Ob Nixilis of the Black Oath

+2: Each opponent loses 1 life. You gain life equal to the life lost this way.
−2: Create a 5/5 black Demon creature token with flying. You lose 2 life.
−8: You get an emblem with "{1}{B}, Sacrifice a creature: You gain X life and draw X cards, where X is the sacrificed creature's power."
Ob Nixilis of the Black Oath can be your commander.

Demonic Counsel

Search your library for a Demon card, reveal it, put it into your hand, then shuffle.
Delirium — If there are four or more card types among cards in your graveyard, instead search your library for any card, put it into your hand, then shuffle.

Rune-Scarred Demon

Flying
When this creature enters, search your library for a card, put it into your hand, then shuffle.

Rakdos, the Showstopper

Flying, trample
When Rakdos, the Showstopper enters, flip a coin for each creature that isn't a Demon, Devil, or Imp. Destroy each creature whose coin comes up tails.

Vedalken Orrery

You may cast spells as though they had flash.

Haunted Ridge

Haunted Ridge enters tapped unless you control two or more other lands.
{T}: Add {B} or {R}.

Rakdos the Defiler

Flying, trample
Whenever Rakdos the Defiler attacks, sacrifice half the non-Demon permanents you control, rounded up.
Whenever Rakdos deals combat damage to a player, that player sacrifices half the non-Demon permanents they control of their choice, rounded up.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or 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.

Tainted Peak

{T}: Add {C}.
{T}: Add {B} or {R}. Activate only if you control a Swamp.

Demonic Tutor

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

Exquisite Blood

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

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.

Reiver Demon

Flying
When Reiver Demon enters, if you cast it from your hand, destroy all nonartifact, nonblack creatures. They can't be regenerated.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Liliana's Contract

When Liliana's Contract enters, you draw four cards and you lose 4 life.
At the beginning of your upkeep, if you control four or more Demons with different names, you win the game.

Sol Ring

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.)

Diabolic Tutor

Mithril Coat

Flash
Indestructible
When Mithril Coat enters, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

Ob Nixilis, Captive Kingpin

Flying, trample
Whenever one or more opponents each lose exactly 1 life, put a +1/+1 counter on Ob Nixilis, Captive Kingpin. Exile the top card of your library. Until your next end step, you may play that card.

Séance Board

Morbid — At the beginning of each end step, if a creature died this turn, put a soul counter on Séance Board.
{T}: Add X mana of any one color, where X is the number of soul counters on Séance Board. Spend this mana only to cast instant, sorcery, Demon, and Spirit spells.

Reanimate

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

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Rakdos, Patron of Chaos

Flying, trample
At the beginning of your end step, target opponent may sacrifice two nonland, nontoken permanents of their choice. If they don't, you draw two cards.

Raphael, Fiendish Savior

Flying
Other Demons, Devils, Imps, and Tieflings you control get +1/+1 and have lifelink.
At the beginning of each end step, if a creature card was put into your graveyard from anywhere this turn, create a 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target."

Jet Medallion

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

Harvester of Souls

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another nontoken creature dies, you may draw a card.

Indulgent Tormentor

Flying
At the beginning of your upkeep, draw a card unless target opponent sacrifices a creature of their choice or pays 3 life.

Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

Bolt Bend

This spell costs {3} less to cast if you control a creature with power 4 or greater.
Change the target of target spell or ability with a single target.

Luxury Suite

Luxury Suite enters tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Aurora of Emrakul

Flying, deathtouch
Whenever Aurora of Emrakul attacks, each opponent loses 3 life.

Cryptolith Fragment

Cryptolith Fragment enters tapped.
{T}: Add one mana of any color. Each player loses 1 life.
At the beginning of your upkeep, if each player has 10 or less life, transform Cryptolith Fragment.

Cryptolith Fragment // Aurora of Emrakul

Blazemire Verge

{T}: Add {B}.
{T}: Add {R}. Activate only if you control a Swamp or a Mountain.

Sower of Discord

Flying
As Sower of Discord enters, choose two players.
Whenever damage is dealt to one of the chosen players, the other chosen player also loses that much life.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Valakut Stoneforge

Valakut Stoneforge enters tapped.
{T}: Add {R}.

