Sengir Vampire

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature dealt damage by Sengir Vampire this turn dies, put a +1/+1 counter on Sengir Vampire.

Blighted Fen

{T}: Add {C}.
{4}{B}, {T}, Sacrifice Blighted Fen: Target opponent sacrifices a creature of their choice.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Walking Corpse

Swamp

Untamed Hunger

Enchant creature
Enchanted creature gets +2/+1 and has menace. (It can't be blocked except by two or more creatures.)

Vampire Envoy

Flying
Whenever Vampire Envoy becomes tapped, you gain 1 life.

Tar Snare

Target creature gets -3/-2 until end of turn.

Dead Weight

Enchant creature
Enchanted creature gets -2/-2.

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Nightmare

Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.

Rottenheart Ghoul

When Rottenheart Ghoul dies, target player discards a card.

Demon's Grasp

Target creature gets -5/-5 until end of turn.

Vampire Noble

Dutiful Return

Return up to two target creature cards from your graveyard to your hand.

Mind Rot

Hagra Sharpshooter

{4}{B}: Target creature gets -1/-1 until end of turn.