Snow Elemental, Hyakko

:[Choose two of your units named "Snow Elemental, Hyakko" on , and bind them face up] Choose one of your vanguard's abilities with cost " 4" or more and " 6" or more, and until end of turn, that cost becomes [?] until the next time it is paid. (A ? cost is paid by declaring that you are paying it) :This card is from all clans and nations.