Purgatory Magic, Blood Alliance
■ You may only cast this card if there is a card with "Purgatory Knights" in its card name on your field. ■ Draw a card. Then, for this turn, all cards on your field with "Purgatory Knights" in its card name cannot be destroyed nor returned to hand by your opponent's card effects. You may only cast "Purgatory Magic, Blood Alliance" once per turn.