I'm currently playing through F/SN at the moment, and so I'm probably being biased by the emphasis the game places on humans or magii not being able to counter Servants. That said, there was a Noble Phantasm that worked in a similar manner to Asuna's antimagic weapon. In the fourth war, one of Lancer's lances had an antimagic effect, negating Saber's armor and stopping Caster's prana furnace from functioning, but only while it was in contact with them. Asuna's weapon would probably work similarly, assuming she's not in full doomsday mode.
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Stand between the Silver Crystal and the Golden Sea.
"Youngsters these days just have no appreciation for the magnificence of the legendary cucumber." --Krityan Elder, Tales of Vesperia.
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Stand between the Silver Crystal and the Golden Sea.
"Youngsters these days just have no appreciation for the magnificence of the legendary cucumber." --Krityan Elder, Tales of Vesperia.