Army charging at him? Gates of Babylon. Countless Noble Phantasms fired machinegun-style eliminate the threat (and it automatically reloads, IIRC).
If that's not enough, and he has to get serious, he'll pull out Ea and Enuma Elish the lot of 'em. There's not much an army of humans, magic-users or not, can do against an energy wave that shreds space and time in its area of effect.
Honestly, I think if it weren't for Kiritsugu's Master-killing strategy, Kotomine would certainly have won the Fourth Heaven's Feel thanks to Gil.
If that's not enough, and he has to get serious, he'll pull out Ea and Enuma Elish the lot of 'em. There's not much an army of humans, magic-users or not, can do against an energy wave that shreds space and time in its area of effect.
Honestly, I think if it weren't for Kiritsugu's Master-killing strategy, Kotomine would certainly have won the Fourth Heaven's Feel thanks to Gil.