Supreme King's Castle

You can Fusion Summon Fusion Monsters that must be Special Summoned with "Dark Fusion" by card effects other than "Dark Fusion". Once per turn, during damage calculation, if your Fiend monster battles an opponent's monster: You can send 1 "Evil HERO" monster from your Deck or Extra Deck to the GY; your battling monster gains ATK equal to the sent monster's Level x 200, until the end of this turn (even if this card leaves the field).