The Power That Destroyed Mythology
No matter what kind of magecraft it was, successfully activating it required three basic conditions.
First: the power required to activate the thaumaturgical formula.
Second: the procedure required to activate the thaumaturgical formula.
Third: the command required to activate the thaumaturgical formula.
The first condition referred to magical energy. Without sufficient magical energy, no matter what kind of magecraft it was, it could not be activated successfully.
The second condition referred to the formula itself—that is, the Magic Circle, ritual, magical materials, and so on.
The third condition referred to the incantation and spell.
Magus needed to possess the ability to construct, establish, and draw the formula, then chant an incantation capable of interfering with phenomena and inject the required magical energy into the formula. Only then could magecraft manifest.
Although some magecraft required additional conditions for activation, and the external environment could also affect the state of its activation, generally speaking, as long as the three conditions above were met, magecraft could be activated smoothly.
The same applied to Heroic Spirit Summoning.
Setting aside the decisive magecraft used to save the human world, the reason ordinary Heroic Spirit Summoning could not be activated successfully was simply that the required magical energy was too immense and the summoning ritual too intricate.
In other words, the first and second conditions could not be fulfilled, so the summoning could not be completed successfully.
Therefore, the Holy Grail War ritual needed the Holy Grail to provide assistance.
Only the Holy Grail could satisfy the magical energy requirements for summoning, and only the Holy Grail could complete that overly complicated, large-scale ritual. It allowed the first two conditions to be fulfilled directly. In the end, one only needed to chant the incantation correctly and trigger the Holy Grail's summoning