<Ancient World> Choose one of your rear-guards. If you chose a card, retire that unit, and put the top card of your deck into gauge face down. :During your opponent's turn's guard step, this card can be called to as a trigger unit, and it becomes a Grade 0/15000 guardian.
:During your opponent's turn's guard step, this card can be called to 
as a trigger unit, and it becomes a Grade 0/
15000 guardian.