Star-vader, Chaos Breaker Dragon

(This ability is active if you have four or more damage): 1-card with "Star-vader" in its card name] During your opponent's end phase, when an opponent's locked card is unlocked, you may pay the cost. If you do, retire that unit, and draw a card. :[ 1 & Choose a card with "Star-vader" in its card name from your hand, and discard it] Choose one of your opponent's rear-guards, and lock it. This ability cannot be used for the rest of that turn. (The locked card is turned face down, and cannot do anything. It turns face up at end of the owner's turn.) /:Lord (If you have a unit without a same clan as this unit, this unit cannot attack)