Nim Deathmantle

Equipped creature gets +2/+2, has intimidate, and is a black Zombie. (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a nontoken creature is put into your graveyard from the battlefield, you may pay {4}. If you do, return that card to the battlefield and attach Nim Deathmantle to it.
Equip {4}

Rite of Belzenlok

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Create two 0/1 black Cleric creature tokens.
III — Create a 6/6 black Demon creature token with flying, trample, and "At the beginning of your upkeep, sacrifice another creature. If you can't, this creature deals 6 damage to you."

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni, Undying Partisan.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Sanguimancy

You draw X cards and you lose X life, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Dark Salvation

Target player creates X 2/2 black Zombie creature tokens, then up to one target creature gets -1/-1 until end of turn for each Zombie that player controls.

Merciless Executioner

When Merciless Executioner enters, each player sacrifices a creature.

Endrek Sahr, Master Breeder

Whenever you cast a creature spell, create X 1/1 black Thrull creature tokens, where X is that spell's mana value.
When you control seven or more Thrulls, sacrifice Endrek Sahr, Master Breeder.

Dark Ritual

Corpse Blockade

Defender
Sacrifice another creature: Corpse Blockade gains deathtouch until end of turn.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Zulaport Cutthroat

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

Burnished Hart

{3}, Sacrifice Burnished Hart: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Ashes to Ashes

Exile two target nonartifact creatures. Ashes to Ashes deals 5 damage to you.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Carrion

As an additional cost to cast this spell, sacrifice a creature.
Create X 0/1 black Insect creature tokens, where X is the sacrificed creature's power.

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.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Massacre Wurm

When Massacre Wurm enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Gravepurge

Put any number of target creature cards from your graveyard on top of your library.
Draw a card.

Consume Spirit

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

Torgaar, Famine Incarnate

As an additional cost to cast this spell, you may sacrifice any number of creatures. This spell costs {2} less to cast for each creature sacrificed this way.
When Torgaar, Famine Incarnate enters, up to one target player's life total becomes half their starting life total, rounded down.

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature.

Ruthless Knave

{2}{B}, Sacrifice a creature: Create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")
Sacrifice three Treasures: Draw a card.

Extinguish All Hope

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature.

Sengir Autocrat

When Sengir Autocrat enters, create three 0/1 black Serf creature tokens.
When Sengir Autocrat leaves the battlefield, exile all Serf tokens.

Rhystic Tutor

Unless any player pays {2}, search your library for a card, put that card into your hand, then shuffle.

Dark Prophecy

Whenever a creature you control dies, you draw a card and you lose 1 life.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Magus of the Coffers

{2}, {T}: Add {B} for each Swamp you control.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Sanguine Bond

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

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Ambition's Cost

You draw three cards and you lose 3 life.

Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Ogre Slumlord

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.
Rats you control have deathtouch.

Tectonic Edge

{T}: Add {C}.
{1}, {T}, Sacrifice Tectonic Edge: Destroy target nonbasic land. Activate only if an opponent controls four or more lands.

Pontiff of Blight

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Other creatures you control have extort. (If a creature has multiple instances of extort, each triggers separately.)

Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Pawn of Ulamog

Whenever Pawn of Ulamog or another nontoken creature you control dies, you may create a 0/1 colorless Eldrazi Spawn creature token. It has "Sacrifice this creature: Add {C}."

Ormendahl, Profane Prince

Westvale Abbey

{T}: Add {C}.
{5}, {T}, Pay 1 life: Create a 1/1 white and black Human Cleric creature token.
{5}, {T}, Sacrifice five creatures: Transform Westvale Abbey, then untap it.

Westvale Abbey // Ormendahl, Profane Prince

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Barren Moor

Barren Moor enters tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

Weaponcraft Enthusiast

Fabricate 2 (When this creature enters, put two +1/+1 counters on it or create two 1/1 colorless Servo artifact creature tokens.)

Bone Splinters

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

Sign in Blood

Target player draws two cards and loses 2 life.

Disciple of Griselbrand

{1}, Sacrifice a creature: You gain life equal to the sacrificed creature's toughness.

Gravedigger

When Gravedigger enters, you may return target creature card from your graveyard to your hand.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Songs of the Damned

Add {B} for each creature card in your graveyard.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Hedron Archive: Draw two cards.

Swamp

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Read the Bones

Scry 2, then draw two cards. You lose 2 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.)

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Whip of Erebos

Creatures you control have lifelink.
{2}{B}{B}, {T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step. If it would leave the battlefield, exile it instead of putting it anywhere else. Activate only as a sorcery.

Exquisite Blood

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

Reassembling Skeleton

{1}{B}: Return Reassembling Skeleton from your graveyard to the battlefield tapped.

Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Disciple of Bolas

When Disciple of Bolas enters, sacrifice another creature. You gain X life and draw X cards, where X is that creature's power.

Breeding Pit

At the beginning of your upkeep, sacrifice Breeding Pit unless you pay {B}{B}.
At the beginning of your end step, create a 0/1 black Thrull creature token.