Holy Grail War

A term for a competition to acquire the Holy Grail.
So long as the prize has the same abilities as the Holy Grail of legend, even a battle for a fake will be deemed a Holy Grail War.
However, the Fuyuki Holy Grail War is particularly special, as the Servant System that turns Heroic Spirits into familiars is something unique to Fuyuki itself.
The preparations and arrangements were all handled by the Association, and they are more or less in charge of running the ritual. But, since it’s a battle for the “Holy Grail” the Church refused to just sit idly by.
“It matters not if it is real or fake. It is our duty to manage the Holy Grail.”
With that, they dispatched a supervisor to Fuyuki, scheming to snatch away the Holy Grail from the magi should an opening present itself.
…Basically, the game software was developed by magi affiliated with the Association, but the rights to the hardware that runs the game belong to the Holy Church. Really, it’s a pretty unreasonable setup.

Fate/side material: Fate Encyclopedia

“Many magi of the world. Listen.
When thou illuminates the world with thy desire,
Thou shalt become the criminal which bears the name of the Savior.
No matter what era, no matter how long time continues to flow, achieving the summit through battle is the providence of man.

To all magi who were beckoned by the Moon to its cyber world.
Thou must exceed thyself and prove thee be the strongest.
The throne of SE.RA.PH is,
Bound to only answer the strongest of wishes———”

The Holy Grail War created by Moon Cell.
This is the fight for survival between 128 Masters that takes place on the seven seas virtual stage that was created inside the Moon.
Moon Cell regularly summons and gathers humans from Earth, and makes them compete for the right to use the power of Moon Cell for just once.
The competition is carried out in tournament style, and the 128 Masters fight single elimination battles until there is only one standing in the end.
This competition is a death game where half the participants are eliminated each round. Once you have entered the Holy Grail War, the only way to return home alive is to become the ultimate victor of the tournament.
Moon Cell does not desire “the strongest individual.” This battle for survival is just an object of observation, and functions as a method to adjust and calibrate the metrics used to measure humans.
Of course, regardless of what the victor wishes for, and what kind of conclusion their wish may bring about, everything is recorded in order to better understand humans.

Fate/EXTRA Material: Encyclopedia of Fate/EXTRA