Valakut Awakening

Put any number of cards from your hand on the bottom of your library, then draw that many cards plus one.

Valakut Awakening // Valakut Stoneforge

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Lord of the Void

Flying
Whenever Lord of the Void deals combat damage to a player, exile the top seven cards of that player's library, then put a creature card from among them onto the battlefield under your control.

Shadowgrange Archfiend

When Shadowgrange Archfiend enters, each opponent sacrifices a creature with the greatest power among creatures they control. You gain life equal to the greatest power among creatures sacrificed this way.
Madness—{2}{B}, Pay 8 life. (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Reaper from the Abyss

Flying
Morbid — At the beginning of each end step, if a creature died this turn, destroy target non-Demon creature.

Urza's Incubator

As Urza's Incubator enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Sanguine Syphoner

Whenever this creature attacks, each opponent loses 1 life and you gain 1 life.

Sanctum of Stone Fangs

At the beginning of your first main phase, each opponent loses X life and you gain X life, where X is the number of Shrines you control.

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.)

Cryptothrall

Protector — Other artifact creatures you control have hexproof.

Valgavoth, Terror Eater

Flying, lifelink
Ward—Sacrifice three nonland permanents.
If a card you didn't control would be put into an opponent's graveyard from anywhere, exile it instead.
During your turn, you may play cards exiled with Valgavoth. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.

Rakdos, Lord of Riots

You can't cast Rakdos, Lord of Riots unless an opponent lost life this turn.
Flying, trample
Creature spells you cast cost {1} less to cast for each 1 life your opponents have lost this turn.

Bedevil

Destroy target artifact, creature, or planeswalker.

Orcus, Prince of Undeath

Flying, trample
When Orcus, Prince of Undeath enters, choose one —
• Each other creature gets -X/-X until end of turn. You lose X life.
• Return up to X target creature cards with total mana value X or less from your graveyard to the battlefield. They gain haste until end of turn.

Ob Nixilis, the Fallen

Landfall — Whenever a land you control enters, you may have target player lose 3 life. If you do, put three +1/+1 counters on Ob Nixilis, the Fallen.

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Master of Cruelties

First strike, deathtouch
Master of Cruelties can only attack alone.
Whenever Master of Cruelties attacks a player and isn't blocked, that player's life total becomes 1. Master of Cruelties assigns no combat damage this combat.

Vampiric Tutor

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

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

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.)

Spawn of Mayhem

Spectacle {1}{B}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Flying, trample
At the beginning of your upkeep, Spawn of Mayhem deals 1 damage to each player. Then if you have 10 or less life, put a +1/+1 counter on Spawn of Mayhem.

Herald of Slaanesh

Locus of Slaanesh — Demon spells you cast cost {2} less to cast.
Other Demons you control have haste.

Archfiend of Despair

Flying
Your opponents can't gain life.
At the beginning of each end step, each opponent loses life equal to the life that player lost this turn. (Damage causes loss of life.)

Razaketh, the Foulblooded

Flying, trample
Pay 2 life, Sacrifice another creature: Search your library for a card, put that card into your hand, then shuffle.

Bringer of the Last Gift

Flying
When Bringer of the Last Gift enters, if you cast it, each player sacrifices all other creatures they control. Then each player returns all creature cards from their graveyard that weren't put there this way to the battlefield.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Bloodgift Demon

Flying
At the beginning of your upkeep, target player draws a card and loses 1 life.

Archfiend of Depravity

Flying
At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.

Pestilence Demon

Flying
{B}: Pestilence Demon deals 1 damage to each creature and each player.

Boltwave

Boltwave deals 3 damage to each opponent.

Deadly Rollick

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

Ob Nixilis, Unshackled

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis, Unshackled.

Plague Drone

Flying
Rot Fly — If an opponent would gain life, that player loses that much life instead.

Court of Ambition

When Court of Ambition enters, you become the monarch.
At the beginning of your upkeep, each opponent loses 3 life unless they discard a card. If you're the monarch, instead each opponent loses 6 life unless they discard two cards.

Mountain

Exsanguinate

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

Kardur, Doomscourge

When Kardur, Doomscourge enters, until your next turn, creatures your opponents control attack each combat if able and attack a player other than you if able.
Whenever an attacking creature dies, each opponent loses 1 life and you gain 1 life.