Death Star-vader, Demon Maxwell

(Usable when both fighters' vanguards are grade 3 or greater, and the number of face up G guardians in your G zone is three or less)-Opponent Turn's Guard Step-[Choose a card with "[Heal] Heal" from your hand, and discard it] Call this card to your from face down. :[Choose a unit in your back row, and lock it] When this unit is placed on , you may pay the cost. If you do, this unit gets +5000 until end of that battle.