The Forgotten Keeper of Night

When this creature enters the battlefield, each
player loses 7 life and mills 4.
Whenever a creature is put into a graveyard or
exile from anywhere, you gain 1 life.
{5}, Exile a card from your graveyard: Exile target
nonland permanent with converted mana cost
less than or equal to the mana cost of the card
from your graveyard. You may play creatures
exiled this way.