Energy Field (BT11-118) [Vermilion Bloodline]

Product Details

[Counter:Attack] Negate the attack, and you can't activate copies of this card for the turn; if you have 4 or more yellow "Demon Clan" cards in play, your opponent can only attack once more for the turn.
[Permanent] If you have 4 or more yellow "Demon Clan" cards in play, you can activate this card from your hand without paying its energy cost.