Genesis Dragon, Bearing Messiah G-TD15/001

(This card cannot be in your main deck. Can stride when both players' vanguards are grade 3 or greater, it gains the power and card name of the heart, and at the end of the turn, return it face up) [Stride]-Stride Step-[Choose one or more cards with the sum of their grades being 3 or greater from your hand, and discard them] Stride this card on your (VC) from face down. [AUTO](VC):[Counter Blast (1)] When this unit attacks a vanguard, you may pay the cost. If you do, choose a rear-guard in any players' back row, lock it, choose a locked card, and unlock it. (The locked card is turned face down, and cannot do anything. It turns face up at the end of the owner's turn)