[Hereafter] Chapter CXLIII: Grand Ritual (Patreon)

So this is, in FGO canon, where the first hints are really laid about the existence of Grand Servants and what their purpose is, and also therefore the moment where FGO retcons the Servant Summoning Ritual into something that existed long before the Holy Grail War and for vastly different purposes.

First problem, here in Hereafter, Romani mentions Grand Servants when talking about King Solomon all the way back during the debrief after Fuyuki. So Chaldea has, in this story, long since been established as knowing about Grand Servants.

Second problem, it felt like suggesting Chaldea was a little too incompetent to say they didn't know about Grands or even that the Servant Summoning Ritual was originally constructed for the purpose of summoning them to fight a great threat. Especially since it's a library in the Clock Tower where Hans finds this information, which means that there's no reason Chaldea shouldn't know it already.

Of course, this lore probably would have been introduced way earlier in canon, if Nasu had been fully involved in FGO's storyline all the way through.

EDIT: Moving down all the way. 5/12/2024