Within the rapidly retreating Caster’s hands, the grimoire immediately activated its ability as a prana furnace and quickly regenerated the damaged cover. The prana was only cut off during the brief moment when Gáe Dearg’s blade was in contact with the grimoire; the spear had no power to damage the Noble Phantasm itself. However, once canceled, the magecraft can’t be salvaged. Even if he wanted to repeat the summoning spell, Saber and Lancer’s holy sword and twin spears wouldn’t give him the time either.

"You bastard- BASTARD bastard BASTARD bastard BASTARD BASTARD BASTARDDDDDD!!"

- Fate/Zero: Act 7, Part 2