Zemeel-Zaroc, Sengir Advisor

Defender, Lifelink
You have no maximum hand size.
At the beginning of your upkeep, draw X cards, where X is half the number of Vampire creatures you control rounded up.
You may discard Vampire cards from your hand at will.
Whenever you discard a Vampire card, you may sacrifice a swamp or 3 creatures. If you do, you may cast that card without paying its mana cost.
Feed them...