Domain of the True Monarchs

“While you have no cards in your Extra Deck and you are the only player that controls a Tribute Summoned monster, your opponent cannot Special Summon monsters from the Extra Deck. If a Tribute Summoned monster you control attacks an opponent's monster, it gains 800 ATK during damage calculation only. Once per turn: You can reduce the Level of 1 monster with 2800 ATK and 1000 DEF in your hand by 2 until the end of this turn (even after they are Summoned/Set, and even if this card leaves the field).”