Nefarox, Overlord of Grixis

Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever Nefarox, Overlord of Grixis attacks alone, defending player sacrifices a creature.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Slum Reaper

When Slum Reaper enters the battlefield, each player sacrifices a creature.

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, rounded up.

Dreadbore

Flayer of the Hatebound

Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)
Whenever Flayer of the Hatebound or another creature enters the battlefield from your graveyard, that creature deals damage equal to its power to any target.

Desecration Demon

Flying
At the beginning of each combat, any opponent may sacrifice a creature. If a player does, tap Desecration Demon and put a +1/+1 counter on it.

Captive Audience

Captive Audience enters the battlefield under the control of an opponent of your choice.
At the beginning of your upkeep, choose one that hasn't been chosen —
• Your life total becomes 4.
• Discard your hand.
• Each opponent creates five 2/2 black Zombie creature tokens.

Bloodfell Caves

Bloodfell Caves enters the battlefield tapped.
When Bloodfell Caves enters the battlefield, you gain 1 life.
{T}: Add {B} or {R}.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Shimmering Grotto

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Footlight Fiend

When Footlight Fiend dies, it deals 1 damage to any target.

Pilfering Imp

Flying
{1}{B}, {T}, Sacrifice Pilfering Imp: Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. Activate only as a sorcery.

Bedevil

Destroy target artifact, creature, or planeswalker.

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.

Reliquary Tower

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

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Anarchy

Demon of Catastrophes

As an additional cost to cast this spell, sacrifice a creature.
Flying, trample

Demon of Death's Gate

You may pay 6 life and sacrifice three black creatures rather than pay this spell's mana cost.
Flying, trample

Stranglehold

Your opponents can't search libraries.
If an opponent would begin an extra turn, that player skips that turn instead.

Raiders' Wake

Whenever an opponent discards a card, that player loses 2 life.
Raid — At the beginning of your end step, if you attacked this turn, target opponent discards a card.

Sol Ring

Judith, the Scourge Diva

Other creatures you control get +1/+0.
Whenever a nontoken creature you control dies, Judith, the Scourge Diva deals 1 damage to any target.

Rafter Demon

Spectacle {3}{B}{R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
When Rafter Demon enters the battlefield, if its spectacle cost was paid, each opponent discards a card.

Rakdos Guildgate

Rakdos Guildgate enters the battlefield tapped.
{T}: Add {B} or {R}.

Krark's Thumb

If you would flip a coin, instead flip two coins and ignore one.

Dark Ritual

Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Bone Splinters

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

Command Tower

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

Soot Imp

Flying
Whenever a player casts a nonblack spell, that player loses 1 life.

Phyresis

Enchant creature
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

Lavaclaw Reaches

Lavaclaw Reaches enters the battlefield tapped.
{T}: Add {B} or {R}.
{1}{B}{R}: Until end of turn, Lavaclaw Reaches becomes a 2/2 black and red Elemental creature with "{X}: This creature gets +X/+0 until end of turn." It's still a land.

Rakdos Cackler

Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

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.

Profane Memento

Whenever a creature card is put into an opponent's graveyard from anywhere, you gain 1 life.

Angrath's Rampage

Choose one —
• Target player sacrifices an artifact.
• Target player sacrifices a creature.
• Target player sacrifices a planeswalker.

Rakdos Carnarium

Rakdos Carnarium enters the battlefield tapped.
When Rakdos Carnarium enters the battlefield, return a land you control to its owner's hand.
{T}: Add {B}{R}.

Demon of Dark Schemes

Flying
When Demon of Dark Schemes enters the battlefield, all other creatures get -2/-2 until end of turn.
Whenever another creature dies, you get {E} (an energy counter).
{2}{B}, Pay {E}{E}{E}{E}: Put target creature card from a graveyard onto the battlefield under your control tapped.

Demonic Tutor

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

Garna, the Bloodflame

Flash
When Garna, the Bloodflame enters the battlefield, return to your hand all creature cards in your graveyard that were put there from anywhere this turn.
Other creatures you control have haste.

Rakdos, Lord of Riots

You can't cast this spell 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.

Cadaver Imp

Flying
When Cadaver Imp enters the battlefield, you may return target creature card from your graveyard to your hand.

Rakdos Locket

{T}: Add {B} or {R}.
{B/R}{B/R}{B/R}{B/R}, {T}, Sacrifice Rakdos Locket: Draw two cards.

Carrion Imp

Flying
When Carrion Imp enters the battlefield, you may exile target creature card from a graveyard. If you do, you gain 2 life.

Demonic Rising

At the beginning of your end step, if you control exactly one creature, create a 5/5 black Demon creature token with flying.

Theater of Horrors

At the beginning of your upkeep, exile the top card of your library.
During your turn, if an opponent lost life this turn, you may play lands and cast spells from among cards exiled with Theater of Horrors.
{3}{R}: Theater of Horrors deals 1 damage to target opponent or planeswalker.

Doublecast

When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Mindmoil

Whenever you cast a spell, put the cards in your hand on the bottom of your library in any order, then draw that many cards.

Graven Cairns

{T}: Add {C}.
{B/R}, {T}: Add {B}{B}, {B}{R}, or {R}{R}.

Macabre Mockery

Put target creature card from an opponent's graveyard onto the battlefield under your control. It gets +2/+0 and gains haste until end of turn. Sacrifice it at the beginning of the next end step.

Reanimate

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

Daggerdrome Imp

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Ravenous Chupacabra

When Ravenous Chupacabra enters the battlefield, destroy target creature an opponent controls.

Rakdos, the Showstopper

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

Stinkweed Imp

Flying
Whenever Stinkweed Imp deals combat damage to a creature, destroy that creature.
Dredge 5 (If you would draw a card, you may mill five cards instead. If you do, return this card from your graveyard to your hand.)

Panharmonicon

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

Rakdos Keyrune

{T}: Add {B} or {R}.
{B}{R}: Rakdos Keyrune becomes a 3/1 black and red Devil artifact creature with first strike until end of turn.

Angrath, the Flame-Chained

+1: Each opponent discards a card and loses 2 life.
−3: Gain control of target creature until end of turn. Untap it. It gains haste until end of turn. Sacrifice it at the beginning of the next end step if it has mana value 3 or less.
−8: Each opponent loses life equal to the number of cards in their graveyard.

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Wrangle

Gain control of target creature with power 4 or less until end of turn. Untap that creature. It gains haste until end of turn.

Liliana's Contract

When Liliana's Contract enters the battlefield, 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.

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

Sire of Insanity

At the beginning of each end step, each player discards their hand.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

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.

Platinum Emperion

Your life total can't change. (You can't gain or lose life. You can't pay any amount of life except 0.)

Plague Wind

Destroy all creatures you don't control. They can't be regenerated.

Anger

Haste
As long as Anger is in your graveyard and you control a Mountain, creatures you control have haste.

Mirror March

Whenever a nontoken creature enters the battlefield under your control, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

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.