Death and Darkness

+1: Create a 2/1 Legendary creature named Darkness with "during your upkeep, sacrifice a creature. Then put a +1/+1 counter on this creature."
-2: Put a -1/-1 counter on each creature on the battlefield, then proliferate. The gain 1 life for each creature that died this turn.
-7: Exile up one to target creature, return up to one card from your graveyard to your hand.