Fate Meta Information Page

Type-Moon is the name of the company (and a background entity in the setting), the 'Nasuverse' is the fan-name for the setting itself, and Fate is a specific part of the setting involving the Holy Grail Wars and the summoning of 'Heroic Spirits' as Servants. It is by far the most popular of the company's franchises and therefore gets the most attention. I like the Tsukihime/Melty Blood portion, but that's neither here nor there.

The Holy Grail War is itself is...complicated. The "public" (though since this involves magi, I mean public to the community of magi, not the world at large) reason for it is that its a ritual in which seven Heroic Spirits, or rather copies of them placed into a Servant container, are summoned to fight on behalf of seven magi for the right to obtain the Holy Grail, which is said to be able to grant any wish. The Servant fights for the Master, and the Master acts as both a power-supply and a metaphysical 'anchor' so to speak, to keep them from being rejected by the World. The Master is also provided with three 'Command Seals' which allow the Master to issue a supposedly irresistible (hint: It's totally possible to resist, or even ignore it, but there's only a handful who can pull it off) command, which also provides them a power-boost in carrying out that command.

Nominally, both the Master and the Servant would be able to get a wish, but since the ritual is fueled by the Heroic Spirits slain in combat, and the true function (to travel to the center and origin of reality, and either turn back having obtained a True Magic, or stay, fuse with the Root and gain a pseudo-Buddhist sort of enlightenment) requires all seven Servants to fuel it...well, the Command Seal are also the means by which the Master is supposed to get their Servant to kill themselves.

Shorthand for how the universe works

There exists a physical universe in Nasu -- a space wherein things such as planets and stars exist.

Humans in Nasu are unable to directly perceive or interact with it.

The "universe" that a given human interacts with is part of a local space-time domain no larger than the solar system, whose chief purpose is to render the collective beliefs of humanity as "phenomenally valid"; "the Laws of Physics" implemented within the domain are a product of human belief. Ergo, the domain itself acts as a kind of perception filter -- preventing humans from comprehending that the physics they think to be "universally valid" are really only local.

A given iteration of this domain is timeline-specific. That is, there are multiple iterations of it -- one for every timeline experienced by humanity. Collectively, a set of possible timelines that humans experience exist within something called the Tree of Time, built on top of the physical universe. This "Tree" is also referred to as the Human Universe of Awareness. The collective "Laws" that govern everything that exists or occurs within the Tree / Universe is referred to as "the Human Order" / "the Common Sense of Man." The phenomenon whereby the Human Order "corrects things" to preserve the survival of humanity is called "the Counter Force of Alaya."

The passage of time as experienced by humans has nothing to do with things outside of their context. Merlin originally exited the Tree of Time into Avalon in what was to him roughly 5XX AD; but because he isn't human, and because Avalon is outside of the Tree, he was able to physically exit Avalon and reenter the Tree as of a chronological position of 2655 BC in Grand Order.

Ergo, if an alien completely unrelated to humanity entered the Solar System, they wouldn't necessary be able to observe any of the same things that humans perceive (e.g. Mars looks completely different to them, compared to what a human might see if they visited Mars); they might not be able to witness the events of any particular human timeline that exists within the Tree of Time. It's even possible that they wouldn't be able to observe direct evidence of the human habitation of Earth.

Naturally, this means that even if the aliens arrived in the atmosphere of the planet, humans wouldn't necessarily be aware of their presence, or vice versa.

One of the functions / privileges of the Counter Force of Alaya is to flag timelines that it deems pointless for deletion / culling / pruning. Generally, "pointless" would encompass timelines that no longer branch, and timelines that have strayed too far from the course of history in the "main trunk" of the Tree of Time. Reaching a Utopia / Dystopia / Heaven / Hell / Apocalypse state without any possibility of further variation is an easy way to get flagged for deletion. Deletion is imposed upon flagged timelines roughly once a century.

The action of deleting all timelines flagged within a given century is this context referred to as a "Quantum Time-Lock." Being that the Counter Force has determined a particular "build" of history to hold the highest branching potential (therby qualifying for prioritization of preservation), the course of history along the "main trunk" of the Tree ends up being largely identical across multiple timelines across consecutive prunings, regardless of minor divergences. That is, it becomes "locked."

There exists more than one "Tree of Time." Grand Order happens in a particular Tree. Tsukihime, Prisma Illya, Prototype, and Extra are amongst those things that occur in other Trees.