Rakdos, Lord of the Pit

Rakdos, Lord of the Pit gets -X/-X where X is the number of cards in your hand.
Hellbent — At the beginning of your upkeep, if you have no cards in hand, exile the top three cards of your library. You may play them this turn. Whenever you cast a spell from exile this turn, Rakdos deals 2 damage to each opponent.