Blood for the Blood God!

This spell costs {1} less to cast for each creature that died this turn.
Discard your hand, then draw eight cards. Blood for the Blood God! deals 8 damage to each opponent. Exile Blood for the Blood God!

Rakdos the Defiler

Flying, trample
Whenever Rakdos 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.

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 token dies, it deals 1 damage to any target."

Bedevil

Destroy target artifact, creature, or planeswalker.

Sower of Discord

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

Ancestral Statue

When this creature enters, return a nonland permanent you control to its owner's hand.

Descent into Avernus

At the beginning of your upkeep, put two descent counters on this enchantment. Then each player creates X Treasure tokens and this enchantment deals X damage to each player, where X is the number of descent counters on this enchantment.

Rakdos's Return

Rakdos's Return deals X damage to target opponent or planeswalker. That player or that planeswalker's controller discards X cards.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Havoc Festival

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

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.)

Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

Doom Blade

Damnation

Destroy all creatures. They can't be regenerated.

Mask of Griselbrand

Equipped creature has flying and lifelink.
Whenever equipped creature dies, you may pay X life, where X is its power. If you do, draw X cards.
Equip {3}

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Fiendish Duo

First strike (This creature deals combat damage before creatures without first strike.)
If a source would deal damage to an opponent, it deals double that damage to that player instead.

Boldwyr Heavyweights

Trample
When this creature enters, each opponent may search their library for a creature card and put it onto the battlefield. Then each player who searched their library this way shuffles.

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.)

Rakdos, Lord of Riots

You can't cast Rakdos 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.

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Plague Drone

Flying
Rot Fly — 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.

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.

Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random. Its controller mills that many cards, then exiles cards from the top of their library until they exile a nonland card with a different name than that spell. They may cast that card without paying its mana cost. Then they put the exiled cards on the bottom of their library in a random order.

Vanquisher's Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

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 this enchantment.
{3}{R}: This enchantment deals 1 damage to target opponent or planeswalker.

Abyssal Persecutor

Flying, trample
You can't win the game and your opponents can't lose the game.

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.

Herald of Slaanesh

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

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Victimize

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

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.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Arcane Signet

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

Heartless Hidetsugu

{T}: Heartless Hidetsugu deals damage to each player equal to half that player's life total, rounded down.

Withering Torment

Destroy target creature or enchantment. You lose 2 life.

Shadowborn Apostle

A deck can have any number of cards named Shadowborn Apostle.
{B}, Sacrifice six creatures named Shadowborn Apostle: Search your library for a Demon creature card, put it onto the battlefield, then shuffle.

Liliana's Contract

When this enchantment 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

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

Rune-Scarred Demon

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

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

Ardyn, the Usurper

Demons you control have menace, lifelink, and haste.
Starscourge — At the beginning of combat on your turn, exile up to one target creature card from a graveyard. If you exiled a card this way, create a token that's a copy of that card, except it's a 5/5 black Demon.

Master of Cruelties

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

Mountain

Swamp

Imp's Mischief

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

Withengar Unbound

Flying, intimidate, trample (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a player loses the game, put thirteen +1/+1 counters on Withengar Unbound.

Elbrus, the Binding Blade

Equipped creature gets +1/+0.
When equipped creature deals combat damage to a player, unattach Elbrus, then transform it.
Equip {1}

Elbrus, the Binding Blade // Withengar Unbound

Bloodthirster

Flying, trample
Whenever this creature deals combat damage to a player, untap it. After this phase, there is an additional combat phase.
This creature can't attack a player it has already attacked this turn.

Dreadbore

Infernal Grasp

Destroy target creature. You lose 2 life.

Boltwave

Boltwave deals 3 damage to each opponent.

Maralen of the Mornsong

Players can't draw cards.
At the beginning of each player's draw step, that player loses 3 life, searches their library for a card, puts it into their hand, then shuffles.