[AUTO](RC):[Counter-Blast 1] When an attack hits a vanguard during the battle that this unit boosted ([Boost]) a unit named "Flash Edge Valkyrie", if you have a vanguard, you may pay the cost. If you do, look at the top card of your deck, search for up to one from among them, call it to an open (RC), and put the rest on the bottom of your deck.