Karstara the Warder

Double Breaker (This creature breaks 2 shields.)

Impede - Whenever this creature attacks, you may clash with your opponent. If you won the clash, put the top card of your deck into your shield zone face down as a new shield. (To clash, each player reveals the top card of his or her deck, then puts it on the bottom. You win if your card had the same or higher level.)