avalon le Fae, Section 14
Beryl, upon witnessing Baobhan Sith's teleportation, delivers this long expository monologue.
Morgan possesses warp magic called "Infinity Mirror" that connects two spatial points and allows instant relocation. Its mechanism is described as "dimensional connection."
What dimensional connection means is uncertain — but in TYPE-MOON works, the "infinity mirror / opposing mirrors" concept is fairly commonly associated with parallel worlds (I recall it being used in the Jeweled Sword scene in stay night), so I imagine it's something akin to the Second Magic — perhaps temporarily moving to another world, then returning to a different location in the original world.
Beryl also states here that the Water Mirror's true nature is Rayshift. This long monologue by Beryl was presumably placed to resolve the contradiction between "Rayshift can only transmit information" and the story event "Mash is sent to the past world."
Since Morgan possesses both "magic that physically moves objects to another location" and "magic that transmits an object's information to the past," combining them would allow "physically sending an object to the past intact."
That the Water Mirror uses the Infinity Mirror's technology is evident in the following scene:
(Tonelico) Hmm... I sensed a great magic of the same type as the "Infinity Mirror" and came to the eastern shore...
Oh. Are you perhaps a northern fairy?
One who failed at a transfer and got thrown out here in the middle of nowhere?
— Fate/Grand Order, Avalon le Fae, Interlude/5
Tonelico sensed a magic resembling the Infinity Mirror and came to that location — where she found Mash, who had been sent through the Water Mirror. She wonders if it's a northern fairy who bungled a transfer.
Since Tonelico looks at the traces of the Water Mirror and thinks "that's the Infinity Mirror," it's virtually certain that the Water Mirror is a combination technique of Rayshift and Infinity Mirror.
■ Addendum 2: Friends as Rayshift Destinations
I discussed how Fujimaru is an existence formed by the superposition of one million players — and on that note:
Each of us players is a different individual, yet simultaneously we are all the single person Fujimaru. In a sense, we are all the same person — through Fujimaru.
Now: there is a game mechanic allowing you to borrow one Servant from another player (Friend).
What if the ability to borrow another player's Servant is itself Rayshift?
Since we are all Fujimaru, we all possess Fujimaru's body. That means we can extract information from ourselves and inhabit another Fujimaru with it — and extract information from someone else and inhabit our own body with it.
We players are all Fujimaru, but our story progression varies. We may not have summoned a Servant that someone else has summoned, and vice versa. But since we're all Fujimaru, information transmission back and forth is freely possible.
When you borrow a Servant from someone, you are Rayshifting a part of that person's Fujimaru-information into your own self. When you lend a Servant, you are Rayshifting your own information toward someone else.
When another Fujimaru's information has been Rayshifted into you, you are simultaneously yourself and "another Fujimaru." Therefore you can summon "another Fujimaru's" Servant as if it were your own.
I found this imagination interesting enough to record here. Let's set aside the inconvenient issue that "the original Fujimaru doesn't vanish" in the name of keeping things fun.
■ Addendum 3: If Loa's Reincarnation Is Rayshift, What Is Olga Marie's Role?
Tsukihime features a character named Loa — a vampire with the special ability to reincarnate upon death and persist in this world indefinitely.
While still alive, he designates his next reincarnation host. When he dies, he possesses the designated fetus or infant entirely — body and soul. That fetus or infant has Loa's memories and abilities overwritten onto them, and when they grow up, they become Loa himself.
- Conditional on the death of the original self (becoming non-existent).
- Transmitting all one's information toward another body.
What Loa calls "reincarnation" is extremely Rayshift-like — it might basically be Rayshift.
The problem with this interpretation is that "Loa's Rayshift destination is not Loa's own body."
In Morgan's Rayshift, past Morgan existed at the destination, enabling information to be transmitted there. In Fujimaru's Rayshift, per this article's proposal, magic forcibly raises the probability of Fujimaru's body being at the destination to 100%. Both cases assume "the person's own body is at the destination" as a prerequisite.
Yet Loa's reincarnation target is a completely different person — so being able to Rayshift there would be strange. Hence one could conclude that Loa's reincarnation is not Rayshift.
But.
If there existed a magical method of the sort: "I define this fetus and myself as the same person" — the story would be different.
After all, in the TYPE-MOON worldview, "manipulating conceptual layers" as a supernatural method is prominently featured. If you inscribe "you are already dead" onto the conceptual layer of an immortal monster, the monster that can never die will die.
If you inscribe "You are me" — you and the target become the same person, and you can Rayshift to the target.
