Vampire Hexmage

First strike
Sacrifice this creature: Remove all counters from target permanent.

Dark Ritual

Whenever you gain life, each opponent loses 1 life.

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

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

Spend only black mana on X.
Consume Spirit deals X damage to any target and you gain X life.

Flying
If an opponent would lose life during your turn, they lose twice that much life instead. (Damage causes loss of life.)

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.