Bloodletter of Aclazotz

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

The True Scriptures

(As this Saga enters and after your draw step, add a lore counter.)
I — For each opponent, destroy up to one target creature or planeswalker that player controls.
II — Each opponent discards three cards, then mills three cards.
III — Put all creature cards from all graveyards onto the battlefield under your control. Exile The True Scriptures, then return it to the battlefield (front face up).

Sheoldred

Menace
When Sheoldred enters, each opponent sacrifices a nontoken creature or planeswalker of their choice.
{4}{B}: Exile Sheoldred, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery and only if an opponent has eight or more cards in their graveyard.

Sheoldred // The True Scriptures

Ashnod's Altar

Fell

Sacrifice

As an additional cost to cast this spell, sacrifice a creature.
Add an amount of {B} equal to the sacrificed creature's mana value.

Undying Malice

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Exquisite Blood

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

Peer into the Abyss

Target player draws cards equal to half the number of cards in their library and loses half their life. Round up each time.

Entomb

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

Getting

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Swamp

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents of their choice.

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.

Blood Celebrant

{B}, Pay 1 life: Add one mana of any color.

Font of Agonies

Whenever you pay life, put that many blood counters on Font of Agonies.
{1}{B}, Remove four blood counters from Font of Agonies: Destroy target creature.

Have

Cabal Coffers

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

Ayara, First of Locthwain

Whenever Ayara, First of Locthwain or another black creature you control enters, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

Viscera Seer

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

Feed the Swarm

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

Infernal Grasp

Destroy target creature. You lose 2 life.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Marionette Master

Fabricate 3 (When this creature enters, put three +1/+1 counters on it or create three 1/1 colorless Servo artifact creature tokens.)
Whenever an artifact you control is put into a graveyard from the battlefield, target opponent loses life equal to Marionette Master's power.

Contamination

At the beginning of your upkeep, sacrifice Contamination unless you sacrifice a creature.
If a land is tapped for mana, it produces {B} instead of any other type and amount.

Withering Torment

Destroy target creature or enchantment. You lose 2 life.

Ashnod's Intervention

Until end of turn, target creature gets +2/+0 and gains "When this creature dies or is put into exile from the battlefield, return it to its owner's hand."

Chainer, Dementia Master

All Nightmares get +1/+1.
{B}{B}{B}, Pay 3 life: Put target creature card from a graveyard onto the battlefield under your control. That creature is black and is a Nightmare in addition to its other creature types.
When Chainer, Dementia Master leaves the battlefield, exile all Nightmares.

Sign in Blood

Target player draws two cards and loses 2 life.

Sol Ring

Stinging Study

You draw X cards and you lose X life, where X is the mana value of a commander you own on the battlefield or in the command zone.

Cavalier of Night

Lifelink
When Cavalier of Night enters, you may sacrifice another creature. When you do, destroy target creature an opponent controls.
When Cavalier of Night dies, return target creature card with mana value 3 or less from your graveyard to the battlefield.

Vampire Scrivener

Flying
Whenever you gain life during your turn, put a +1/+1 counter on Vampire Scrivener.
Whenever you lose life during your turn, put a +1/+1 counter on Vampire Scrivener.

Necrotic Ooze

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Magus of the Coffers

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Blood Pet

Beseech the Mirror

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Search your library for a card, exile it face down, then shuffle. If this spell was bargained, you may cast the exiled card without paying its mana cost if that spell's mana value is 4 or less. Put the exiled card into your hand if it wasn't cast this way.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

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.)

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Demonic Tutor

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

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Phyrexian Tower

{T}: Add {C}.
{T}, Sacrifice a creature: Add {B}{B}.

Demonic Consultation

Choose a card name. Exile the top six cards of your library, then reveal cards from the top of your library until you reveal a card with the chosen name. Put that card into your hand and exile all other cards revealed this way.

Torment of Hailfire

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

Arcane Signet

Yawgmoth, Thran Physician

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
{B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

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.

Ad Nauseam

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Demolition Field

{T}: Add {C}.
{2}, {T}, Sacrifice Demolition Field: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

Erebos's Intervention

Choose one —
• Target creature gets -X/-X until end of turn. You gain X life.
• Exile up to twice X target cards from graveyards.

Temporal Extortion

When you cast this spell, any player may pay half their life, rounded up. If a player does, counter Temporal Extortion.
Take an extra turn after this one.

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Saw in Half

Destroy target creature. If that creature dies this way, its controller creates two tokens that are copies of that creature, except their power is half that creature's power and their toughness is half that creature's toughness. Round up each time.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Sanguine Bond

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

Imp's Mischief

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Necromancy

You may cast Necromancy as though it had flash. If you cast it any time a sorcery couldn't have been cast, the controller of the permanent it becomes sacrifices it at the beginning of the next cleanup step.
When Necromancy enters, if it's on the battlefield, it becomes an Aura with "enchant creature put onto the battlefield with Necromancy." Put target creature card from a graveyard onto the battlefield under your control and attach Necromancy to it. When Necromancy leaves the battlefield, that creature's controller sacrifices it.

Castle Locthwain

Castle Locthwain enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Vampiric Tutor

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

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Damnation

Destroy all creatures. They can't be regenerated.

Dark Ritual

Victimize

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

Jet Medallion

Black spells you cast cost {1} less to cast.

Lethal Vapors

Whenever a creature enters, destroy it.
{0}: Destroy Lethal Vapors. You skip your next turn. Any player may activate this ability.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Vilis, Broker of Blood

Flying
{B}, Pay 2 life: Target creature gets -1/-1 until end of turn.
Whenever you lose life, draw that many cards. (Damage causes loss of life.)

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}.

Opposition Agent

Flash
You control your opponents while they're searching their libraries.
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.