Malakir Bloodwitch

Flying, protection from white
When Malakir Bloodwitch enters, each opponent loses life equal to the number of Vampires you control. You gain life equal to the life lost this way.

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Disfigure

Target creature gets -2/-2 until end of turn.

Gatekeeper of Malakir

Kicker {B} (You may pay an additional {B} as you cast this spell.)
When this creature enters, if it was kicked, target player sacrifices a creature of their choice.

Sign in Blood

Target player draws two cards and loses 2 life.

Bloodghast

Bloodghast can't block.
Bloodghast has haste as long as an opponent has 10 or less life.
Landfall — Whenever a land you control enters, you may return Bloodghast from your graveyard to the battlefield.

Vampire Nighthawk

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Mind Sludge

Target player discards a card for each Swamp you control.

Deathmark

Vampire Nocturnus

Play with the top card of your library revealed.
As long as the top card of your library is black, Vampire Nocturnus and other Vampire creatures you control get +2/+1 and have flying.

Swamp

Vampire Hexmage

First strike
Sacrifice Vampire Hexmage: Remove all counters from target permanent.

Sorin Markov

+2: Sorin Markov deals 2 damage to any target and you gain 2 life.
−3: Target opponent's life total becomes 10.
−7: You control target player during that player's next turn.