Elementaria Sanctitude

:Sentinel (You may only have up to four cards with ":Sentinel" in a deck.) :You may only have one "Elementaria Sanctitude" in a deck. If your opponent's vanguard has "Triple Drive", this ability can be played without paying the cost. Play this with [discard a card from hand] if your vanguard is grade 3 or less! Choose one of your units, and it cannot be hit until end of that battle. Remove this card.