Invoke the Guildpact

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
When Invoke the Guildpact enters the battlefield, exile target creature an opponent controls until Invoke the Guildpact leaves the battlefield.
As long as you have the city's blessing, your opponents can't cast spells with the same converted mana cost as the exiled card.