On a slightly different note:
There is the established setting that "Director Olga Marie has a 0% Rayshift aptitude." I've been idly wondering what that setting exists for — and a small idea came to me. In a word:
"Marisbury planned to Rayshift into Olga Marie's body."
Marisbury knew he would die. He decided that when he died, he would upload all his information to some "server-like entity" — Trismegistus, Chaldeas, whatever. Rayshift technology enables converting an entire human into information, so presumably this would be possible.
Then, after advancing various schemes within the server, when he needed to return to the real world with a physical body, he would Rayshift toward Olga Marie's body. Olga Marie would be overwritten by Marisbury's soul and effectively become Marisbury.
On the question of whether Rayshifting toward Olga Marie's body is possible: refer to Loa's reincarnation. If some method could be used to "define Marisbury and Olga Marie as the same person" — it would work.
Olga Marie should have received Marisbury's magic crest transplanted onto her. Olga Marie carries Marisbury's magic crest.
"Since she carries Marisbury's magic crest, Olga Marie is Marisbury" — defining this in magecraft terms doesn't feel particularly strange.
So let us posit: "Marisbury intends to Rayshift into Olga Marie's body."
Under this assumption, Marisbury may not want Olga Marie Rayshifting here and there on her own. Per this article's model, Rayshift "works by making a person's very reality ambiguous."
In our model, Chaldea-style Rayshift means: "Converting a person called Fujimaru into a possibly-non-existent fictional entity, and treating the imaginary Fujimaru said to be at the Singularity as real."
If Olga Marie were to Rayshift somewhere, she would be peeled off from reality and rendered an indeterminate, neither-here-nor-there thing.
For the Marisbury in this model, Olga Marie is an anchor for his return to reality — she must be firmly bound to the real world. Absolutely cannot have her going wobbly.
Therefore Marisbury pre-emptively "strips" Rayshift aptitude from Olga Marie.
The ideal would be to strip aptitude through magical manipulation — but merely inputting into Chaldea's system: "Output a result of zero Rayshift aptitude for Olga Marie" and "Halt Rayshift if Olga Marie enters a Coffin" would suffice.
Assuming Marisbury's scheme as described above, it makes sense that the First Emperor describes Rayshift as "smelling of wickedness." Because this is fundamentally a technique premised on seizing another person's existence entirely.
(First Emperor) I had collected every forbidden art and banned technique from every corner of all China...
Now that I think about it, no wonder even Xu Fu fled.
— Fate/Grand Order, Interlude: The Melancholy of the Ruler
The First Emperor, who had gathered "forbidden arts" and "banned techniques" from all over the world in pursuit of immortality, says:
(First Emperor) First of all, this mechanism called Rayshift just doesn't sit right with me... There's a faint whiff of wicked sorcery about it.
— Fate/Grand Order, Interlude: The Melancholy of the Ruler
If Rayshift is something aimed at seizing another's body to achieve immortality — as Loa does — then the First Emperor, who has strong opinions on forbidden arts for immortality, would naturally call it wicked.
Come to think of it — I watched Lord El-Melloi II's Case Files as an anime — there was a line along the lines of: "Marisbury lost interest in Olga Marie the moment he realized the Fuyuki Holy Grail was useless" (paraphrased from memory — was there?).
If the Fuyuki Holy Grail can't properly grant wishes, funding wouldn't materialize, Chaldeas wouldn't activate, and if Chaldeas can't operate, the conspiracy beginning with Earth-whitening becomes impossible — rendering meaningless both uploading himself to a server and downloading into Olga Marie's body.
Marisbury's sole use for Olga Marie was as a Rayshift destination for his return to reality. Once the conspiracy fell apart, that use evaporated and his interest in Olga Marie vanished — which rather adds up.
(Alternatively: he decided to go to a parallel world, i.e. he resolved to leave this world — so he lost interest in this world's Olga Marie. That also works.)
Speaking of which: Daybit said something like "it's all thanks to Lev throwing Olga Marie into Chaldeas that we had a comeback."
(Daybit) At that point, Goetia's scheme — the Demon Pillar's plan — was perfect...
But within that, what could truly be called a miracle was the emotion Lev Lainur directed at you.
Without that, there was no road to our reversal. The Mage King Solomon. No — the Demon King Goetia.
In that moment, as he incinerated human history, he simultaneously gave birth to human history's guardian.
— Fate/Grand Order, Epic of Remnant: Nahui Mictlan, Section 19 (italics as in original)
Thanks to Lev, Olga Marie's physical body was erased from the present world. And thanks to that, Marisbury was rendered unable to return to reality in physical form. Ha! Serves him right. — That reading, at least, seems plausible.
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