Ionization Star-vader, Hafnium

:[Legion 20000]"Unrivaled Star-vader, Radon"(If your opponent's vanguard is grade 3 or greater, this unit may return four cards from your drop zone into your deck once, search your deck for the specified card, and Legion) :When this unit attacks a vanguard, if this unit is [Legion], choose units equal to the number of your opponent's locked cards from among your units, and those units get +5000 until end of turn. : 2 Choose one of your opponent's rear-guards in the back row, and lock it. (The locked card is turned face down, and cannot do anything. It turns face up at end of the owner's turn.)