Cauldron Familiar

When this creature enters, each opponent loses 1 life and you gain 1 life.
Sacrifice a Food: Return this card from your graveyard to the battlefield.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Epicure of Blood

Whenever you gain life, each opponent loses 1 life.

Marauding Blight-Priest

Alhammarret's Archive

If you would gain life, you gain twice that much life instead.
If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Blood Tribute

Kicker—Tap an untapped Vampire you control. (You may tap a Vampire you control in addition to any other costs as you cast this spell.)
Target opponent loses half their life, rounded up. If this spell was kicked, you gain life equal to the life lost this way.

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Staff of the Death Magus

Whenever you cast a black spell or a Swamp you control enters, you gain 1 life.

Defiant Bloodlord

Flying
Whenever you gain life, target opponent loses that much life.

Leechridden Swamp

({T}: Add {B}.)
This land enters tapped.
{B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.

Swamp

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.