A wide unobservable area that suddenly appeared on the Earth.
Named by Da Vinci, lost legacies of the Felling Theoretical Phenomenon.
The abbreviation is Lostbelt.
Surrounded by a barrier (white storm) close to a dimensional fault, internal observation by X-rays, radio waves, and visible light is impossible.
Its true identity is “a history of mankind that continues under the premise of it being different from the current history” and which has been revived from the “Pruning Phenomenon,” in other words, a history of what-ifs. The Pruning Phenomenon is literally being cut from the flow of human history, they are the Ifs of the history of humankind, which were made “nonexistent” because their possibilities became extremely narrow. Relics scraped off from current history as “unnecessary things, unnecessary fluctuations,” “history’s what-ifs that have been excluded from this Universe” cast away even from the Adjacent World Theory by “having their history discontinued for being a dead end.” (Although the Incineration of Humanity by the King of Mages was by one individual, the Pruning Phenomenon is “a page burned by the consensus of the entirety of humankind, performed by human history itself”). It has overwritten the present-day Earth and has taken over human history.
Lostbelts are assumed “what ifs” that “persisted” until the year 2018 under that assumption.

A land dominated by permafrost.
A millennial empire reigned by an emperor that was granted immortality.
A plateau of lotuses that repeats genesis and destruction through countless cycles.
And Northern Europe and the gigantic oceanic city in which the gods exist.

Lostbelts are gradually expanding.
If the Lostbelts keep extending like this, true history will be overtaken by the history of Lostbelts.
Lostbelts originally went on as “a route that is only an error for humanity” and were destroyed. The extinction of the human race will be inevitable if this insane IFs are taken as true history, and there will be no restoration of the true history that has disappeared. There is no way to restore the Earth that has been blanked and restore the correct human history other than cutting the Lostbelts from the surface.
Fujimaru Ritsuka will fight the twisted human history as a Master once again under Chaldea’s new structure.

MOONLIGHT/LOSTROOM material: Encyclopedia of Moonlight/Lostroom