Destruction Tyrant, Fullblade Rex

-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 one of your rear-guards, and retire it] At the end of the battle that this unit attacked a vanguard, if you have a heart card with "Rex" in its card name, you may pay the cost. If you do, choose a card from your bind zone, call it to , and that unit gets +4000 until end of turn.