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. Play this with [discard a card from hand] if you do not have any cards in your crest zone other than "Energy Generator"! If your opponent's crest zone has a card other than "Energy Generator", this ability can be played without paying the cost. Choose one of your units, and it cannot be hit until end of that battle. Remove this card.