Stealth Dragon, Utsuroi

:Sentinel :[Choose a card from your hand, and discard it] When this unit is placed on from hand, you may pay the cost. If you do, choose one of your units that is being attacked, and it cannot be hit until end of that battle. (Drop zone):[Choose one other "Stealth Dragon, Utsuroi" from your drop zone, and put it on the bottom of your deck] When the attack of a dominated unit hits a vanguard during your turn, you may pay the cost. If you do, return this card to your hand.