TheFoxsCloak

Originally Posted by You

Originally Posted by tsugumi

I was on the Elements page of the wiki yesterday and I saw something I've never seen mentioned somewhere relevant, like his actual wiki page, but apparently Kayneth can make poisonous gas harmless via using his wind/water affinity? Well, supposedly according to Fate/Zero Anime Visual Guide I - Commentary:#7, p.130, anyway.

During their live watch of Zero, Narita speculates that Kiritsugu could have just used poisonous gas to beat Kayneth. Nasu speculates that a magus a strong as Kayneth would be good at detoxification (解毒) (which ironically is Waver's family's attribute). Also due to his twin elemental alignments, poisonous gas attacks wouldn't really affect him.
Narita then follows up with what the other Masters could do against Kayneth. Nasu replies that Tokiomi might be able to compete. But the other Masters would make it a Servant vs Servant battle.