Saber nodded, and observed the enemy Servant painstakingly. Alone and not accompanied by his Master as usual, he was standing straight on the sandbar-less river center, as if standing on the water surface. Upon a close look, the thing which was turning into his foothold, was grotesque shadows gathering beneath the water surface. Looks like the swarm of creatures she battled at the forest the other day, had gathered under Caster's feet, forming a “sandbar”.

From the abnormal emission of prana. there was doubt that Caster was performing some sort of large-scale magecraft. The outset of this strange fog which centered about the river, was probably an aftermath due to this as well. Not showing even the expression of him focusing on his incantations, he was merely standing relaxingly― The vortex of raging prana overflowed from the grimoire in his hands, distorting even the space around it.

An extraordinary prana furnace, a Noble Phantasm which compiles the monologic procedures......Falling into the hands of a lunatic, there were no weapons as dangerous as this.

- Fate/Zero: Act 10, Part 1