Azazel, Angel of Sacrifices

Devour 3 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with three times that many +1/+1 counters on it.)
Whenever Azazel attacks, you gain life equal to the number of +1/+1 counters on it.
At the beginning of your upkeep, you may sacrifice a creature. If you do, return Azazel from your graveyard or exile to your hand.