Blaster Blade Seeker

:When this unit is placed on or , [discard a card from your hand], choose one of your opponent's front row rear-guards, and retire it. Choose one of your vanguards with "Seeker" in its card name and grade less than or equal to your opponent's vanguard, and that unit's original becomes 2 until end of turn. :At the end of the battle this unit attacked, if you did not ride this turn, [put this unit on the bottom of your deck], and draw a card.