Archfiend of Sorrows

Flying
When Archfiend of Sorrows enters, creatures your opponents control get -2/-2 until end of turn.
Unearth {3}{B}{B} ({3}{B}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Mikaeus, the Unhallowed

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a Human deals damage to you, destroy it.
Other non-Human creatures you control get +1/+1 and have undying. (When a creature with undying 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.)

Hidetsugu, Devouring Chaos

{B}, Sacrifice a creature: Scry 2.
{2}{R}, {T}: Exile the top card of your library. You may play that card this turn. When you exile a nonland card this way, Hidetsugu, Devouring Chaos deals damage equal to the exiled card's mana value to any target.

Orca, Siege Demon

Trample
Whenever another creature dies, put a +1/+1 counter on Orca, Siege Demon.
When Orca dies, it deals damage equal to its power divided as you choose among any number of targets.

Anthem of Rakdos

Whenever a creature you control attacks, it gets +2/+0 until end of turn and Anthem of Rakdos deals 1 damage to you.
Hellbent — As long as you have no cards in hand, if a source you control would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Archfiend of Ifnir

Flying
Whenever you cycle or discard another card, put a -1/-1 counter on each creature your opponents control.
Cycling {2} ({2}, Discard this card: Draw a card.)

Oni of Wild Places

Haste
At the beginning of your upkeep, return a red creature you control to its owner's hand.

Dreadfeast Demon

Flying
At the beginning of your end step, sacrifice a non-Demon creature. If you do, create a token that's a copy of Dreadfeast Demon.

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.

Sol Ring

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.

Dreadhound

When Dreadhound enters, mill three cards. (Put the top three cards of your library into your graveyard.)
Whenever a creature dies or a creature card is put into a graveyard from a library, each opponent loses 1 life.

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.

Impact Tremors

Whenever a creature you control enters, Impact Tremors deals 1 damage to each opponent.

Mandate of Abaddon

Choose target creature you control. Destroy all creatures with power less than that creature's power.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

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.

Dreadbore

Sol'Kanar the Tainted

At the beginning of your end step, choose one that hasn't been chosen —
• Draw a card.
• Each opponent loses 2 life and you gain 2 life.
• Sol'Kanar the Tainted deals 3 damage to up to one other target creature or planeswalker.
• Exile Sol'Kanar, then return it to the battlefield under an opponent's control.

Reaper from the Abyss

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

Dread Cacodemon

When Dread Cacodemon enters, if you cast it from your hand, destroy all creatures your opponents control, then tap all other creatures you control.

Dragonskull Summit

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

Kothophed, Soul Hoarder

Flying
Whenever a permanent owned by another player is put into a graveyard from the battlefield, you draw a card and you lose 1 life.

Terminate

Destroy target creature. It can't be regenerated.

Rakshasa Debaser

Whenever Rakshasa Debaser attacks, put target creature card from defending player's graveyard onto the battlefield under your control.
Encore {6}{B}{B} ({6}{B}{B}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

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.

Arcane Signet

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

Be'lakor, the Dark Master

Flying
Prince of Chaos — When Be'lakor, the Dark Master enters, you draw X cards and you lose X life, where X is the number of Demons you control.
Lord of Torment — Whenever another Demon you control enters, it deals damage equal to its power to any target.

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters tapped unless you control two or more basic lands.

Balor

Flying
Whenever Balor attacks or dies, choose one or more. Each mode must target a different player.
• Target opponent draws three cards, then discards three cards at random.
• Target opponent sacrifices a nontoken artifact of their choice.
• Balor deals damage to target opponent equal to the number of cards in their hand.

Talisman of Indulgence

{T}: Add {C}.
{T}: Add {B} or {R}. Talisman of Indulgence deals 1 damage to you.

Rakdos Signet

Havoc Demon

Flying
When Havoc Demon dies, all creatures get -5/-5 until end of turn.

Swamp

Mark of the Oni

Enchant creature
You control enchanted creature.
At the beginning of the end step, if you control no Demons, sacrifice Mark of the Oni.

Overseer of the Damned

Flying
When Overseer of the Damned enters, you may destroy target creature.
Whenever a nontoken creature an opponent controls dies, create a tapped 2/2 black Zombie creature token.

Lord of Change

Flying, ward {3}
Architect of Deception — When Lord of Change enters, draw three cards.

Soulflayer

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
If a creature card with flying was exiled with Soulflayer's delve ability, Soulflayer has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, reach, trample, and vigilance.

Xathrid Demon

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Xathrid Demon, then each opponent loses life equal to the sacrificed creature's power. If you can't sacrifice a creature, tap Xathrid Demon and you lose 7 life.

Demonlord of Ashmouth

Flying
When Demonlord of Ashmouth enters, exile it unless you sacrifice another creature.
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.)

Gyruda, Doom of Depths

Companion — Your starting deck contains only cards with even mana values. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Gyruda enters, each player mills four cards. Put a creature card with an even mana value from among the milled cards onto the battlefield under your control.

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

Bedevil

Destroy target artifact, creature, or planeswalker.

Reliquary Tower

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

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.)

Izzet Signet

Dimir Signet

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."

Mountain

Herald of Slaanesh

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

Prince of Thralls

Whenever a permanent an opponent controls is put into a graveyard, put that card onto the battlefield under your control unless that opponent pays 3 life.

Hostile Takeover

Up to one target creature has base power and toughness 1/1 until end of turn. Up to one other target creature has base power and toughness 4/4 until end of turn. Then Hostile Takeover deals 3 damage to each creature.

In Garruk's Wake

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

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.

Demonlord Belzenlok

Flying, trample
When Demonlord Belzenlok enters, exile cards from the top of your library until you exile a nonland card, then put that card into your hand. If the card's mana value is 4 or greater, repeat this process. Demonlord Belzenlok deals 1 damage to you for each card put into your hand this way.

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.

Silent-Blade Oni

Ninjutsu {4}{U}{B} ({4}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Silent-Blade Oni deals combat damage to a player, look at that player's hand. You may cast a spell from among those cards without paying its mana cost.

Command Tower

Archfiend of the Dross

Flying
Archfiend of the Dross enters with four oil counters on it.
At the beginning of your upkeep, remove an oil counter from Archfiend of the Dross. Then if it has no oil counters on it, you lose the game.
Whenever a creature an opponent controls dies, its controller loses 2 life.

Burning-Rune Demon

Flying
When Burning-Rune Demon enters, you may search your library for exactly two cards not named Burning-Rune Demon that have different names. If you do, reveal those cards. An opponent chooses one of them. Put the chosen card into your hand and the other into your graveyard, then shuffle.

Sol'kanar the Swamp King

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Whenever a player casts a black spell, you gain 1 life.

Nightmare Shepherd

Flying
Whenever another nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of that creature, except it's 1/1 and it's a Nightmare in addition to its other types.

Demon of Catastrophes

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

Luxury Suite

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

Damnation

Destroy all creatures. They can't be regenerated.

Thought Vessel

Island

Hidetsugu and Kairi

Flying
When Hidetsugu and Kairi enters, draw three cards, then put two cards from your hand on top of your library in any order.
When Hidetsugu and Kairi dies, exile the top card of your library. Target opponent loses life equal to its mana value. If it's an instant or sorcery card, you may cast it without paying its mana cost.

Blade of the Oni

Menace
Equipped creature has base power and toughness 5/5, has menace, and is a black Demon in addition to its other colors and types.
Reconfigure {2}{B}{B} ({2}{B}{B}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Doom Whisperer

Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

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.

Warstorm Surge

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