Whistling Arrow Eradicator, Kosanjou

:Forerunner :[Retire this unit] When the attack of your unit with "Eradicator" in its card name hits a vanguard during the battle that this unit boosted ([Boost]), you may pay the cost. If you do, reveal three cards from the top of your deck, if all of those cards have "Eradicator" in their card names, put one card from among them into your hand, and shuffle your deck. If you put a grade 3 card into your hand, 1.