Sky Guardian Supreme Dragon, Bulwark Dragon (G-BT09/015EN)

[ G guardian ] (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" from your hand, and discard it] Call this card to your (GC) from face down. [CONT](GC) Thunderstrike 3 (This ability is active when your opponent's bind zone has three or more cards) : This unit gets [Shield]+10000. [AUTO]: At the end of the battle that this unit is placed on (GC), for every four cards in your opponent's bind zone, choose up to one [Rest] rear-guard in your opponent's front row, and retire it.