Blue Wave Marshal Dragon, Tetra-boil Dragon

(Released when both players' vanguards are grade 3 or greater!)-Stride Step-[Choose one or more cards with the sum of their grades being 3 or greater from your hand, and discard them] this card on your from face down. :[ 1 & Choose a face down card named "Blue Wave Marshal Dragon, Tetra-boil Dragon" from your G zone, and turn it face up] When this unit attacks a vanguard, if you have a heart card with "Blue Wave" in its card name, you may pay the cost. If you do, until end of turn, this unit gets drive -1, and "Wave-4th time only (This ability is active during the specified battles of each turn):[Choose a card from your hand, and discard it] At the end of the battle that your rear-guard attacked a vanguard, you may pay the cost. If you do, this unit.".