What does Nassari, Dean of Expression do?
user
At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.\nWhenever you cast a spell from exile, put a +1/+1 counter on Nassari, Dean of Expression.
assistant