Text: DEFEND RESPONSE When your Rival defends, you can Drop 1 (place 1 card from your hand on the bottom of your Main Deck) [0]: Discard 1 defending PROTECTOR.
FAQs/Rulings
When can I use Finally Captured?
It triggers as a Defend Response when your Rival defends against your attack.
What does the Drop 1 cost mean?
You must place 1 card from your hand on the bottom of your Main Deck to activate the effect.
What happens after paying the cost?
You may discard 1 defending PROTECTOR card your Rival used during defense.