Archer's Surprise Attack (FS/S34-E064 U) [Fate/Stay Night [Unlimited Blade Works]]

[AUTO] Resonate [Reveal a card named "Proof of Contract, Rin" in your hand] When you use this card's"Backup", you may pay the cost. If you do, choose one of your characters in battle, and that character gets +1000 power until end of turn. [ACT] Backup 2500, Level 2 [(1) Put this card from your hand into your waiting room] (Choose one of your characters that is being frontal attacked, and that character gets +2500 power until end of turn.)