Urxidian, Nezabog's Unmaker

Companion - You may cast this card from outside
the game once if there are thirty or more cards
in exile.
When Urxidian, Nezabog's Unmaker enters the battlefield, if you cast it from outside the game,
exile all cards in your graveyard and the top five
cards of each opponent's library. You may play
one card exiled with Urxidian, Nezabog's
Unmaker each turn.
Annihilator 1