Grynngal Seeker

:[Choose a card from your hand, and put it on the bottom of your deck] When an attack hits a vanguard during the battle that this unit boosted ([Boost]), if you have a unit named "Blaster Blade Seeker" in the same column as this unit, you may pay the cost. If you do, draw a card, choose a card in your damage zone, and turn it face up.