Balemurk Leech

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, each opponent loses 1 life.

Viper's Kiss

Enchant creature
Enchanted creature gets -1/-1, and its activated abilities can't be activated.

Contaminated Ground

Enchant land
Enchanted land is a Swamp.
Whenever enchanted land becomes tapped, its controller loses 2 life.

Grim Guardian

Constellation — Whenever Grim Guardian or another enchantment you control enters, each opponent loses 1 life.

Wicked Visitor

Whenever an enchantment you control is put into a graveyard from the battlefield, each opponent loses 1 life.

Gruesome Deformity

Enchant creature
Enchanted creature has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Stab Wound

Enchant creature
Enchanted creature gets -2/-2.
At the beginning of the upkeep of enchanted creature's controller, that player loses 2 life.

Bloodcrazed Hoplite

Heroic — Whenever you cast a spell that targets Bloodcrazed Hoplite, put a +1/+1 counter on it.
Whenever a +1/+1 counter is put on Bloodcrazed Hoplite, remove a +1/+1 counter from target creature an opponent controls.

Warehouse Tabby

Whenever an enchantment you control is put into a graveyard from the battlefield, create a 1/1 black Rat creature token with "This creature can't block."
{1}{B}: Warehouse Tabby gains deathtouch until end of turn.

Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Sinister Possession

Enchant creature
Whenever enchanted creature attacks or blocks, its controller loses 2 life.

Temple Thief

Temple Thief can't be blocked by enchanted creatures or enchantment creatures.

Clawing Torment

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets -1/-1 and can't block.
Enchanted permanent has "At the beginning of your upkeep, you lose 1 life."

Final Vengeance

As an additional cost to cast this spell, sacrifice a creature or enchantment.
Exile target creature.

Sign in Blood

Target player draws two cards and loses 2 life.

Fear

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

Swamp

Coils of the Medusa

Enchant creature
Enchanted creature gets +1/-1.
Sacrifice Coils of the Medusa: Destroy all non-Wall creatures blocking enchanted creature.

Withercrown

Enchant creature
Enchanted creature has base power 0 and has "At the beginning of your upkeep, you lose 1 life unless you sacrifice this creature."

Thrull Retainer

Enchant creature
Enchanted creature gets +1/+1.
Sacrifice Thrull Retainer: Regenerate enchanted creature.

Skeletal Grimace

Enchant creature
Enchanted creature gets +1/+1 and has "{B}: Regenerate this creature."

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.