Cost: 1.

Hero Interrupt (defense): When a boost card is turned face up while the villain attacks, cancel all boost icons () on that card. Then deal 1 damage to the villain for each boost icon cancelled this way.

Ms. Marvel #14.
Preemptive Strike

The rules change to Defense makes this card much stronger than it looks. It can make you a Defending character long after the basic defense window is passed, but the real power of this card lies in its power to save a Tough card. Effectively, you make a basic defense when attacked by the Villain. This lowers the Villain's attack by your defense. Preemptive Strike takes out the Villan's boost card. What does this mean? It means if the Villain's attack is equal to or lower than your defense, its attack is zero. With no boost cards, it will deal no damage. Which means any existing Tough cards you have on you are saved for another attack! I find this card is great in Protection cards that run Tough, like Doctor Strange or Colossus!

Soulfire · 33

I have a problem with the timming. When do i have to play this card? After the boost card is turned faceup or before when i have to declare defense? I struggle with the new defence rule. We played this card always after the boost card turned face up. This proved to be very effective since when only one or no boost icon shows off this card is not effective. cheers

DaLurka · 2
Well since the card says "when a boost card is turned face up", I don't believe you have much of a choice. I think you've been playing it right. Way I see it, the new rules do not change this. However, I believe that in multi-player, if you play it when another player is attacked, you become defender (RRG 1.4 clarified this). — neothechosen · 10380
Can Preemptive Strike be played if I am defending with an ally? — Carquinyoli · 249
The card does not say "while the villain attacks YOU" so it should be playable when an ally or even another player defends. However, per the rules if you play a defense card when someone else is being attacked, you become the target of the attack, so it would switch any damage from your ally to you. — Time4Tiddy · 10
The key thing to remember is that only one player can use cards (allies, defense events, or exhausting your identity) to defend each attack. If you block with your own ally, you can preemptive strike. If somebody else blocks with their ally, you can't - it's a defense event and another player already defended the attack (in this case with an ally). There's a great example here — Blackhaven · 12
You cannot use preemptive strike if you defend with an Ally, even if it's yours. Only one character can be defending an attack and events are considered an extension of your identity. — Killbray · 4
@Killbray You're correct! I thought it was "one player per attack", not "one character per attack". — Blackhaven · 12
Rules Reference 1.5 just added "Defense-labeled abilities can be played during an attack by a player whose ally is defending that attack. In that case, the player’s identity does not become the defender.", so Preemptive Strike after your ally blocks is back on the menu. — Blackhaven · 12
@Blackhaven Correct! Since 1.5 you can play defense events even if one of your allies is defending. — Killbray · 4